Seat and cushion pad

Abstract

Provided are a seat in which a cushion pad is reduced in thickness while improving a bottomed feel, and a cushion pad that is reduced in thickness while improving a bottomed feel. This seat comprises a cushion pad for supporting a seated user. The cushion pad includes a first sheet material that is formed of a resin, and a second sheet material that is formed of a resin and is laminated on the lower-surface side of the first sheet material. The second sheet material is thinner than the first sheet material and is softer than the first sheet material.

Description

Seats and cushion pads

[0001] The present disclosure relates to seats and cushion pads.

[0002] Patent Document 1 discloses a flexible polyurethane foam for automobile seat cushions and a method for producing the same. This flexible polyurethane foam for automobile seat cushions is produced by mixing a diphenylmethane diisocyanate-based polyisocyanate and a polyol component in the presence of a catalyst, a foam stabilizer, and a blowing agent, and then injecting the mixture into a mold to form the foam. In this flexible polyurethane foam for automobile seat cushions, the difference between the core density and the total density of the foam is 5 kg / m. ３ Patent Document 1 describes that this flexible polyurethane foam for automobile seat cushions is excellent in productivity and working environment, and also eliminates the feeling of hitting the bottom when the automobile seat cushion pad is made thin, thereby providing excellent riding comfort.

[0003] Patent Document 2 discloses a layered differential hardness pad for a vehicle seat. This layered differential hardness pad is composed of two foam layers, upper and lower, with the upper layer being made of polyurethane foam and the lower layer being made of polystyrene foam. The upper and lower layers are bonded together. It is said that the lower layer preferably accounts for 20% to 50% of the product thickness of the layered differential hardness pad. This layered differential hardness pad is said to have better cushioning performance than conventional products.

[0004] JP 2010-280855 JP 09-070330

[0005] In vehicles such as automobiles, it is necessary to ensure sufficient interior space for the user to sit in. Furthermore, in vehicles equipped with storage batteries, such as electric vehicles (EVs) and hybrid cars (HVs), it is necessary to ensure space to accommodate the storage batteries. If the cushion pads (seat pads) in vehicle seats can be made thinner, it will be possible to ensure sufficient interior space for the user to sit in. Furthermore, if the cushion pads can be made thinner, it will also be possible to ensure space for installing storage batteries under the seats. Therefore, there is a demand for increasingly thinner cushion pads.

[0006] However, when the cushion pad is made thinner, it is more likely that the user sitting on it will feel like they are hitting the bottom. Therefore, the conventional technologies such as those exemplified in Patent Documents 1 and 2 above have not been able to sufficiently achieve both further thinning and an improvement in the feeling of hitting the bottom (eliminating the feeling of hitting the bottom). Therefore, it is desired to provide a seat with a thinner cushion pad while improving the feeling of hitting the bottom, and a cushion pad with a thinner thickness while improving the feeling of hitting the bottom.

[0007] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a seat having a thin cushion pad while improving the feeling of hitting the bottom, and a thin cushion pad while improving the feeling of hitting the bottom.

[0008] In order to achieve the above object, the seat of the present disclosure includes a cushion pad that supports a seated user, the cushion pad having a first sheet material formed of resin and a second sheet material also formed of resin that is laminated on the underside of the first sheet material, the second sheet material being thinner than the first sheet material and having a lower hardness than the first sheet material.

[0009] In order to achieve the above object, the seat according to the present disclosure includes a cushion pad that supports a seated user, the cushion pad having a sheet material formed of resin, the sheet material being a rectangular plate material with sides of 50 mm and a thickness of 40 mm as a test piece, and the loss spring constant determined by a dynamic spring test in which the test piece is vibrated at a frequency of 0.5 Hz to 10 Hz with an amplitude of 2.5 mm above and below in the thickness direction from a state in which the thickness of the test piece is compressed by 30%, is 0.2 N / mm to 0.5 N / mm.

[0010] In order to achieve the above object, the cushion pad according to the present disclosure includes a first sheet material formed of resin, and a second sheet material formed of resin and laminated on the lower surface side of the first sheet material, wherein the second sheet material is thinner than the first sheet material and has a lower hardness than the first sheet material.

[0011] According to the present disclosure, it is possible to provide a seat in which the cushion pad is made thinner while improving the feeling of bottoming out, and a cushion pad in which the cushion pad is made thinner while improving the feeling of bottoming out.

[0012] 3 is a perspective view of a seat according to the present embodiment; FIG. 4 is a perspective view of a cushion pad according to the present embodiment; FIG. 5 is a cross-sectional view taken along the line III-III in FIG. 2; FIG. 6 is an explanatory diagram of a vehicle equipped with a seat according to the present embodiment; FIG. 7 is an explanatory diagram of a test piece in an example; FIG. 8 is an explanatory diagram of obtaining an FS curve using a test piece; FIG. 9 is an FS curve of a test piece in each experimental example; FIG. 10 is a measurement result of the loss spring constant of each substrate; FIG. 11 is a drop weight test result of each substrate; FIG. 12 is an explanatory diagram of another seat pad;

[0013] (Description of Embodiments) A seat and a cushion pad according to an embodiment of the present disclosure will be described with reference to the drawings.

[0014] As shown in Fig. 1, a seat 200 according to this embodiment includes a cushion pad 100 that supports a seated user. Fig. 1 is a perspective view of the seat 200 as seen obliquely from the front.

[0015] In FIG. 1 , the width direction (left-right direction) as seen by a user seated in seat 200 is indicated as direction X, the front-rear direction is indicated as direction Y, and the up-down direction is indicated as direction Z. Note that the up-down direction is the same as the vertical direction in this embodiment. The up-down direction, width direction, and front-rear direction are all orthogonal to each other. In the following explanation, the positional relationship of each part will be explained based on the directions shown in FIG. 1 .

[0016] 2 and 3, the cushion pad 100 includes a first sheet material 21 made of resin and a second sheet material 22 made of resin and laminated on the lower surface side of the first sheet material 21, the second sheet material 22 being thinner and lower in hardness than the first sheet material 21. Note that FIG. 2 is a perspective view of the cushion pad 100 as seen from an oblique front. Also, FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2.

[0017] The cushion pad 100 can achieve both an improvement in the bottoming out feeling in the seat 200 and a reduction in thickness. The bottoming out feeling refers to a feeling that occurs when the cushion pad 100 is unable to sufficiently support the weight of the user when the user sits on the seat 200 (see FIG. 1 ), and the user is unable to feel the cushioning properties of the cushion pad 100 and feels hardness. The feeling of bottoming out is usually an uncomfortable state.

[0018] The seat 200 and the cushion pad 100 will be described in detail below.

[0019] The seat 200 shown in Fig. 1 is installed in the interior of a vehicle such as an automobile, and is seated by a user. The seat 200 may, for example, include a seat portion 91 on which the user places their buttocks, a backrest portion 92 against which the user leans, and a headrest 93 (headrest) against which the user leans their head. In this embodiment, in the front-to-rear direction, the side of the seat portion 91 as viewed from the backrest portion 92 is the front (front, forward direction), and the side of the backrest portion 92 as viewed from the seat portion 91 is the rear (rear, rear direction). The front-to-rear direction in the following description will be described based on this positional relationship.

[0020] The seat 200 may have, inside its cover, a cushioning member (seat pad) that conforms to the shape of the seat 200. The seat 200 in this embodiment has a cushion pad 100 inside the seat portion 91 (inside the cover of the seat 200) as this seat pad. The cushion pad 100 is a cushioning member inside the seat portion 91 that supports a user seated on the seat portion 91.

[0021] As shown in FIGS. 2 and 3, the cushion pad 100 includes a first pad 10 and a second sheet material 22 serving as a second pad.

[0022] The first pad 10 may have a seat pad 11 having a first sheet material 21, side pad portions 12, 12 arranged on both sides of the seat pad 11 (both ends in the width direction), and a back pad portion 13 arranged at the rear end of the seat pad 11 in the front-to-back direction.

[0023] The seat pad 11 is placed on the seat 200 below the area where the user's buttocks would be located. The seat pad 11 may be a plate-like member having a thickness in the vertical direction. The thickness of the seat pad 11 is, for example, 50 mm to 120 mm. The upper surfaces of the side pad portions 12 and the back pad portion 13 may be located at a higher position than the upper surface of the seat pad 11.

[0024] The first pad 10, i.e., the seat pad 11, the side pad portions 12, 12, and the back pad portion 13, may be integrally molded from the same base material, for example. An example of the base material forming the first pad 10 is a resin foam. The resin foam is preferably polyurethane, but may be formed from other resins. The first pad 10 may be formed by, for example, injection foam molding.

[0025] The first sheet material 21 is a part of the central portion of the plate-shaped seat pad 11 or the entire seat pad 11. The thickness of the first sheet material 21 is, for example, 30 mm or more and 60 mm or less.

[0026] The hardness of the first sheet material 21 is preferably 170 N or more and 240 N or less. In this embodiment, "hardness" refers to a value measured in accordance with the JASO B408-89 method, which involves compressing a sample by a constant 25% of its original thickness and determining the force after 20 seconds. It is more preferable that the hardness of the first sheet material 21 be 170 N or more and 240 N or less when the thickness is 50 mm.

[0027] The second sheet material 22 is a plate-like member laminated with the first sheet material 21 in the cushion pad 100. Examples of the base material forming the second sheet material 22 are a resin foam and a gel-like sheet material. When the base material forming the second sheet material 22 is a resin foam, the resin foam is preferably polyurethane, but may be formed from other resins.

[0028] The second sheet material 22 overlaps with the first sheet material 21 in the vertical direction. It is preferable that the entire plate surface of the second sheet material 22 overlaps with the first sheet material 21 in the vertical direction. The second sheet material 22 is disposed below the first sheet material 21. Figure 3 and other figures illustrate an example in which the second sheet material 22 is disposed in contact with the lower surface of the first sheet material 21.

[0029] The second sheet material 22 may be fixed to the first sheet material 21 by adhesive or the like, or may simply be overlapped. Alternatively, the second sheet material 22 may be formed into a plate shape, and then the plate may be placed in a mold for injection foam molding the first sheet material 21 (cushion pad 100), and the second sheet material 22 may be fixed to the first sheet material 21 while the first sheet material 21 is being formed (so-called mold forming).

[0030] The second sheet material 22 is thinner than the first sheet material 21. The thickness of the second sheet material 22 may be 0.10 to 0.40 times the thickness of the first sheet material, preferably 0.10 to 0.35 times, and more preferably 0.15 to 0.25 times. The thickness of the second sheet material is preferably 5 mm to 15 mm.

[0031] The second sheet material 22 has a lower hardness than the first sheet material 21. By adjusting the balance between the hardness of the second sheet material 22 and the hardness of the first sheet material 21 in this manner, it is possible to improve the feeling of bottoming out in the seat 200 (see FIG. 1 ) and reduce the total thickness of the cushion pad 100 (see FIG. 2 ), particularly the seat pad 11, and the second sheet material 22. The hardness of the second sheet material 22 is, for example, 150 N or more and 230 N or less. That is, the second sheet material 22 is preferably a rectangular (square) test piece (test piece for hardness measurement) cut into a plate with a thickness of 50 mm and a side length of 300 mm. A circular plate with a diameter of 200 mm is used as a loader to compress the test piece by 25%. The hardness is preferably 150 N or more and 230 N or less.

[0032] In the following description, the improvement in the feeling of hitting the bottom of the seat 200 will be simply referred to as the improvement in the feeling of hitting the bottom. Also, the reduction in the total thickness of the seat pad 11 and the second sheet material 22 will be simply referred to as the reduction in thickness.

[0033] The hardness of the second sheet material 22 is preferably 0.75 to 0.98 times the hardness of the first sheet material 21. If the second sheet material 22 has such hardness, it is possible to better achieve both an improvement in the bottoming out feeling and a thinner material. Note that if the difference in hardness between the second sheet material 22 and the first sheet material 21 is too large, that is, if the hardness of the second sheet material 22 is too small compared to the hardness of the first sheet material 21, the second sheet material 22 may be crushed too much (completely compressed) when the user sits on the cushion pad 100 (seat 200), resulting in a bottoming out feeling.

[0034] The hardness of the second sheet material 22 is preferably at least 5 N less than the hardness of the first sheet material 21. By making the second sheet material 22 have such a hardness, it is possible to better achieve both an improvement in the bottoming out feeling and a thinner wall.

[0035] The total thickness of the second sheet material 22 and the first sheet material 21 need only be 70 mm or less. This total thickness is preferably 60 mm or less. As a result, with the cushion pad 100, due to the effect of improving the bottoming out feeling, even if the thickness of the cushion pad 100, i.e., the total thickness of the seat pad 11 and the second sheet material 22, is reduced, the user will not feel the bottoming out feeling.

[0036] The second sheet material 22 preferably has a suitably small loss spring constant. Specifically, the second sheet material 22 is a test piece (dynamic spring test piece) made of a rectangular (square) plate material with sides of 50 mm and a thickness of 40 mm, and the test piece is vibrated with an amplitude of 2.5 mm up and down in the thickness direction of the test piece, with the center (center of amplitude) being a state where the thickness of the test piece is compressed by 30% (in this example, compressed by 12 mm), at a frequency (frequency) of 0.5 Hz to 10 Hz. The loss spring constant determined by this dynamic spring test is preferably 0.2 N / mm to 0.5 N / mm. This may further improve the bottoming out feeling.

[0037] The air permeability in the thickness direction of the second sheet material 22 is 50 cm when measured in accordance with the air permeability test specified in JIS L 1096. ３ / cm ２ / s or more 300cm ３ / cm ２ It is sufficient, and preferably 100 cm ３ / cm ２ / s or more 300cm ３ / cm ２ , more preferably 125 cm ３ / cm ２ / s or more 180cm ３ / cm ２ , most preferably 125 cm ３ / cm ２ / s or more 150cm ３ / cm ２ This may weaken the damping property in the thickness direction of the cushion pad 100 (second sheet material 22), thereby improving the comfort of sitting.

[0038] Fig. 4 shows a vehicle C equipped with a seat 200 including a cushion pad 100. Fig. 4 illustrates an example in which the traveling direction of the vehicle C is the forward direction in the fore-and-aft direction with the seat 200 as the reference. In the vehicle C, the cushion pad 100 is thinned, and thus the thickness of the seat 200 in the up-down direction can be reduced, thereby ensuring a sufficient size of the interior space S (the height of the interior space S) even when, for example, the vehicle height is lowered. Furthermore, in the vehicle C, the cushion pad 100 is thinned, and therefore a large storage space Sb can be ensured for the storage container M that stores the storage battery B and is disposed below the seat 200.

[0039] (Example) The following describes the improvement of the bottoming feeling and the thinning of the seat and cushion pad based on an example.

[0040] In this example, a test piece (a test piece for obtaining an F-S curve) was used, which was a laminate of a first plate material corresponding to the first sheet material described in the above embodiment and a second plate material corresponding to the second sheet material, and an evaluation was performed on the improvement of the bottoming out feeling. The evaluation of the bottoming out feeling was performed based on the relationship between the load and the amount of deformation (F-S curve), which was obtained by applying a load to the entire plate surface of the test piece and measuring the amount of deformation (deflection) corresponding to the load. The F-S curve was obtained by increasing and then decreasing the load back and forth.

[0041] 5 and 6 show explanatory diagrams of a test specimen and the acquisition of an F-S curve using the same. The laminated plate material 5 used as the test specimen is formed by laminating a first plate material, slab 51, and a second plate material, slab 52. Although the shape is not shown in FIGS. 5 and 6, the external shape of the laminated plate material 5 is the shape of an actual rear cushion, and the target portion for acquiring the F-S curve (target portion for measurement) is in the laminated state shown in FIGS. 5 and 6. In FIG. 5, the thickness of the laminated plate material 5 is shown as plate thickness t, the thickness of the slab 51 as plate thickness t1, and the thickness of the slab 52 as plate thickness t2.

[0042] When obtaining the F-S curve, as shown in Fig. 6, a load F is applied evenly to the entire surface of the laminated plate material 5 to compress the laminated plate material 5, and the amount of reduction in thickness x is obtained and used as the amount of deflection. The amount of reduction x is the thickness of the laminated plate material 5 when the load F is not applied to the laminated plate material 5 (plate thickness t) minus the thickness of the laminated plate material 5 when the load F is applied to the laminated plate material 5 (plate thickness ta).

[0043] In this example, test specimens were manufactured by varying the combination of the first plate material and the second plate material as shown in each experimental example described below, and FS curves were obtained for these test specimens. The FS curves were obtained based on the JASO B408-89 method. The test specimens were 60 mm thick, actual rear cushions (plate-shaped portions to be measured having a thickness of 60 mm), as described below. The load element used for the measurement was an iron grinding plate defined in JASO B 407 (Method for testing cushioning properties of automobile seats). The size of the load element (iron grinding plate) was a rectangle measuring 300 mm x 250 mm. Using the substrate of the first plate material, a test specimen (simulated cushion pad, test specimen for drop weight test) of an actual rear cushion (plate-shaped portions to be measured having a thickness of 60 mm) having a thickness of 60 mm was molded, and this simulated cushion pad was used as the test specimen for Experimental Example 1. Furthermore, a rectangular parallelepiped recess measuring 280 mm in width, 220 mm in the front-to-back direction, and 10 mm in thickness was formed on the back side of this simulated cushion pad directly below the buttocks, and a second plate material with a plate-like shape and a thickness that matched this recess was fitted into it to create test specimens for Experimental Examples 2 to 5.

[0044] Table 1 shows the thickness of the first plate (plate thickness t1, unit: mm) and the thickness of the second plate (plate thickness t2, unit: mm) of the measurement target portion in the experimental examples (Experimental Examples 1 to 5) verified in this example, the type and hardness (N) of the base material of the second plate, and the air permeability (unit: cm ３ / cm ２ / s). In Table 1, the base materials A, B, C, and D of the second plate material are polyurethane resin foams of different specifications. Each base material has a different resin skeleton, degree of polymerization, molecular weight, density, etc. The first plate material forming the first sheet material is a polyurethane resin foam, and its hardness is 205 N when the plate thickness is 60 mm and 224 N when the plate thickness is 50 mm. The hardness of the second plate material forming the second sheet material is the hardness when it is rectangular with a side length of 300 mm and a plate thickness of 50 mm. Figure 7 also shows the F-S curves of the test pieces in these experimental examples. In Figure 7, the horizontal axis represents deflection (mm) and the vertical axis represents load (N).

[0045]

[0046] In the FS curve shown in FIG. 7, the slope of the graph corresponds to the spring constant of the test piece for each experimental example.

[0047] The state in which a user sitting in a seat feels a stronger bottoming out can be rephrased as a state in which the spring constant of the seat pad becomes larger (for example, larger than a predetermined spring constant) when the user sits in the seat, i.e., when a load corresponding to the user's weight is applied to the seat. In other words, a state in which the seat pad's spring constant becomes larger means that the user's body (buttocks, etc.) is less likely to sink in as the user applies more weight to the seat. In this state, the user feels that the seat is hard (lacks cushioning) (i.e., feels a bottoming out).

[0048] Now, when a user is seated in a seat, the typical range of the load applied to the seat pad is 400 N or more and 600 N or less. Therefore, if the spring constant of the seat pad is not too large when the load applied to the cushion pad is in the range of 400 N or more and 600 N or less, the user is less likely to feel the seat pad bottoming out. Furthermore, if the fluctuation in the spring constant is small in the range of 400 N or more and 600 N or less, the user will not feel the seat pad becoming harder as the user adds more weight to the seat, and the user will be even less likely to feel the seat pad bottoming out. Therefore, hereinafter, the smaller the spring constant is in the range of 400 N or more and the smaller the fluctuation in the spring constant within this range, the better the cushion pad will be. Note that a state in which the spring constant of the cushion pad is large in the F-S curve is synonymous with a state in which the slope of the curve is steep. In other words, the spring constant of the cushion pad is the derivative value of the F-S curve.

[0049] Experimental Example 1 has a configuration corresponding to the prior art, in which the cushion pad is one layer. Therefore, hereinafter, the magnitude of the spring constant and the magnitude of the fluctuation in the spring constant will be judged based on the results of Experimental Example 1. In other words, the smaller the spring constant is than the results of Experimental Example 1 in the range of 400 N or more and 600 N or less, and the smaller the fluctuation in the spring constant is in this range than the results of Experimental Example 1, the better the product will be judged to be.

[0050] Judging based on Experimental Example 1, Experimental Examples 2 and 5 are good experimental examples in that they have a smaller spring constant than Experimental Example 1 in the range of 400 N or more and 600 N or less, and the fluctuation in the spring constant in this range is smaller than Experimental Example 1. In other words, Experimental Examples 2 and 5 achieve a thinner wall while improving the bottoming out feeling.

[0051] Experimental Examples 3 and 4 are not good because the spring constants are larger than those of Experimental Example 1 in the range of 400N or more and 600N or less, and the fluctuation in the spring constant in this range is larger than that of Experimental Example 1.

[0052] Therefore, in Table 2, Experimental Examples 1, 3, and 4 are referred to as Comparative Examples 1, 2, and 3, and Experimental Examples 2 and 5 are referred to as Examples 1 and 2.

[0053] A closer look at Experimental Examples 2 and 5 (Examples 1 and 2) reveals the following: When the hardness of the second plate is greater than the hardness of the first plate, as in Experimental Examples 3 and 4 (Comparative Examples 2 and 3), it is thought that a bottoming-out sensation is felt. In contrast, when the hardness of the second plate is moderately smaller than the hardness of the first plate, as in Experimental Examples 2 and 5, it is thought that a bottoming-out sensation is less felt.

[0054] Based on the results of Experimental Examples 2 and 5, it appears that the hardness of the second plate material should preferably be 0.75 to 0.98 times that of the first plate material. It also appears that the hardness of the second plate material should preferably be 150 N or more, which is 5 N or more less than the hardness of the first plate material.

[0055] When the plate material is a resin foam, there is not necessarily a fixed relationship between the hardness and the air permeability of the plate material. However, within the range confirmed in this example, the air permeability is 125 cm ３ / cm ２ / s or more 150cm ３ / cm ２ It seems that it is best to keep it below / s.

[0056] Furthermore, when the loss spring constant of the base material of the plate material used in each experimental example was confirmed, it seemed that the loss spring constant should be at least 0.2 N / mm or more and 0.5 N / mm or less. Figure 8 shows the measurement results of the loss spring constant of the plate material used in each experimental example. In Figure 8, the base materials A to D of the second plate material used in Experimental Examples 2 to 5 are shown as base materials A to D. The base material of the first plate material used in Experimental Examples 1 to 5 is shown as REF. The loss spring constants shown in Figure 8 were determined by a dynamic spring test in which each base material was used as a rectangular (square) test piece with a thickness of 40 mm, and the test piece was vibrated at a frequency (frequency) of 0.5 Hz to 10 Hz with an amplitude of 2.5 mm above and below in the thickness direction of the test piece, centered on a state where the thickness of the test piece was compressed by 30%. 8, the loss spring constants of the substrates A and D used in Experimental Examples 2 and 5 (Examples 1 and 2) are smaller than that of the substrate used as REF, being at least 0.2 N / mm or more and 0.5 N / mm or less. It is estimated that a loss spring constant of 0.2 N / mm or more and 0.3 N / mm or less is more preferable.

[0057] Based on the results of the loss spring constant confirmation, the following drop weight test was further conducted to confirm the characteristics of the substrate of the plate material used in each experimental example. First, a test piece (simulated cushion pad, test piece for drop weight test) of a 60 mm-thick actual rear cushion (a plate-shaped portion to be measured having a thickness of 60 mm) was molded using the substrate of the first plate material. This simulated cushion pad was then used as the REF test piece. Furthermore, a rectangular parallelepiped recess measuring 280 mm in width, 220 mm in the front-rear direction, and 10 mm in thickness was formed on the back side of this molded product directly below the buttocks. Substrates A to D cut into plate shapes that matched this recess were fitted, and the simulated cushion pads with substrates A to D fitted in them were used as test pieces A to D.

[0058] A 50 kg weight was then allowed to freely fall from a position 10 mm above the upper surface (seat surface) of these test specimens, and the acceleration of the weight was measured during the fall and during the rebound process after impacting the seat surface. The free fall of the weight simulated the movement of a user sitting down on a seat. Based on this acceleration and the mass of the weight (multiplying the acceleration by the mass of the weight), the change over time in the load (N) applied to the test specimens by the fall of the weight was calculated.

[0059] The results of these drop weight tests are shown in Figure 9. As shown in Figure 9, for the test specimens of substrate A and substrate D used in Experimental Examples 2 and 5 (Examples 1 and 2), the time (msec) elapsed from when the load applied to the test specimen reached 400 N to when it reached 600 N was longer than that for the REF test specimen (i.e., the slope of the graph was gentler). This indicates that when such substrates are stacked and used in a seat pad, the cushion pad is less likely to cause the user to feel like they are hitting the bottom. Therefore, it is believed that by stacking substrates having a loss spring constant of at least 0.2 N / mm or more and 0.5 N / mm or less and using them in a cushion pad, it is possible to provide a cushion pad and seat that are thin but less likely to cause the user to feel like they are hitting the bottom.

[0060] As described above, it is possible to provide a seat with a thin cushion pad while improving the feeling of bottoming out, and a thin cushion pad while improving the feeling of bottoming out.

[0061] [Another Embodiment] (1) In the above embodiment, the cushion pad 100 has been described with reference to an example in which the second sheet material 22 is disposed in contact with the lower surface of the first sheet material 21 (see FIG. 3 ). However, the cushion pad 100 is not limited to the example in which the second sheet material 22 is disposed in contact with the lower surface of the first sheet material 21. As shown in FIG. 10 , the cushion pad 100 may include another plate material 4 that does not have cushioning properties, such as a metal plate material (e.g., an iron plate), disposed between the first sheet material 21 and the second sheet material 22. FIG. 10 illustrates an example in which the plate material 4 is disposed in contact with the lower surface of the first sheet material 21, and the second sheet material 22 is disposed in contact with the lower surface of the plate material 4. Note that FIG. 10 illustrates a cross section, corresponding to FIG. 3 , of another cushion pad 100 in which the second sheet material 22 is disposed in a different position as described above.

[0062] (2) In the above embodiment, the traveling direction of the vehicle C is described as being forward in the fore-and-aft direction when the seat 200 is used as the reference (see FIG. 4 ). However, the relationship between the traveling direction of the vehicle C and the fore-and-aft direction and their orientation when the seat 200 is used as the reference is not limited to this. The traveling direction of the vehicle C may be backward in the fore-and-aft direction when the seat 200 is used as the reference, or the traveling direction of the vehicle C may be along the width direction when the seat 200 is used as the reference.

[0063] The configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. Furthermore, the embodiments disclosed in this specification are merely examples, and the embodiments of the present disclosure are not limited thereto and can be appropriately modified within the scope of the present disclosure.

[0064] The present disclosure is applicable to seats and cushion pads.

[0065] 10: First pad 100: Cushion pad 11: Seat pad 12: Side pad portion 13: Back pad portion 200: Seat 21: First sheet material 22: Second sheet material 4: Plate material 5: Laminated plate material 51: Slab 52: Slab 91: Seat portion 92: Backrest portion 93: Headrest B: Storage battery C: Vehicle F: Load M: Storage container S: Interior space Sb: Storage space X: Direction Y: Direction Z: Direction t: Plate thickness t1: Plate thickness t2: Plate thickness ta: Plate thickness x: Amount of reduction

Claims

1. A seat comprising a cushion pad that supports a seated user, the cushion pad having a first sheet material made of resin and a second sheet material also made of resin that is laminated on the underside of the first sheet material, the second sheet material being thinner than the first sheet material and having a lower hardness than the first sheet material.

2. The seat according to claim 1, wherein the hardness of the second sheet material is 0.75 to 0.98 times the hardness of the first sheet material.

3. A seat as described in claim 2, wherein the hardness of the first sheet material, measured in accordance with the JASO B408-89 method, is 170N or more and 240N or less, and the hardness of the second sheet material, measured in accordance with the JASO B408-89 method, is 150N or more and 230N or less.

4. The seat according to claim 3, wherein the hardness of the second sheet material is at least 5N less than the hardness of the first sheet material.

5. The seat according to claim 4, wherein the thickness of the second sheet material is 0.10 to 0.40 times the thickness of the first sheet material.

6. A seat as described in claim 5, wherein the thickness of the first sheet material is 30 mm or more and 60 mm or less, and the thickness of the second sheet material is 5 mm or more and 15 mm or less.

7. The seat according to claim 6, wherein the first sheet material and the second sheet material are resin foam.

8. A seat as claimed in any one of claims 1 to 7, wherein the second sheet material is a rectangular plate material with sides of 50 mm and a thickness of 40 mm as a test piece, and the loss spring constant determined by a dynamic spring test in which the test piece is vibrated at a frequency of 0.5 Hz to 10 Hz with an amplitude of 2.5 mm above and below in the thickness direction, centered on a state in which the thickness of the test piece is compressed by 30%. is 0.2 N / mm or more and 0.5 N / mm or less.

9. The air permeability in the thickness direction of the second sheet material is 125 cm when measured in accordance with the air permeability test specified in JIS L 1096. ３ / cm ２ / s or more 150cm ３ / cm ２ 8. The seat according to claim 1, wherein the seat width is equal to or less than 1 / s.

10. A seat equipped with a cushion pad that supports a seated user, said cushion pad having a sheet material formed from resin, said sheet material being a rectangular plate material with a side of 50 mm and a thickness of 40 mm as a test piece, and having a loss spring constant of 0.2 N / mm or more and 0.5 N / mm or less, as determined by a dynamic spring test in which the test piece is vibrated at a frequency of 0.5 Hz to 10 Hz with an amplitude of 2.5 mm up and down in the thickness direction, centered on a state in which the thickness of the test piece is compressed by 30%.

11. A cushion pad comprising: a first sheet material made of resin; and a second sheet material made of resin laminated on the lower surface side of the first sheet material, wherein the second sheet material is thinner than the first sheet material and has a lower hardness than the first sheet material.

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