Seat and cushion pad

Abstract

To provide a seat having a cushion pad made thinner while improving a bottom-touch feeling, and to provide a cushion pad made thinner while improving a bottom-touch feeling.SOLUTION: A seat 200 comprises a cushion pad 100 for supporting a seated user, and the cushion pad 100 has a sheet material 21 formed from a resin. A loss spring constant of the sheet material 21, obtained by a dynamic spring test of using as a test piece, a plate material of a rectangle with one side of 50 mm and a thickness of 40 mm, and vibrating at an upper and lower vibration amplitude of 2.5 mm in a thickness direction about a center where the thickness of the test piece is compressed by 30%, and at a frequency of 0.5 Hz or more and 10 Hz or less is 0.20 N / mm or more and 0.35 N / mm or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[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 The following is the description: 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 automobile seat cushion pads are made thin, resulting in 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 joined 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-280855 A [Patent Document 2] Japanese Patent Application Publication No. 09-070330 Summary of the Invention [Problem to be solved by the invention]

[0005] In vehicles such as automobiles, it is necessary to ensure sufficient interior space for passengers. In addition, in vehicles equipped with storage batteries, such as electric vehicles (EVs) and hybrid vehicles (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 passengers. 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 tends to give the user a feeling of 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). In particular, pads with a two-layer structure such as that in Patent Document 2 have problems in that the cost of materials for manufacturing them increases and the labor required to construct the two-layer structure increases, resulting in an increase in processing costs. Therefore, it is desired to provide a seat with a thinner cushion pad while improving the feeling of hitting the bottom, and a thinner cushion pad 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. [Means for solving the problem]

[0008] The seat according to the present disclosure for achieving the above object comprises: A cushion pad is provided to support a seated user, The cushion pad has a sheet material formed of resin, The sheet material is a rectangular plate material with sides of 50 mm and a thickness of 40 mm used as a test piece, and the loss spring constant obtained 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 0.20 N / mm or more and 0.35 N / mm or less.

[0009] In order to achieve the above object, the cushion pad according to the present disclosure comprises: A sheet material formed of resin is provided, The sheet material is a rectangular plate material with sides of 50 mm and a thickness of 40 mm used as a test piece, and the loss spring constant obtained 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 0.20 N / mm or more and 0.35 N / mm or less. [Effects of the Invention]

[0010] 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. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of a seat according to the present embodiment. [Figure 2] FIG. 2 is a perspective view of the cushion pad according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] 1 is an explanatory diagram of a vehicle equipped with a seat according to an embodiment of the present invention. [Figure 5] FIG. 2 is an explanatory diagram of a test piece for dynamic spring testing in the examples. [Figure 6] FIG. 1 is an explanatory diagram of a dynamic spring test. [Figure 7] This is the measurement result of the loss spring constant. [Figure 8] These are the results of the drop weight test. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Description of the embodiment) A seat and a cushion pad according to an embodiment of the present disclosure will be described with reference to the drawings.

[0013] 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.

[0014] In FIG. 1, the width direction (left-right direction) as seen by a user seated on 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.

[0015] As shown in FIGS. 2 and 3, the cushion pad 100 has a sheet material 21 made of resin. The sheet material 21 is a rectangular (square) plate material with sides of 50 mm and a thickness of 40 mm, which serves as a test piece (dynamic spring test piece). The test piece is compressed 30% (compressed 12 mm in this example) to a thickness of 30 mm. The test piece is vibrated in the thickness direction of the test piece with an amplitude of 2.5 mm up and down at a frequency (frequency) of 0.5 Hz to 10 Hz. The loss spring constant determined by the dynamic spring test is 0.20 N / mm to 0.35 N / mm. FIG. 2 is a perspective view of the cushion pad 100 as seen from the diagonal front. FIG. 3 is a cross-sectional view taken along the arrows III-III in FIG. 2.

[0016] 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 sensation 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.

[0017] The seat 200 and the cushion pad 100 will be described in detail below.

[0018] 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. As an example, the seat 200 may include a seat portion 91 on which the user places their buttocks, a backrest portion 92 against which the user leans their back, 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 seen from the backrest portion 92 is the front (front, forward direction), and the side of the backrest portion 92 seen from the seat portion 91 is the rear (rear, rear direction). In the following explanation, the front-to-rear direction will be explained based on this positional relationship.

[0019] The seat 200 may have, inside its cover, a member (seat pad) that serves as a cushion conforming 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 cushion member inside the seat portion 91 that supports a user seated on the seat portion 91.

[0020] As shown in FIGS. 2 and 3, the cushion pad 100 includes a pad 10.

[0021] The pad 10 may have a seat pad 11 having a 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.

[0022] The seat pad 11 is placed below the portion of the seat 200 where the user's buttocks would be located. The seat pad 11 may be a plate-like member that is thick in the vertical direction. The thickness of the seat pad 11 is, for example, 50 mm or more and 120 mm or less. 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.

[0023] The 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 pad 10 is a resin foam. The resin foam is preferably polyurethane, but may be formed from other resins. The pad 10 may be formed, for example, by injection foam molding.

[0024] The 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 sheet material 21 is, for example, 30 mm or more and 70 mm or less.

[0025] The hardness of the 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 JASO B408-89, which is a method of 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 sheet material 21 be 170 N or more and 240 N or less when the thickness is 50 mm.

[0026] The sheet material 21 is a rectangular plate material with sides of 50 mm and a thickness of 40 mm used as a test piece, and the loss spring constant obtained 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 or more and 0.35 N / mm or less.

[0027] By setting the loss spring constant of the seat material 21 to be 0.20 N / mm or more and 0.35 N / mm or less, it is possible to improve the feeling of hitting the bottom of the seat 200 (see Figure 1) while also achieving a reduction in the thickness of the cushion pad 100 (see Figure 2), particularly the seat pad 11.

[0028] In the following description, the improvement in the bottoming out feeling of the seat 200 will be simply referred to as the improvement in the bottoming out feeling. Also, the thinning of the cushion pad 100 (seat pad 11) may be simply referred to as the thinning.

[0029] The thickness of the sheet material 21, i.e., the thickness of the central portion of the seat pad 11, is sufficient if it is 70 mm or less. In order to thin the cushion pad 100, it is preferable to make it 60 mm or less. With the cushion pad 100, the user does not feel like they are hitting the bottom, even if the cushion pad is thinned, due to the effect of the sheet material 21 improving the feeling of hitting the bottom.

[0030] FIG. 4 shows a vehicle C equipped with a seat 200 equipped with a cushion pad 100. FIG. 4 illustrates a case where 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 accommodation space Sb for the accommodation container M that accommodates the storage battery B, which is disposed below the seat 200, can be ensured.

[0031] (Example) The following describes the improvement of the bottoming feeling and the thinning of the seat and cushion pad based on examples.

[0032] In this example, differences in bottoming out sensation were evaluated using sheet materials (each of which had a polyurethane resin foam as the base material) with different loss spring constants. The differences in bottoming out sensation were evaluated by a drop weight test, as described below.

[0033] First, a method for measuring the loss spring constant (dynamic spring test) of a sheet material (substrate) will be described. Fig. 5 shows an explanatory diagram of a dynamic spring test specimen 5 for measuring the loss spring constant. Fig. 5 is a side view of the dynamic spring test specimen 5. Fig. 6 shows an explanatory diagram of a method for measuring the loss spring constant using the dynamic spring test specimen 5. The dynamic spring test specimen 5 is formed from the same substrate as the sheet material to be evaluated.

[0034] As shown in FIG. 5, the dynamic spring test specimen 5 is a rectangle (square) with sides of 50 mm and a thickness of 40 mm. As shown in FIG. 6, when measuring the loss spring constant, the dynamic spring test specimen 5 is first clamped between fixtures 51 and 52, and, for example, one fixture 51 is displaced to compress the thickness of the dynamic spring test specimen 5 by 30% (in this example, 12 mm). With the dynamic spring test specimen 5 compressed in this manner, the other fixture 52 is vibrated by a vibration generator 56 (vibrator), thereby applying vibration to the dynamic spring test specimen 5. Then, the change in the load applied to the fixture 51 by the vibrating dynamic spring test specimen 5 is measured by a load cell 55 attached to the fixture 51. The loss spring constant of the dynamic spring test specimen 5 (the characteristic of the loss spring constant with respect to frequency) can be determined from the frequency of the vibration applied by the vibration generator 56 and the change in load measured by the load cell 55. In this embodiment, the amplitude of the vibration applied to the dynamic spring test specimen 5 by the vibration generator 56 is ±2.5 mm, and the frequency (frequency) is in the range of 0.5 Hz to 10 Hz.

[0035] In Experimental Example 1 (Example 1), a substrate having a loss spring constant (loss spring constant in the vibration frequency range of 0.5 Hz to 10 Hz) measured as described above of 0.20 N / mm to 0.35 N / mm was used as the sheet material. The hardness of the sheet material in Experimental Example 1 was 205 N. As described in the above embodiment, the hardness in this example is a value measured in accordance with the JASO B408-89 method. The shape of the test piece used to measure this hardness was a rectangular parallelepiped with dimensions of 300 mm x 300 mm (a rectangle with each side measuring 300 mm) and a thickness of 50 mm.

[0036] In Experimental Example 2 (Comparative Example 1), a substrate having a loss spring constant measured as described above of more than 0.35 N / mm and not more than 0.80 N / mm was used as the sheet material. The hardness of the sheet material in Experimental Example 2 was 219 N. The loss spring constant profiles of the sheet materials in Experimental Examples 1 and 2 are shown in FIG.

[0037] The difference in bottoming out feeling was evaluated by a drop weight test as follows: In the drop weight test, a test piece (simulated cushion pad, drop weight test piece) was used, which was molded as a full-sized rear cushion with a thickness of 60 mm in the center part (seat material part) of the seat pad part (the part to be measured was a plate-like part with a thickness of 60 mm).

[0038] A 50 kg weight was then allowed to freely fall from a position 10 mm above the top surface of these test specimens (the seating surface of the seat pad) onto the center of the seat pad (the part made of sheet material), and the acceleration of the weight was measured during the fall and during the process of rebounding after impacting the seating surface. 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. The free fall of the weight simulated the action of a user sitting down on a seat.

[0039] In this example, the results of the drop weight test are evaluated as follows. First, the evaluation is based on the premise that the typical range of the load applied to the cushion pad (the seat material portion) when the user is seated in the seat is 400 N or more and 600 N or less. Based on this premise, an evaluation criterion can be established that, when the user sits in the seat, if the time it takes for the reaction force of the load applied to the cushion pad to reach the range of 400 N or more and 600 N or less is short, the user is likely to feel a bottoming-out sensation, and if this time is long, the user is unlikely to feel a bottoming-out sensation. According to this criterion, in the drop weight test, if the time it takes for the load applied to the cushion pad to reach the range of 400 N or more and 600 N or less is long, in other words, if the slope of the load with respect to elapsed time in the drop weight test (the slope until the load reaches the range of 400 N or more and 600 N or less) is small, the bottoming-out sensation can be evaluated as being reduced. In other words, in the drop weight test, if the slope of the graph with respect to elapsed time is gentle, the test piece can be evaluated as being unlikely to feel a bottoming-out sensation.

[0040] The results of these drop weight tests are shown in Figure 8. As shown in Figure 8, for the test piece (sheet material) of Experimental Example 1, the time (msec) until the load applied to the test piece reaches the range of 400N to 600N and the time (msec) elapsed from when the load applied to the test piece reaches 400N to when it reaches 600N are longer than those for the test piece of Experimental Example 2, and the slope of the graph with respect to elapsed time is gentler. Therefore, it can be seen that the cushion pad equipped with the sheet material of Experimental Example 1 is less likely to give the user a feeling of hitting the bottom.

[0041] In this way, it was found that by providing a cushion pad with a sheet material having a loss spring constant of at least 0.20 N / mm or more and 0.35 N / mm or less, it is possible to provide a cushion pad and seat that is thin enough to be 70 mm or less in thickness (60 mm in Experimental Example 1) and yet does not cause the user to feel like they are hitting the bottom.

[0042] A cushion pad equipped with a sheet material having a loss spring constant of at least 0.20 N / mm to 0.35 N / mm can achieve both a thin thickness and an improved bottoming feeling with a single-layer structure, without requiring a complex structure such as a two-layer structure for the seat pad portion. This makes it possible to inexpensively manufacture cushion pads and seats equipped with the same.

[0043] 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.

[0044] [Another embodiment] (1) 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.

[0045] (2) In the above embodiment, the cushion pad 100 has been described with an example in which the central portion of the seat pad 11 is made of only one layer of the sheet material 21. However, this embodiment does not exclude the case in which the central portion of the seat pad 11 is made of two or more layers. For example, the central portion of the seat pad 11 may have a structure in which the sheet material 21 and another sheet material that is thinner than the sheet material 21 (for example, having a thickness of 30% or less of the thickness of the sheet material 21) are laminated together.

[0046] It should be noted that the embodiments disclosed in this specification are merely examples, and the embodiments of the present disclosure are not limited to these, and can be modified as appropriate within the scope of the purpose of the present disclosure. [Industrial Applicability]

[0047] The present disclosure is applicable to seats and cushion pads. [Explanation of symbols]

[0048] 10: Pad 100: Cushion pad 11: Seat pad 12: Side pad section 13: Back pad 200 seats 21: Sheet material 5: Dynamic spring test specimen 51: Fixture 52: Fixture 55: Load cell 56: Vibration generator 91: Seat part 92: Backrest 93: Headrest B: Storage battery C: Vehicle M: Storage container S:Indoor space Sb: Storage space X: Direction Y: Direction Z: Direction

Claims

1. A cushion pad is provided to support a seated user, The cushion pad has a sheet material formed of resin, The sheet material is a rectangular plate material with sides of 50 mm and a thickness of 40 mm used as a test piece, and the loss spring constant obtained 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 from a state in which the thickness of the test piece is compressed by 30% is 0.20 N / mm to 0.35 N / mm.

2. 2. The seat according to claim 1, wherein the thickness of the sheet material is 30 mm or more and 70 mm or less.

3. A sheet material formed of resin is provided, The sheet material is a rectangular plate material with sides of 50 mm and a thickness of 40 mm used as a test piece, and the cushion pad has a loss spring constant of 0.20 N / mm or more and 0.35 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 or more and 10 Hz or less with an amplitude of 2.5 mm up and down in the thickness direction from a state in which the thickness of the test piece is compressed by 30%.

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