JP2002065409A - Seat cushion pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat cushion pad improving comfort. SOLUTION: In the pad made of urethane foam, a density ratio of a surface layer A (1 mm thick) located at the seating surface to the core layer E (10 mm thick) located at the middle of the pad is set in a range of 1.13 to 1.60. The rigidity of the surface layer A is higher than that of the core layer E. By this, a loaded pressure is properly distributed to give a user a flat feeling. On the other hand, the core layer has enough elasticity against deformation to give the user elastic feeling at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pad for a seat cushion, and more particularly, to a pad made of a foamed urethane foam material and used as a base material of a seat cushion in a seat of a passenger car or the like. It is about improvement.

[0002]

2. Description of the Related Art For example, an existing seat installed in an occupant compartment of a passenger car or the like is provided with a seat cushion for holding a lower body of the occupant, and a seat which is installed at a rear portion of the seat cushion so as to be tiltable and holds an upper body of the occupant. It is basically composed of a back and a headrest installed above the seat back to protect the head of the occupant.
Among them, for example, in a seat cushion, FIGS.
Urethane foam 1 foamed into the shape shown in
The pad 10 is made of a material such as fabric, synthetic leather, or leather. The pad 10 includes a front support section 14, a rear support section 16
(Center support part) and left and right side support parts 1
8, 18, etc., and their support units 14, 16, 1
At the boundary of 8, a groove 2 for extending and fixing the epidermis to the back side
0 and a hole (not shown) are formed, and a concave portion 2 for accommodating a metal plate, a pipe frame and the like is formed on the back side (lower side).
2 are formed.

The urethane foam 12 forming the pad 10 is formed by injecting a predetermined amount of a urethane material, such as a polyol, isocyanate, or silicone packing agent, into a cavity of a foaming mold and foaming the foam. It is integrally molded into a shape. In particular, since the seat cushion is given most of the weight of the occupant, the pad 1
The characteristic of the urethane foam 12 that forms 0 is comfortable
(Ride comfort) and hold performance.

[0004]

However, in the art,
On the assumption that the sitting comfort is improved, it has been said that the pad 10 used for the seat cushion should preferably be made of urethane foam 12 foamed and formed to have a substantially uniform density as a whole. For this reason, foam molding conditions using a foam mold
By appropriately setting the packing ratio, the temperature of the foaming mold, and the like, the density difference da / de between the density da of the seat surface portion of the pad 10 and the density de of the intermediate portion in the thickness direction of the pad 10 is 1.
05 to 1.10, that is, da = de if possible
(Indicated by broken lines in FIG. 3).

Accordingly, as shown in FIG. 9, when the pressing body 32 is pressed against the seating surface of the pad 10 when measuring the bending deformation characteristics with a compression load tester, 10 m before the compression.
Display lines 24 displayed in a grid pattern at equal intervals of m (FIG. 9A)
As is evident from the deformation of
The surface layer A (first layer) at the seat portion, the core layer E (fifth layer) located at the intermediate portion, and the surface layer A (ninth layer) at the
In each of the first to ninth layers including the layer), the layers are compressed to a substantially uniform thickness (FIG. 9B). That is, in the surface layer A, the thickness a ′ after the deformation is considerably smaller than the thickness a before the deformation, and a ′ <a. On the other hand, the thickness b ′ after the deformation in the core layer E is also the same as that before the deformation. The thickness b is considerably smaller than b, and b ′ <b. Therefore, the bending characteristic a '/
b 'is generally 1.5 or less as shown in Table 1.

However, the pad 10 made of urethane foam 12 having a substantially uniform density as a whole has a
(Rigidity) is also substantially uniform overall (indicated by a broken line in FIG. 5), so even if the core layer E located at the intermediate portion has an appropriate hardness, the surface layer A at the seat portion has a rigidity. Insufficient condition resulted in proper body pressure dispersion. For this reason, when the occupant is seated, the amount of partial depression of the part pressed by the body becomes large, and there is an inherent disadvantage that the sitting comfort is deteriorated. Further, when the occupant's body is tilted with respect to the vehicle body vibration during running or the side G, the surface layer A is easily deformed and the occupant cannot be properly held (so-called “no waist state”). In addition, the occupant is forced to be constantly shaken, and there is also a problem that fatigue, car sickness and the like are likely to occur.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to suitably solve the above-mentioned problems, and the density of the surface layer at the seating portion is set appropriately higher than the density of the core layer located at the intermediate portion. It is an object of the present invention to provide a pad for a seat cushion in which the sitting comfort is improved by increasing the rigidity of the surface layer.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the intended object, the present invention uses a urethane foam foamed to a required thickness as a material and is used for a seat cushion of a passenger car or the like. In the pad, the urethane foam may have a ratio of a density of a surface layer at a seating portion of the seat cushion to a density of a core layer located at a substantially middle portion in a thickness direction within a range of 1.13-1.60. The rigidity of the surface layer is set higher than the rigidity of the core layer.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a seat cushion pad according to a first embodiment of the present invention. The same parts as those of the conventional pad 10 shown in FIGS. 7 and 8 are denoted by the same reference numerals and described.

FIG. 1 is a side sectional view of a pad for a seat cushion according to an embodiment.
Is made of urethane foam 12 which is basically formed in the same outer shape as the conventional pad 10 shown in FIG. That is, the pad 10 is roughly divided into a front support portion 14, a rear support portion 16 (center support portion), and left and right side support portions 18, 18, and a skin portion is provided at a boundary portion between the support portions 14, 16, 18. A groove 20 and a hole (not shown) for tensile fixing to the back side are formed, and a concave portion 22 for accommodating a metal plate, a pipe frame and the like is formed on the back side (lower side). The thickness of the rear support portion 16 to which the weight of the occupant is most given is about 90 mm on the assumption that a metal plate, a pipe frame, or the like is used.

In the pad 10 of the embodiment, when the density da of the surface layer A at the seat surface of the seat cushion is compared with the density de of the core layer E located at a substantially middle portion in the thickness direction (up and down direction), the core Surface layer A from density E of layer E
Is set to be large. For example, taking the rear support portion 16 as an example, as shown in FIG. 2, the density of each layer in the case where the urethane foam 12 is divided into first to ninth layers at a pitch of 10 mm from the surface thereof is shown by a solid line in FIG. It is a numerical value as shown by. That is, the density da of the first layer corresponding to the surface layer A is about 66 kg / cm ³ , and the density de of the fifth layer corresponding to the core layer E is about 56 kg / cm ^3.
And thereby the density da of the surface layer A and the core layer E
Has a density ratio da / de of about 1.18.

Further, in the pad 10 of the embodiment, as is apparent from FIG. 3, the density of the first layer (surface layer A) and the ninth layer (surface layer A) are different from those of the other layers 2, 3, 4, 5, and 5. The density is higher than the densities of the layers 6 and 7, and the densities of the second to eighth layers are substantially the same. Further, as compared with the conventional pad 10 indicated by a broken line in FIG. 3, the density of each layer of 2, 3, 4, 5, 6, 7, 8 in the pad 10 of the embodiment is 2, 3, and The density of the surface layer A (first and ninth layers) in the pad 10 of the embodiment is substantially the same as the density of each layer of 4, 5, 6, 7, and 8, but the density of the surface layer in the conventional pad 10 is It is much larger than A (first and ninth layers).
That is, in the pad 10 of the embodiment, as compared with the conventional pad 10, only the density da of the surface layer A is set to be large.

Also, the first to first pads 10 in the pad 10 of the embodiment are described.
As apparent from FIG. 5, the bending hardness of each of the ninth layers is such that the first layer (surface layer A) and the ninth layer (surface layer A)
The flexural hardness of each of the second to eighth layers is substantially the same as that of the eighth layer. This bending hardness data is 6 mm from the upper surface of each of the test samples shown in FIG.
The test sample 32 of 200 (L) × 25 (W) × 6 (H) mm consisting of the portion of (a) is gradually slid in the direction of the arrow on the upper surface 36 of the measuring jig 34 shown in FIG. The slide amount when the left end of the test sample 32 comes into contact with the 45-degree inclined surface 38 of the measuring jig 34 is measured. The larger the data, the greater the bending hardness. Therefore, in the pad 10 of the embodiment, the rigidity of the first layer (surface layer A) and the ninth layer (surface layer A) whose densities are set to be high are the second to eighth layers including the fifth layer (core layer E). It is higher than the rigidity of each layer.

In the pad 10 of such an embodiment, FIG.
As shown in FIG. 6, when the pressing body 32 is pressed against the seating surface of the pad 10 when measuring the bending deformation characteristic by the compression load tester, the display lines 24 (FIG. As is evident from the deformation of (a), almost no compressive deformation occurs in the first layer and the ninth layer corresponding to the surface layer A in the portion where the compressive deformation is performed. Except for the surface layer A, compression deformation starts from the fifth layer corresponding to the core layer E, and then compresses into the fourth and sixth layers, the third and seventh layers, the second and eighth layers. The deformation proceeds sequentially outward, and finally the second to eighth layers including the core layer E (fifth layer)
Each layer is compressed to a substantially uniform thickness. That is, in the surface layer A, the thickness a ′ after deformation is substantially the same as the thickness a before deformation and a′ａa, whereas in the core layer E, the thickness b ′ after deformation is the thickness before deformation. b ′ <b, which is considerably smaller than b.

[0015]

Table 1 shows the bending characteristics of the conventional pad 10 and the pad 10 of the present invention at the same hardness (25% hardness / 314 cm ² ), and the density ratio da / de is 1.
In the conventional pad 10 of 10, the bending ratio a '/ b' is 1.5 or less. On the other hand, in the pad 10 of the present application, the bending ratio a ′ / when the density ratio da / de is 1.18.
b ′ is 2.0 (the amount of compressive deformation of the core layer E is twice the amount of compressive deformation of the surface layer A), and the bending ratio a ′ / b ′ when the density ratio da / de is 1.30 is 3.0. (3 times the same), the density ratio da / de is 1.5
The deflection ratio a ′ / b ′ at 0 is 4.0 (four times the same).

That is, in the pad 10 of the embodiment, when the occupant is seated, the rigidity of the surface layer A is increased, so that appropriate body pressure distribution can be obtained. Therefore, the weight of the occupant is received over the entire surface layer A. As a result, an appropriate flat feeling is given to the occupant. Moreover, the core layer E
Has sufficient elasticity, so that when the weight of the occupant is given, it is appropriately compressed and deformed to give the occupant an appropriate elasticity. Moreover, as is clear from Table 1, such characteristics become more apparent as the density ratio da / de increases.

(Foam Molding of Pad) The urethane foam 12 having the above-described density distribution structure has a method of controlling a pack ratio at the time of foam molding, a method of controlling a temperature of a foam mold at the time of urethane material injection, and the like. Can be suitably foamed by appropriately applying Among the method, in particular it is one which foam molding by increasing the pack ratio, for example, (a) a polyol, water, intentionally generated amount of CO ₂ that occurs when the isocyanate reacts more By keeping the internal pressure of the foaming mold at the time of foaming high, (b) reducing the out-of-mold release (gas release amount) of generated CO ₂ from the appropriate amount, and increasing the internal pressure of the foaming mold Molding conditions such as holding may be considered. Said
When the urethane foam 12 is foamed under molding conditions such as (a) and (b), the urethane foam 1 to be molded
In No. 2, since the pressure increases toward the surface layer A, the density of the surface layer A increases, and the rigidity of the seating portion increases.

On the other hand, in the above method, the temperature of the foaming mold at the time of injecting the urethane material is set lower than usual (usually, an appropriate temperature is 60 to 67 ° C.,
Since this is set to 40 to 60 ° C.), thermal energy loss occurs during the foaming reaction of the urethane material. Therefore, in the urethane foam 12 to be molded, only the surface layer A in contact with the cavity surface of the foaming mold has a high density. The rigidity of the seat surface is increased.

In the seat cushion pad 10 of the embodiment, which is foam-molded under the foam molding conditions described above, the density da of the surface layer A at the seat surface of the seat cushion is set.
And the density ratio da / de of the density de of the core layer E located at the intermediate portion is about 1.18, so that the rigidity of the surface layer A is higher than that of the core layer E and the sitting comfort can be improved. It became. In other words, since the rigidity of the surface layer A is increased, a suitable body pressure distribution can be performed and an appropriate flat feeling can be given to the occupant. On the other hand, the core layer E has sufficient elasticity and is deformed by compression. It can also give a feeling of elasticity at the same time. Therefore, it is possible to properly hold the occupant's body with respect to the vehicle body vibration and the lateral G during traveling, and the occupant can be stably seated.

In this embodiment, the case where the density ratio da / de of the density da of the surface layer A and the density de of the core layer E is 1.18 is exemplified. Assuming that, the density ratio da / de is 1.
It is desirable to set in the range of 13 to 1.60.

The density ratio d between the surface layer A and the core layer E is d.
The pad 10 whose a / de is set in the range of 1.31 to 1.60 is preferably formed by, for example, a molding method for increasing the pack ratio during foam molding, or a molding method for appropriately lowering the temperature of the foaming mold from an ordinary level. Since molding is possible, there is no need to set complicated molding conditions. In addition, since there is no need to additionally use another device or member, the molding cost does not increase.

[0023]

As described above, according to the seat cushion pad of the present invention, the density of the surface layer at the seat surface portion of the seat cushion and the core layer located at the intermediate portion relate to the urethane foam forming the pad. By setting the density ratio to the density of 1.13 to 1.60 in the range, there is an advantage that the rigidity of the surface layer is higher than the rigidity of the core layer and the sitting comfort can be improved. That is, while the rigidity of the surface layer is increased, the body pressure can be appropriately dispersed to give the occupant an appropriate flat feeling, while the core layer has sufficient elasticity, so that the occupant can be appropriately compressed and deformed. It can also give a moderate elasticity at the same time. Therefore, it is possible to properly hold the occupant's body with respect to the vehicle body vibration and the lateral G during running, and the occupant can be stably seated, and fatigue is reduced even when sitting for a long time. obtain. In addition, the pad in which the density ratio between the surface layer and the core layer is set in the range of 1.13-1.60 can be formed by, for example, a molding method for increasing the packing ratio during foam molding, or appropriately lowering the temperature of the foam mold than usual. Since molding can be suitably performed by a molding method or the like, there is no need to set any complicated molding conditions, and there is no need to use another device or member, so that molding cost does not increase.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a seat cushion pad according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a rear support portion of the pad shown in FIG. 1; when the support portion is divided into nine layers with the same thickness in a thickness direction, a first layer in a seat surface portion is replaced with a surface layer; , The fifth layer located at the intermediate portion is used as the core layer.

FIG. 3 is a graph showing a density distribution of each of first to ninth layers in a pad of an example and a conventional pad.

4A is an explanatory view showing a method for measuring the bending hardness of a pad, and FIG. 4B is a perspective view showing a test sample for measuring bending hardness.

FIG. 5 is a graph showing the bending hardness of each of the first to ninth layers in the pad of the example and the conventional pad.

FIGS. 6A and 6B are explanatory diagrams showing bending deformation characteristics of the pad of the embodiment, in which FIG. 6A shows a state before compression by a pressing body;
(b) shows the state of compression by the pressurizing body.

FIG. 7 is a perspective view of a pad for a seat cushion.

8A is a sectional view taken along line VIIIa-VIIIa in FIG. 7, and FIG. 8B is a sectional view taken along line VIIIb-VIIIb in FIG.

FIG. 9 is an explanatory view showing a bending deformation characteristic of a conventional pad, wherein (a) shows a state before compression by a pressing body,
(b) shows the state of compression by the pressurizing body.

[Explanation of symbols]

 Reference Signs List 10 pad 12 urethane foam A surface layer E core layer da density of surface layer de density of core layer da / de density ratio

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // B29K 75:00 B29K 75:00 105: 04 105: 04 B29L 31:58 B29L 31:58 (72) Inventor Keita Imai 3-136 Imaike-cho, Anjo-shi, Aichi F-term in I-WoW Form Corporation (reference) 3B096 AD07 4F100 AK51A AK51B BA02 BA25 BA26 DJ01A DJ01B GB33 JA13A JA13B JK01 4F204 AA42 AG20 A26 AR06 AR14 EA01 EB01 EF01 EF47 EK13

Claims (4)

[Claims] 1. A pad (10) which is made of urethane foam (12) foamed to a required thickness and is used for a seat cushion of a passenger car or the like, wherein the urethane foam (12) is a seat of the seat cushion. The ratio (da / d) of the density (da) of the surface layer (A) at the surface portion and the density (de) of the core layer (E) located at a substantially intermediate portion in the thickness direction.
e) is set in the range of 1.13-1.60, and the rigidity of the surface layer (A) is set higher than the rigidity of the core layer (E). 2. The pad for a seat cushion according to claim 1, wherein each of the surface layer (A) and the core layer (E) has a thickness of 10 mm. 3. The pad for a seat cushion according to claim 1, wherein the urethane foam (12) is formed by adjusting a packing ratio when the urethane material is foamed. 4. The pad for a seat cushion according to claim 1, wherein the urethane foam is formed by controlling the temperature of a foaming mold at the time of injecting the urethane material.