JP2578163B2 - Cushion body for seat - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin seat cushion suitable for a vehicle seat such as an automobile.

[Related Art] In recent years, there has been an increasing demand for seat cushions used in automobiles to have not only improved sitting comfort but also reduced thickness. Urethane foams, which are suitable for mass production and have relatively good ride comfort, are frequently used for cushion bodies for automobiles. However, in the case of a commonly used urethane foam having a thickness of 100 mm or less, the cushion performance test and the sensory evaluation relating to riding comfort are significantly deteriorated. This is because reducing the foam thickness reduces the amount of deflection in the compression direction, so the impact at the moment of sitting is not sufficiently absorbed and a feeling of bottoming occurs, and the vibration impact transmitted from the vehicle body during running is reduced. This is because the transmission increases.

[Problems to be Solved by the Invention] Conventionally, in order to obtain a somewhat satisfactory ride comfort even with a thin sheet, resin foam used for a cushion body is made to have a high resilience, or a foam of a different hardness is used. Attempts have been made to use foams and the like, but in all cases, when the foam thickness was 100 mm or less, particularly about 60 mm, good results could not be obtained in the cushion performance test and sensory evaluation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cushioning member for a seat which can provide a good ride comfort even if the thickness is sufficiently smaller than a conventional pad thickness.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, the following two factors affect the ride comfort, such as the feeling of bottoming due to the impact at the time of sitting and the transmission of the vibration impact during traveling. The first urethane foam has low rebound resilience for shock absorption, and cushioning for shock absorption and spring function. A second urethane foam having a higher rebound resilience than the first urethane foam was used, and these two types of urethane foams were laminated in the thickness direction over the entire cushion body.

[Operation] In the seat cushion body having the above-described structure, the first urethane foam reduces the feeling of bottoming due to the impact at the time of sitting and the transmission of vibration and shock during traveling, and the second urethane foam has an appropriate stroke feeling. Is obtained. When these two types of foams were laminated, good results were obtained in the sensory test evaluation and the cushion performance test even if the total thickness was reduced to within 100 mm.

[Example of the invention] Example 1 An upper layer 2 and a lower layer 3 are laminated in the thickness direction of a front seat cushion 1 of an automobile shown in Fig. 1. The upper layer 2 is made of a low rebound resilient first urethane foam (thickness: 20 mm) formed by foaming so that the rebound resilience is 12% and the hysteresis loss ratio is 39.1%. The lower layer 3 is made of a second urethane foam (having a thickness of 40 mm) having a rebound resilience of 69%, and the lower layer 3 extends in the thickness direction over the entire lower surface of the upper layer 2 as shown in FIG. It is laminated. The measurement method of rebound resilience is JISK
6401 (the same applies to Examples 2 and 3 described below and Conventional Products 1 and 2).

Example 2 As in the cushion body 1 illustrated in FIG. 2, a low rebound resilience first urethane foam (thickness: 40 mm) having a rebound resilience of 10% and a hysteresis loss rate of 53.2% is used for the lower layer portion 3. A second urethane foam (thickness: 20 mm) having a rebound resilience of 65% is laminated on the upper layer 2 over the entire upper surface of the lower layer 3 in the thickness direction.

Embodiment 3 Similar to the laminated structure of the cushion body 1 shown in FIG. 1, the upper layer 2 has a rebound resilience of 15% and a hysteresis loss rate of 78.
% Low-elasticity first urethane foam (thickness 10mm)
Further, a hot urethane foam (thickness: 50 mm) having a rebound resilience of 40% was laminated on the lower layer 3.

Conventional product 1 Low-elasticity urethane foam single layer with 12% rebound resilience and 39.1% hysteresis loss.
mm.

Conventional product 2 Consists of only a single layer of urethane foam having a high rebound resilience of 69% and a foam thickness of 60 mm.

Each of the above-described Examples 1 to 3 has a multilayer structure of two types of urethane foams having different rebound resiliences. A vibration absorbing effect is obtained, and the second urethane foam having a high rebound resilience provides an appropriate spring feeling.
Good ride comfort was obtained even when the thickness was reduced to 100 mm or less, especially around 60 mm.

FIG. 3 shows a comparison of cushioning performance between Examples 1 to 3 and conventional products 1 and 2, and shows cushioning properties of a front seat of an automobile based on sensory evaluations by a plurality of leveled subjects. . The shock absorbing performance shown in FIG. 4 indicates the maximum value of the change in acceleration when the pressure plate is freely dropped on the seat cushion. The smaller the G value, the better the shock absorbing performance. ing.

In practicing the present invention, two or more first urethane foams and second urethane foams may be alternately stacked.

[Effects of the Invention] According to the present invention, good ride comfort can be obtained even when the foam thickness is as thin as 100 mm or less, and the seat and backrest of an automobile seat are made thinner and lighter. There is also a great effect on the above.

[Brief description of the drawings]

FIG. 1 is a perspective view of a part of a cushion body showing a first embodiment of the present invention, FIG. 2 is a perspective view of a part of a cushion body showing a second embodiment of the present invention, and FIG. FIG. 4 is a diagram comparing the cushion performance of the example product of the present invention and the conventional product, and FIG. 4 is a diagram comparing the shock absorbing performance.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takuro Higuchi 622 Kitakase, Saiwai-ku, Kawasaki-shi, Kanagawa Japan, in the Kawasaki Plant of Hatsujo Co., Ltd. (56) References JP-A-63-166630 (JP, A) Showa 57-65650 (JP, U)

Claims (2)

(57) [Claims] 1. A first urethane foam having a low rebound resilience, and a first urethane foam having a higher rebound resilience than the first urethane foam and laminated in the thickness direction over the entire upper or lower surface of the first urethane foam. A seat cushion body comprising: a second urethane foam. 2. The method according to claim 1, wherein the total laminated thickness of the first urethane foam and the second urethane foam is 10 cm or less and used for an automobile seat. Cushion body for seat.