Patent Application
20200146455
The present disclosure relates to a seat pad.
As seat pads which are structures that form seats, for example, seat pads used for automobile seats are known. A seat pad used for an automobile seat needs to have appropriate hardness and softness in order to stably maintain the sitting posture of a seated occupant while ensuring comfortable sitting, and therefore is made of, for example, foam such as flexible polyurethane foam.
The body temperature of the occupant sitting on the automobile seat is transmitted to the automobile seat. In the case where heat dissipation from the seat pad is insufficient, the transmitted body temperature inevitably makes the seat pad hot. Besides, in the case where the automobile is parked at high outside air temperature such as in the hot weather, the automobile seat reaches high temperature with a temperature increase inside the automobile, which inevitably makes the seat pad hot.
When the seat pad of the automobile seat is hot, the occupant sitting on the automobile seat is constantly exposed to the heat of the seat pad, and feels discomfort. As a result, the riding comfort of the occupant decreases.
To address such situations in which the foam becomes hot, for example, a pillow made of foam and having heat dissipation cavities has been proposed (see PTL 1).
PTL 1: JP 3174096 U
However, for example in the case where heat dissipation cavities are formed to reduce heat in the seat pad made of foam, spaces created inside the seat pad make it difficult to stably maintain the sitting posture of the seated occupant while ensuring comfortable riding. In particular, the riding comfort decreases inevitably.
It could therefore be helpful to provide a seat pad that can dissipate heat efficiently without a decrease in riding comfort of a seated occupant.
A seat pad according to the present disclosure is a seat pad comprising:
a seat pad member forming the seat pad; and
a high ventilation member having higher ventilation property than the seat pad member, wherein
the high ventilation member is embedded in a state of being exposed only to a rear side of the seat pad, and
the high ventilation member is polyurethane foam subjected to membrane removal treatment, the polyurethane foam subjected to membrane removal treatment having a density of 20 kg/m3 to 40 kg/m3 and a number of cells of 45 cells or less per 25 mm.
It is thus possible to provide a seat pad that can dissipate heat efficiently without a decrease in riding comfort of a seated occupant.
In the accompanying drawings:
One of the disclosed embodiments will be described below, with reference to drawings.
As illustrated in
In the seat pad 10 in this embodiment, a high ventilation member 12 higher in ventilation property than a seat pad member forming the seat pad 10 is embedded in a part of the cushion pad 11 of the seat pad 10 except a under-hip portion located under the hips when sitting, in a state of being exposed only to the rear side of the seat pad 10.
Although an example in which the high ventilation member 12 is placed in the cushion pad 11 constituting the seat pad 10 is described in this embodiment, the high ventilation member 12 may be embedded in the back pad (not illustrated) constituting the seat pad 10 in a state of being exposed only to the rear side of the back pad.
In this embodiment, a cushion pad member forming the cushion pad 11 and a back pad member forming the back pad are formed using the same member.
The under-hip portion of the cushion pad 11 is a portion that supports a load on the cushion pad 11. For example in the case where the cushion pad 11 in this embodiment is included in the seat pad 10 installed in an automobile as a seat on which an occupant sits, the under-hip portion of the cushion pad 11 is a part of the cushion pad 11 on which the hips of the seated occupant are located and that includes at least a region between parts on which the ischial tuberosities of the seated occupant are located. The body weight of the occupant sitting on the seat pad 10 is mainly supported by the ischial tuberosities located on a flat surface portion 11a occupying a width direction center portion of the cushion pad 11 and serving as a seat surface.
Herein, “width direction” is a direction of the seat pad 10 installed in the automobile along the automobile width direction, “front-back direction” is a direction of the seat pad 10 installed in the automobile along the automobile front-back direction, and “up-down direction” is a direction of the seat pad 10 installed in the automobile along the automobile up-down direction.
The cushion pad member forming the cushion pad 11 in this embodiment is formed using foamed synthetic resin such as polyurethane foam, e.g. polyurethane foam with a density of 45 kg/m3 to 75 kg/m3. This polyurethane foam is not subjected to membrane removal treatment, and has, for example, a 25% hardness of 200 N/200φ to 300 N/200φ (in accordance with JIS K 6400-2) and a ventilation rate of 100 cc/cm2/sec or less.
The high ventilation member 12 in this embodiment is formed, for example, in a horizontally long rectangular parallelepiped shape approximately across the entire width of the flat surface portion 11a of the cushion pad 11, and contained in a recessed space 13 formed in the cushion pad 11 to correspond to the high ventilation member 12.
The high ventilation member 12 in this embodiment is formed using polyurethane foam with a density of 20 kg/m3 to 40 kg/m3 and more preferably 20 kg/m3 to 30 kg/m3 and a number of cells of 45 cells or less per 25 mm and more preferably 25 cells or less per 25 mm, and preferably 5 cells or more per 25 mm and more preferably 10 cells or more per 25 mm.
As a result of the density of the polyurethane foam being 20 kg/m3 to 40 kg/m3, heat capacity can be reduced while maintaining sitting comfort and riding comfort. As a result of the number of cells of the polyurethane foam being 45 cells or less per 25 mm, a sufficient ventilation rate is ensured, and heat can be dissipated from the seat pad efficiently. If the density of the polyurethane foam is less than 20 kg/m3, sitting comfort and riding comfort are adversely affected. If the density is more than 40 kg/m3, higher heat capacity than in the case of using conventional urethane foam hinders heat dissipation. If the number of cells is more than 45 cells per 25 mm, a sufficient ventilation rate for heat dissipation cannot be ensured.
This polyurethane foam has, for example, a 25% hardness of 50 N/200φ to 90 N/200φ (in accordance with JIS K 6400-2) and a ventilation rate of 150 cc/cm2/sec to 1000 cc/cm2/sec. These are values when the high ventilation member 12 is not inserted in the cushion pad 11 (i.e. in its natural state and not in the below-described compressed state).
The polyurethane foam used as the high ventilation member 12 in this embodiment is polyurethane foam subjected to membrane removal treatment for removing foam membranes, i.e. polyurethane foam with only a skeleton. Such polyurethane foam subjected to membrane removal treatment facilitates replacement of air in a natural ventilation state as compared with polyurethane foam not subjected to membrane removal treatment, thus enabling efficient ventilation. High ventilation property in typical use environments of the seat pad 10 can therefore be ensured.
The polyurethane foam used as the high ventilation member 12 in this embodiment has higher ventilation property than the polyurethane foam used as the seat pad member forming the seat pad 10.
The thickness of the high ventilation member 12 in this embodiment in the up-down direction is preferably 20% or more of the total thickness H (see
The thickness of the high ventilation member 12 in the up-down direction in this embodiment is the thickness when the occupant is not seated on the cushion pad 11. For example, when the thickness of the high ventilation member 12 is 50 mm, the thickness of the cushion pad 11 covering the high ventilation member 12, i.e. the distance h (see
The recessed space 13 in this embodiment is formed in the cushion pad 11 in a horizontally long rectangular parallelepiped shape approximately across the entire width of the flat surface portion 11a to correspond to the shape of the high ventilation member 12, and is open only to the rear side of the cushion pad 11. The high ventilation member 12 in this embodiment is inserted in the recessed space 13 in the seat pad 10 (the cushion pad 11 in this embodiment), in a state of being compressed in a planar view lateral direction of the high ventilation member 12. Thus, the high ventilation member 12 in this embodiment is embedded in the seat pad 10 in a state of being exposed only to the rear side of the seat pad 10.
Herein, the planar view lateral direction of the high ventilation member 12 is a direction orthogonal to the longitudinal direction of the high ventilation member 12 in a planar view. In
The compression ratio when compressing the high ventilation member 12 in this embodiment is, for example, preferably 20% or less of the entire length of the high ventilation member 12 in the planar view lateral direction, and more preferably 5% to 10% of the entire length.
In this embodiment, by compressing the high ventilation member 12 in the planar view lateral direction of the high ventilation member 12 when inserting the high ventilation member 12 into the recessed space 13 in the seat pad 10 (the cushion pad 11 in this embodiment), the high ventilation member 12 is prevented from being deformed, and also prevented from falling off the recessed space 13 of the seat pad 10.
The recessed space 13 in this embodiment is formed in a region on the front end side of the part (the under-thigh portion of the cushion pad 11) of the flat surface portion 11a as the seat surface on which the thighs of the seated occupant are located, i.e. on the front end side of the flat surface portion 11a except the under-hip portion for the occupant.
Hence, in this embodiment, the high ventilation member 12 inserted in the recessed space 13 and embedded in the cushion pad 11 is located in a region on the front end side of the part (the under-thigh portion of the cushion pad 11) of the flat surface portion 11a as the seat surface on which the thighs of the seated occupant are located, i.e. on the front end side of the flat surface portion 11a except the under-hip portion for the occupant. The under-hip portion, in particular the part on which the ischial tuberosities of the seated occupant are located, is a part for supporting the body weight of the occupant, and is a region that affects the riding comfort of the occupant. Accordingly, by providing the high ventilation member 12 in the range of the flat surface portion 11a except the part on which the ischial tuberosities of the occupant are located, the riding comfort of the occupant is least affected.
More specifically, the position of the high ventilation member 12 is preferably within a region extending from the front end of the cushion pad 11 and having a length of 40% of the length L (see
The number of high ventilation members 12 may be two or more.
Thus, in the seat pad 10 in this embodiment, the high ventilation member 12 higher in ventilation property than the seat pad member forming the seat pad 10 and made of polyurethane foam subjected to membrane removal treatment with a density of 20 kg/m3 to 40 kg/m3 and a number of cells of 45 cells or less per 25 mm is embedded in a state of being exposed only to the rear side of the seat pad.
The seat pad 10 in this embodiment having such a structure can dissipate heat from the rear side of the cushion pad 11 efficiently, even in the case where the seat pad 10 becomes hot as a result of the body temperature of the occupant sitting on the seat pad 10 being transmitted to the seat pad 10 or as a result of the automobile seat reaching high temperature with a temperature increase inside the automobile when the automobile is parked at high outside air temperature such as in the hot weather. That is, the seat pad 10 in this embodiment can efficiently dissipate heat in the seat pad 10 made of polyurethane foam which is a material that is hard to cool and easily becomes hot, through the high ventilation member 12 of the cushion pad 11.
As a result of the thickness of the high ventilation member 12 being 20% or more of the total thickness of the cushion pad 11 and the high ventilation member 12 at the position where the high ventilation member 12 is embedded, heat in the cushion pad 11 can be dissipated efficiently while ensuring riding comfort. Hence, heat can be dissipated from the seat pad further efficiently.
The high ventilation member 12 in this embodiment is located on the front end side of the part (under-thigh portion) of the flat surface portion 11a as the seat surface on which the thighs of the seated occupant are located. More specifically, the high ventilation member 12 in this embodiment is located within a region extending from the front end of the cushion pad 11 and having a length of 40% of the length of the cushion pad 11 in the front-back direction. The movement of the under-thigh portion of the flat surface portion 11a is greater than the movement of the under-hip portion during running, for example. Since the frequency of compression and release of the cushion pad 11 is high, the pumping effect is facilitated. This contributes to significant effect of discharging hot air inside the cushion pad 11 including the high ventilation member 12 to the outside. Hence, heat can be dissipated from the cushion pad 11 efficiently, with it being possible to cool the cushion pad 11 easily.
Thus, the cushion pad 11 in the seat pad 10 in this embodiment is easy to cool, and therefore the seat pad 10 can be kept from becoming hot. This prevents situations in which the seated occupant feels discomfort as a result of the seat pad 10 becoming hot and consequently the sitting comfort of the occupant and the riding comfort of the occupant decrease. Particularly when cooling the automobile interior by an air conditioner, the automobile interior can be cooled efficiently, and the cooling effect can be enhanced. The seat pad 10 in this embodiment is therefore more effective in the case where the automobile is parked in the hot weather or the like and the automobile seat reaches high temperature.
Moreover, in this embodiment, the high ventilation member 12 is embedded in the cushion pad 11 on the front end side of the part (under-thigh portion) of the flat surface portion 11a on which the occupant's thighs are located. There is no space inside the cushion pad 11 made of foam in the under-hip portion and in particular the part on which the ischial tuberosities of the seated occupant are located, and polyurethane foam is provided in all of the part (under-thigh portion) of the flat surface portion 11a as the seat surface on which the occupant's thighs are located and the under-hip portion. This prevents situations in which, due to a space formed inside the cushion pad 11, it is difficult to stably maintain the sitting posture of the seated occupant while ensuring comfortable sitting. The sitting comfort of the occupant and the riding comfort of the occupant are therefore not impaired.
Although the high ventilation member 12 embedded in the cushion pad 11 is exposed only to the rear side of the cushion pad 11 in this embodiment, the high ventilation member 12 may communicate with the front side (upper surface) of the cushion pad 11 through one or more narrow communication holes.
Cushion pads for a seat pad according to the present disclosure were produced experimentally (Examples), and their temperature changes with time were compared with those of Comparative Examples.
A cushion pad of Example a has a structure in which the high ventilation member 12 is embedded in the under-thigh portion of the cushion pad (see
In Example a, the high ventilation member 12 embedded in the cushion pad is exposed only to the rear side of the cushion pad (see
A cushion pad of Comparative Example X is made only of polyurethane foam as a cushion pad member, without a high ventilation member of Examples.
Changes in the temperature (° C.) inside the cushion pad of each of Example a (density: 30 kg/m3), Example b (density: 21 kg/m3), Example c (density: 40 kg/m3), and Comparative Example X with time (min) are illustrated in a graph (
As can be seen from
Thus, each of the cushion pads of Example a using the high ventilation member 12 with a density of 30 kg/m3, Example b using the high ventilation member 12 with a density of 21 kg/m3, and Example c using the high ventilation member 12 with a density of 40 kg/m3 reached a lower temperature than the cushion pad of Comparative Example X without a high ventilation member (Example a: 41.4° C., Example b: 41.1° C., Example c: 43.1° C., against Comparative Example X: 46.6° C.), involving an initial rapid temperature decrease (Example a: 10.9° C., Example b: 12.1° C., Example c: 9.0° C., against Comparative Example X: 7.6° C.). In particular, Example a with a density of 30 kg/m3 and Example b with a density of 21 kg/m3 achieved a considerable temperature decrease of more than 15° C. from the initial temperature.
Next, temperature changes (initial temperature: 60 (° C.), after 15 min) of the cushion pad 11 (having the high ventilation member 12 embedded in a part other than the under-hip portion so as to be exposed only to the rear side of the cushion pad) of the seat pad 10 according to the present disclosure in the case of changing the number of cells of the high ventilation member 12 (see
In
As illustrated in
In
As illustrated in
As Comparative Examples, a sample (Comparative Example G) with a thickness of about 70% of the total thickness, a number of cells of 63 cells per 25 mm, and a density of 45 kg/m3 and a sample (Comparative Example H) in which the same high ventilation member 12 as Example a is included without being exposed to the rear side of the cushion pad 11, i.e. contained within the cushion pad 11 (mold urethane), were used to examine changes in the temperature (° C.) inside the cushion pad 11 with time (min).
As can be seen from Table 3, the temperature decrease of the cushion pad 11 was 6.2 (° C.) in elapsed time 0 to 10 (min) and 2.5 (° C.) in elapsed time 10 to 15 (min) in Comparative Example G, and 7.2 (° C.) in elapsed time 0 to 10 (min) and 3.8 (° C.) in elapsed time 10 to 15 (min) in Comparative Example H. The temperature decrease after 15 (min) was 8.7 (° C.) in Comparative Example G, and 11.0 (° C.) in Comparative Example H.
That is, in the case where the number of cells was more than 45 cells per 25 mm and the density was more than 40 kg/m3 (Comparative Example G has a number of cells of 63 cells per 25 mm and a density of 45 kg/m3), the temperature decrease of the cushion pad 11 after 15 min was about 8.7 (° C.). This demonstrates that the temperature decreased significantly in Example a whose temperature decrease after 15 min was about 15.2 (° C.), Example b whose temperature decrease after 15 min was about 15.1 (° C.), Example c whose temperature decrease after 15 min was about 12.8 (° C.), sample A whose temperature decrease after 15 min was about 15 (° C.), sample B whose temperature decrease after 15 min was about 13 (° C.), sample D whose temperature decrease after 15 min was about 13 (° C.), and sample E whose temperature decrease after 15 min was about 18 (° C.).
In the case where the high ventilation member 12 was not exposed to the rear side of the cushion pad 11 (Comparative Example H), the temperature decrease of the cushion pad 11 after 15 min was about 11.0 (° C.). This demonstrates that the temperature decreased significantly in Example a whose temperature decrease after 15 min was about 15.2 (° C.), Example b whose temperature decrease after 15 min was about 15.1 (° C.), Example c whose temperature decrease after 15 min was about 12.8 (° C.), sample A whose temperature decrease after 15 min was about 15 (° C.), sample B whose temperature decrease after 15 min was about 13 (° C.), sample D whose temperature decrease after 15 min was about 13 (° C.), and sample E whose temperature decrease after 15 min was about 18 (° C.).
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-228964 | Nov 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/042090 | 11/22/2017 | WO | 00 |
