Vehicle interior materials and seat backrest panels.

Abstract

Invention details;

Description

Vehicle interior materials and seat back panels

[0001] The present application relates to a vehicle interior material and a seat back panel using the same.

[0002] For example, Patent Document 1 discloses a vehicle seat. The seat back of this vehicle seat includes a seat backboard, and a cover member is sewn to a rear cover portion of the seat backboard. Patent Document 1 describes that the rear cover portion of the seat backboard is made of a resin material with a Shore hardness of greater than 50, making it possible to sew the cover portion.

[0003] Japanese Patent Application Laid-Open No. 2019-104403

[0004] Components having a structure in which a skin material is sewn onto a vehicle interior material made of resin or the like are used in various locations inside a vehicle cabin. One example is a vehicle seat in which a cover is sewn onto a resin seat backboard, as disclosed in Patent Document 1. In the case of such components having a structure in which a skin material is sewn onto a vehicle interior material, the vehicle interior material used typically requires high rigidity.

[0005] Furthermore, in the case of vehicle interior materials to which upholstery materials are sewn, ease of sewing is also important. For example, if an attempt is made to sew upholstery materials to a substrate that is difficult to sew, such as a resin material, a sewing machine with extremely high penetration power is required, and the sewing speed must be slowed down during sewing, resulting in reduced work efficiency. Furthermore, the lifespan of the needles used in the sewing machine is also shortened. Therefore, from the perspective of reducing manufacturing costs, it is desirable for vehicle interior materials to which upholstery materials are sewn to be easy to sew.

[0006] However, rigidity and ease of sewing in vehicle interior materials are in a trade-off relationship, and increasing the rigidity of a vehicle interior material makes it difficult to sew the covering material, making it difficult to achieve both. In this regard, although Patent Document 1 uses a sewable material with a Shore hardness of 50 or more for the rear cover portion of the seat backboard, it does not solve the difficulty of sewing the rear cover portion, which is made of a resin material.

[0007] In view of the above problems, an object of the present application is to provide a vehicle interior material and a seat back panel that take into consideration both rigidity and ease of sewing.

[0008] A vehicle interior material according to one embodiment of the present application is configured so that, when Shore hardness is H [Hs], thickness is d [mm], and bending rigidity is K [MPa·mm4], an index X shown in the following formula (1) is smaller than an upper limit value set in accordance with the ease of sewing required for the vehicle interior material.

[0009] Here, the vehicle interior material may be configured so that the index X is greater than a lower limit value set in accordance with the rigidity required for the vehicle interior material.

[0010] A vehicle interior material according to another embodiment of the present application is configured so that the index X shown in the above formula (1) is smaller than 54,000. Here, the vehicle interior material may be configured so that the index X is further larger than 3,500.

[0011] The vehicle interior materials according to these embodiments may have a Shore hardness H [Hs] value of 50 or more. The vehicle interior materials may also be made using one or more of fibers, felt, foamed resin, and hollow resin structures.

[0012] A seat back panel according to one aspect of the present application is formed using the vehicle interior material according to any one of the aspects of the present application.

[0013] The index X of a vehicle interior material is represented by the Shore hardness H, thickness d, and bending rigidity K, and can be used as a value indicating the ease of sewing. That is, by setting the Shore hardness H and bending rigidity K within an allowable range, and further setting the index X within a set range, the vehicle interior material and seat back panel can be made to have both the necessary rigidity and ease of sewing.

[0014] FIG. 1 is a diagram showing the results of a piercing test on samples of a plurality of substrates. FIG. 2 is a diagram showing values ​​indicating the properties of samples of a plurality of substrates in a table. FIG. 3 is a diagram showing the relationship between an index X of a vehicle interior material according to an embodiment of the present application and ease of sewing. FIG. 4 is a perspective view schematically showing the overall configuration of a vehicle seat according to an embodiment of the present application. FIG. 5 is a front view schematically showing a portion of the back side of a seat back panel according to an embodiment of the present application.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be simplified or omitted.

[0016] Embodiment. Materials that can be used for the substrate of the vehicle interior material according to this embodiment include, for example, fibers, felts such as compressed felt or knitted felt, foamed resins such as urethane foam, and hollow resin structures (e.g., honeycomb structures). The substrate may also be configured by laminating two or more of these materials. The substrate may also be configured by covering these materials with a skin material. Examples of skin materials include synthetic leather containing PVC (polyvinyl chloride) or nonwoven fabric. Synthetic leather containing PVC includes synthetic leather made solely of PVC and synthetic leather primarily composed of PVC. Synthetic leather primarily composed of PVC includes, for example, PVC coated with a resin such as nylon or polyurethane. The skin material may also be synthetic leather containing other materials, such as PP (polypropylene), fibers such as nonwoven fabric and woven fabric, and natural leather.

[0017] The substrate is required to have a required rigidity. Specifically, the substrate preferably has a Shore hardness of 50 or more, and in some cases, a higher hardness is desirable. The above-mentioned substrate materials are subjected to a hardening treatment as necessary so as to have the required rigidity. Various methods for increasing the rigidity of these materials are well known, and a description thereof will be omitted here.

[0018] On the other hand, increasing the rigidity of the substrate reduces the ease of sewing to the substrate. Therefore, in the case of a substrate to which a skin material is to be sewn, it is not sufficient to simply make the substrate have a higher rigidity. The substrate as a vehicle interior material according to this embodiment has the necessary rigidity while also ensuring ease of sewing.

[0019] The sewability of a substrate can be confirmed by a puncture test. FIG. 1 shows the results of a puncture test on two samples, substrate A and substrate B. In FIG. 1, the vertical axis represents the puncture load [N], and the horizontal axis represents the puncture stroke [mm]. This puncture test was conducted using a universal testing machine (Instron, Model 3344) and a puncture jig (Imada, TKS250N). The test speed was 50 mm / min, the stroke was 0 to 10 mm, and the sample size of each substrate was 60 mm x 60 mm.

[0020] The base material B indicated by the dashed line is a base material made of a resin having high rigidity. In the case of this base material B, the piercing load is particularly high until the piercing stroke exceeds 4 mm, i.e., until the piercing jig penetrates the base material B, and the frictional resistance after penetration is also relatively large. In other words, it is considered to be a material that is relatively difficult to sew.

[0021] On the other hand, substrate A, indicated by the solid line, has a smaller piercing load overall than substrate B, and even at a stroke of around 4 mm where the piercing load is at its maximum, it is less than half of that of substrate B. Furthermore, the piercing load after reaching its maximum is also relatively low.

[0022] It can be considered that the easier a substrate is to penetrate and the smaller the frictional resistance after penetration, the easier it is to sew. In other words, the integral value of the curve showing the change in piercing load [N] from stroke 0 to 10 [mm] in Figure 1, i.e., the area value of the part surrounded by the vertical axis, horizontal axis, and curve showing piercing load [N] (hereinafter simply referred to as "area value"), is easier to sew as it is smaller, and more difficult to sew as it is larger. In this way, the area value in Figure 1 can be used as a value indicating the sewability of a substrate. In other words, it can be said that the smaller this area value is, the easier it is to sew a substrate, and the larger it is, the more difficult it is to sew.

[0023] Figure 2 is a table showing characteristic values ​​of samples of multiple substrates. The table in Figure 2 shows values ​​indicating the ease of sewing (i.e., the above-mentioned area values) obtained as a result of a puncture test performed on each substrate sample. In Figure 2, substrates 2 and 12 are the same as substrates A and B in Figure 1, respectively. Substrates 1 to 11 are substrates for vehicle interior materials according to the present application, and substrates 12 to 14 are conventional substrates used as vehicle interior materials.

[0024] In Figure 2, conventional substrates 12 to 14 have high rigidity, but a large area value indicating ease of sewing, and are therefore judged to have poor sewability. Substrate 11 has slightly lower rigidity, but is a material that is sufficiently easy to sew. This substrate 11 can be used by being reinforced, if necessary, depending on the rigidity required for the part in which it is used. Substrates 1 to 10 all have a Shore hardness of 50 or more, and are sufficiently rigid for vehicle interior materials, while also having a sufficiently low area value indicating ease of sewing, making them easy to sew. In other words, they are considered to be materials more suitable for vehicle interior materials.

[0025] The inventors of the present application have repeatedly carried out puncture tests on such various substrates, and after extensive research, have found that the index X shown in the following formula (1) using Shore hardness has a correlation with the above-mentioned area value, i.e., the ease of sewing of the substrate. Here, "H" is the Shore hardness of the substrate [Hs], "d" is the thickness of the substrate [mm], and "K" is the bending rigidity [Mpa mm４ ].

[0026] 3 is a diagram showing the relationship between index X and sewability. In FIG. 3, the horizontal axis represents index X, and the vertical axis represents sewability, i.e., area value. From FIG. 3, it can be seen that the sewability value approximates the value of a linear function of index X.

[0027] In this embodiment, a lower limit value α and an upper limit value β are set for the index X within a range that can ensure the required rigidity and ease of sewing. The base material as a vehicle interior material according to this embodiment ensures the required rigidity and ease of sewing by making the index X satisfy the following formula (2).

[0028] The index X indicates the ease of sewing, with a smaller value indicating easier sewing and a larger value indicating more difficult sewing. Meanwhile, the index X is a value obtained by multiplying the Shore hardness H, thickness d, and bending stiffness K by values ​​that correlate with stiffness. The smaller this value, the lower the stiffness, and the larger this value, the higher the stiffness. Therefore, the range indicated by the index X can be set with its lower limit α set to a value corresponding to the required stiffness and its upper limit β set to a value corresponding to the required ease of sewing. The index X also includes the thickness d of the base material as a parameter. Therefore, for example, if there is a requirement for the thickness d of the base material, the lower limit α and upper limit β can be set within a range that satisfies the required thickness d.

[0029] Furthermore, from the results of a puncture test including the substrate shown in Fig. 2, the inventors of the present application have derived that the index X of the substrate should more preferably have a lower limit α of 3500 and an upper limit β of 54000. That is, the index X of the substrate as a vehicle interior material according to this embodiment more preferably satisfies the following formula (3):

[0030] As explained above, by providing a vehicle interior material that satisfies formula (2) or (3), it is possible to obtain a vehicle interior material that is easy to sew while ensuring the necessary rigidity. Use of this vehicle interior material eliminates the need for a sewing machine with high penetration power, improving the work efficiency of sewing vehicle interior materials and extending the life of the sewing machine needles. This can therefore contribute to reducing the cost of parts used inside the vehicle cabin.

[0031] In the above embodiment, the index X of the vehicle interior material is described as being within the range defined by the lower limit α and the upper limit β, or within the range greater than 3500 and less than 54000. However, the vehicle interior material may have an index X that is less than the upper limit β or 54000, and an index X of less than the lower limit α or 3500 is also acceptable.

[0032] 4 is a side view schematically illustrating an example of a vehicle seat to be placed in a vehicle. The base material as a vehicle interior material according to this embodiment is used as a material for a seat back panel 10 of a vehicle seat 1, for example, as shown in FIG.

[0033] The vehicle seat 1 in Figure 4 includes a seat back 2, a seat cushion 3, and a headrest 4. The seat back 2 is supported at the rear end of the seat cushion 3. The seat back 2 is for supporting the back of the occupant. The headrest 4 is disposed at the upper end of the seat back 2. The headrest 4 is for supporting the head of the occupant. The seat back 2 includes a seat back main body portion (not shown). The seat back main body portion may include a cushioning material such as a pad, a support frame, etc. A seat back panel 10 is provided on the back side of the seat back main body portion.

[0034] 5 is a front view schematically showing a portion of the rear side of the seat back panel 10. As shown in Fig. 5, a seat fabric 20 is sewn to the outer periphery of the seat back panel 10 at a sewing position 11. The portion of the front side of the seat back main body that is not covered by the seat back panel 10 is covered by the seat fabric 20 sewn to the seat back panel 10.

[0035] In this embodiment, the material for the seat fabric 20 is not particularly limited. However, because the seat fabric 20 covers the portion of the seat that comes into contact with passengers, it is desirable to select a material for the seat fabric 20 taking into consideration the tactile feel and luxurious appearance. Specifically, the seat fabric 20 may be made of, for example, synthetic leather containing PVC (polyvinyl chloride), nonwoven fabric, or the like. Synthetic leather containing PVC includes synthetic leather made solely of PVC and synthetic leather primarily composed of PVC. Synthetic leather primarily composed of PVC includes, for example, PVC coated with a resin such as nylon or polyurethane. Furthermore, the seat fabric 20 may be made of, for example, synthetic leather containing other materials such as PP (polypropylene), fibers such as nonwoven fabric and woven fabric, natural leather, or the like.

[0036] By using the vehicle interior material of this embodiment as the seat back panel 10, it is possible to easily sew the seat fabric 20 while ensuring the rigidity required for the seat back panel 10. This makes it possible to improve the efficiency of the sewing work in the manufacture of the seat back panel 10, thereby reducing the manufacturing cost of the seat back panel 10.

[0037] The vehicle interior material according to the present embodiment is not limited to being applied to the seat back panel 10, but can also be suitably used for other parts installed inside a vehicle, which are configured by sewing a skin material to a base material that is a vehicle interior material. Specifically, in addition to seat back panels, the vehicle interior material can be used as a material that configures all or part of, for example, a dashboard, an instrument panel, door trim, pillar trim, and a rear parcel shelf.

[0038] In the above embodiments, when the number, quantity, amount, range, etc. of each element is mentioned, the examples of the seat back panel and vehicle seat of this application are not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in this embodiment are not necessarily essential to the configuration of the seat back panel and vehicle seat of this application unless otherwise specified or clearly specified in principle.

[0039] REFERENCE SIGNS LIST 1 Vehicle seat 2 Seat back 3 Seat cushion 4 Headrest 10 Seat back panel 11 Sewing position 20 Seat fabric

Claims

DEPCT691. A vehicle interior material is configured in such a way that the index X, determined by the following formula (1), is less than the upper limit determined according to the required degree of seamability for the vehicle interior material: [Formula 1] Index X = HxKxd2••••(1) where Shore hardness is denoted by H(Hs), thickness is denoted by d(mm) and bending stiffness is denoted by K(Megapascals•mm4).

2. A vehicle interior material according to claim 1 in which the index X is greater than the lower limit determined according to the required degree of seamability for the vehicle interior material.

3. Vehicle interior materials which are configured in such a way that the index X, determined by the following formula (1), is less than 54000: [Formula 2] Index X = HxKxd2••••(1) where Shore hardness is denoted by H(Hs), thickness is denoted by d(mm) and bending stiffness is denoted by K(Megapascals•mm4).

4. Vehicle interior materials according to Reputation 3 where the index X is greater than 3500.

5. Vehicle interior materials according to any of Reputations 1 through 4 where the Shore hardness H(Hs) is 50 or greater. 6.

7. Seat back panels which are made using one or more of the vehicle interior materials specified in Claims 1 through 5;

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