Cushion body provided with linear body, and method for manufacturing same

Abstract

Provided is a cushion body which can be used for a steering heater or steering sensor, an interior heater, and an interior sensor, and which is excellent in temperature rising properties and detection accuracy and is excellent in mountability. This cushion body comprises: a base material made of a foamed body; an adhesive layer provided on an outermost surface of the base material; and a linear body partially embedded in the base material. The linear body is in contact with the adhesive layer. The adhesive layer has a substantially flat shape. In the base material, a section in which the linear body is embedded has the same density as a section in which the linear body is not embedded. In the base material, an outermost surface opposite to the surface on which the adhesive layer is provided is a skin layer. In the linear body, a plurality of strands are horizontally wound or twisted, and the foamed body enters between the plurality of strands.

Description

Cushion body with a linear body, and method for manufacturing the same

[0001] The present invention relates to, for example, a heater unit for warming the wheel portion of a steering wheel used in an automobile, a ship, etc., a sensor unit for detecting the temperature and grip of a steering wheel, a heater unit installed in the interior of a vehicle such as an armrest or a door trim, and a method for manufacturing the same.

[0002] Conventionally, in order to warm the driver's hand in cold weather, it has been proposed to attach a heater unit to the wheel portion of a steering wheel. The steering wheel consists of a wheel portion, a spoke portion, and a boss portion. The wheel portion is formed from a wheel core material in which a metal core is covered with a urethane resin or the like, and a covering material made of synthetic resin, fiber products, leather, or the like. The heater unit is installed between the wheel core material and the covering material and is connected to a lead wire passed through the spoke portion and the boss portion to be powered.

[0003] As a heater unit installed in a steering wheel, for example, a heater unit in which a cord-shaped heater is wired in a predetermined pattern shape on a base material as shown in Patent Document 1 is known. Here, as the base material, various foamed resin sheets, foamed rubber sheets, rubber sheets, non-woven fabrics, woven fabrics, etc. are disclosed. In addition, as particularly related technologies, for example, Patent Documents 2 to 7 can be cited. Further, as other related technologies, for example, Patent Document 8 can be cited.

[0004] Japanese Patent No. 4,202,071: Krabé Japanese Unexamined Patent Application Publication No. 2014-143,175: Krabé Japanese Unexamined Patent Application Publication No. 2014-209,444: Krabé International Publication WO2014 / 104,000: Toyoda Gosei, Krabé International Publication WO2017 / 026,217: Krabé International Publication WO2023 / 204,022: Krabé International Publication WO2024 / 142,835: Krabé DE102017008496B4: I.G.B

[0005] For example, the heater units described in Patent Documents 2 to 7 have a base material where the thickness of the area where the cord-shaped heater is wired is thinned to conform to the shape of the cord-shaped heater, resulting in a flat shape. With such a heater unit, when it is incorporated into a steering wheel, the unevenness caused by the cord-shaped heater is usually not visible, and the user does not feel any discomfort when operating the steering wheel. However, modern heater units also require ease of installation. The heater units described in Patent Documents 2 to 7 are difficult to incorporate into a steering wheel on their own, and require separate fixing members, thus posing a problem in terms of ease of installation.

[0006] The heater unit described in Patent Document 8 above is formed using a two-component foam material to create a base material, and after the base material is formed, adhesive tape or hook-and-loop fasteners are placed on the base material as fixing members. Another form described is insert molding, in which mounting members such as covers or door trims are placed inside the mold used to form the base material and formed integrally. However, due to the nature of the manufacturing method, cavities or through holes are always formed in the base material, which can result in an unintended heat insulating structure and difficulties in heating. Furthermore, when such a heater unit is used as a sensor unit, the distortion of the base material shape due to cavities or through holes causes the position of the sensor wire to shift, resulting in difficulties in detection accuracy. Problems caused by the distortion of the base material shape due to cavities or through holes also occur when used as a heater unit, resulting in a poor tactile feel due to the shift in the position of the heater wire. In addition, insert molding is a manufacturing method that cannot be used for mounting members that are sensitive to heat, thus limiting its applicability.

[0007] The present invention was made to solve the problems of the prior art, and its objective is to provide a cushion body that can be used in steering heaters, steering sensors, interior heaters, and interior sensors, and that has excellent heating properties, detection accuracy, and ease of installation, as well as a method for manufacturing the same.

[0008] To achieve the above objective, the cushion body according to the present invention comprises a base material made of foam, an adhesive layer provided on the outermost surface of the base material, and a linear body partially embedded in the base material, wherein the linear body is in contact with the adhesive layer. Furthermore, the adhesive layer is thought to be generally flat in shape. Furthermore, the apparent density of the base material is thought to be approximately the same in the vicinity of the linear body and in the distant portion of the linear body. Furthermore, the outermost surface of the base material opposite to the surface on which the adhesive layer is provided is thought to be a skin layer. Furthermore, the linear body is thought to consist of multiple strands that are wound or twisted together, with the foam penetrating between the multiple strands. Furthermore, the linear body is thought to be a heater wire or a sensor wire. Furthermore, the area on which the adhesive layer is provided is considered an adhesive section, in which the linear body is in contact with the adhesive section, and it is thought that there are two or more adhesive sections. Furthermore, the outermost surface of the base material other than the adhesive section is thought to be a skin section. The method for manufacturing a cushion body according to the present invention comprises the steps of: arranging an adhesive layer and a linear body in a mold; and forming a base material integrally with the adhesive layer and the linear body in the mold.

[0009] According to the present invention, an adhesive layer is provided on the outermost surface of the substrate, and since the adhesive layer and the linear body are in contact, the number of components that interfere with the function of the linear body is minimized. That is, when the linear body is a heater wire, the substrate does not function as an insulating material, and it exhibits excellent heat transfer or radiation functions in one planar direction. Also, when the linear body is a sensor wire, the substrate does not function as a shielding material, and it has excellent detection accuracy in one planar direction.

[0010] Furthermore, because the adhesive layer is provided on the base material, it can be attached to the mounting surface without the use of additional components, resulting in excellent ease of attachment.

[0011] This is a schematic diagram showing a method for manufacturing a cushion body according to Embodiment 1 of the present invention. This is a plan view showing the structure of a cushion body according to Embodiment 1 of the present invention. This is a schematic cross-sectional view showing an enlarged view of the main part of a cushion body according to Embodiment 1 of the present invention. This is a schematic cross-sectional view showing a cushion body according to Embodiment 1 of the present invention embedded in a steering wheel. This is a schematic cross-sectional view showing a conventional cushion body embedded in a steering wheel. This is a diagram showing the configuration of a press-type cushion body manufacturing apparatus used in the present invention. This is a partial perspective view showing how a linear body is wired into a predetermined pattern shape in the cushion body of the present invention. This is a partially cutaway side view showing an example of a linear body used in the present invention. This is a partially cutaway side view showing an example of a linear body used in the present invention. This is a partially cutaway side view showing an example of a linear body used in the present invention. This is a partially cutaway perspective view showing a cushion body according to the present invention embedded in a steering wheel. This is a schematic diagram showing a method for manufacturing a cushion body according to Embodiment 2 of the present invention. This is a plan view showing the structure of a cushion body according to Embodiment 2 of the present invention. This is a schematic cross-sectional view showing an enlarged view of the main part of a cushion body according to Embodiment 2 of the present invention. This is a schematic cross-sectional view showing a cushion body according to Embodiment 2 of the present invention embedded in a steering wheel.

[0012] Embodiments of the present invention will be described below with reference to the drawings. These embodiments illustrate examples in which the cushioning body of the present invention is applied to a steering heater.

[0013] In this invention and specification, density refers to apparent density. Apparent density is calculated by considering the air bubbles present inside the substrate as part of the substrate's volume, and is calculated by dividing the mass of the substrate by the apparent volume of the substrate (the volume determined from the external shape of the substrate, including the internal air bubbles). Apparent volume refers to the volume including the air bubbles. The mass and apparent volume of the substrate can be measured by arbitrarily cutting out a predetermined part of the substrate. Apparent density can also be measured according to JIS K7222 "Foamed plastics and rubber - Method for determining apparent density".

[0014] First, Embodiment 1 will be described with reference to Figures 1 to 3. The configuration of the linear body 1 in Embodiment 1 will be described first. The linear body 1 in Embodiment 1 has the configuration shown in Figures 8 to 10. In this embodiment, the linear body 1 functions as a heater wire. First, the core wire 3 is formed of an aromatic polyamide fiber bundle with an outer diameter of approximately 0.14 mm. Four conductor strands 5a, which are hard tin-filled copper alloy wires with a strand diameter of 0.06 mm, are arranged and wound spirally around the outer circumference of the core wire 3 at a pitch of approximately 0.65 mm. As shown in Figures 8 and 9, an insulating coating 5b is formed around the conductor strands 5a. As shown in Figure 10, the insulating coating 5b is formed of an inner layer 5c made of polyurethane resin and an outer layer 5d made of polyamide-imide resin. The inner layer 5c of the insulating coating 5b is formed to be a layer with a thickness of 4 μm by applying polyurethane varnish around the conductor strands 5a and drying it. Next, the outer layer 5d was formed by applying polyamide-imide varnish to the outer circumference of the inner layer 5c and drying it to form a layer with a thickness of 4 μm. The outer circumference of the core wire 3, around which the conductor strands 5a are wound, is covered with an insulating layer 9. The edge layer 9 is formed by extruding a polyester resin containing a flame retardant to a thickness of 0.085 mm. The finished outer diameter of the above-described linear body 1 is 0.45 mm, and the outer diameter excluding the insulating layer 9 is approximately 0.28 mm. The core wire 3 is effective in that it increases flexibility and tensile strength. It is also possible to use multiple conductor strands aligned or twisted together without using the core wire 3.

[0015] Next, with reference to Figures 1, 6, and 7, a method for manufacturing the base material 11 and cushion body 31 in which the linear body 1 having the above configuration is embedded will be described. First, as shown in Figure 7, there is a press jig 15, and a plurality of locking mechanisms 17 are provided on this press jig 15. As shown in Figure 7, the locking mechanism 17 is equipped with a pin 19, which is inserted from below into a hole 21 drilled in the press jig 15. A locking member 23 with a needle-shaped tip is attached to the upper part of the pin 19 so as to be movable in the axial direction and is constantly biased upward by a coil spring 25. A temporary release film 18 with holes in the locations corresponding to the locking mechanisms 17 is placed on the press jig 15. Then, as shown by the dashed lines in Figure 7, the linear body 1 is wired in a predetermined pattern shape while hooking it onto the locking members 23 of these plurality of locking mechanisms 17.

[0016] Returning to Figure 6, a press plate 27 is positioned above the multiple locking mechanisms 17 so as to be able to move up and down. The linear body 1 is wired in a predetermined pattern shape by hooking it onto the locking members 23 of the multiple locking mechanisms 17, and an adhesive layer 22 is placed on top of it. The adhesive layer 22 is composed of a release film 19 for application and an adhesive layer 20, and here the adhesive layer 20 is placed facing downwards. In this state, the press plate 27 is lowered to adhere the adhesive layer 22 to the linear body 1 in a substantially uniform manner. When the press plate 27 is lowered to perform the adhesion, the locking members 23 of the multiple locking mechanisms 17 move downward against the biasing force of the coil spring 25.

[0017] By performing the above procedure, a temporary fixing member 32 can be created in which the following layers are stacked from the bottom: temporary release film 18, linear body 1, adhesive layer 20, and release film 19 for application. The adhesive layer 20 and release film 19 for application are collectively referred to as the adhesive layer 22.

[0018] Next, the temporary fixing member 32 created by the method described above is placed in the mold 61, which has been heated to a predetermined temperature, with the release film 19 for application facing downwards, as shown in Figure 1. After the temporary fixing member 32 is placed in the mold 61, the temporary release film 18 is peeled off from the temporary fixing member 32, leaving the linear body 1 exposed inside the mold 61. Then, the lid frame 62 is placed over the mold 61 to form a sealed space, and the raw material for creating the base material 11 is injected into the mold 61 through an inlet (not shown). A known raw material can be used to create the base material 11, but if a urethane foam base material is to be created, it is advisable to use a two-component mixed raw material of isocyanate liquid and polyol liquid. Furthermore, although Figure 1 shows a release film 19 for application that is smaller than the inner diameter of the mold 61, it is preferable to make the release film 19 conform to the inner shape of the mold 61, as this prevents the release film 19 from shifting when the base material is injected. Other possible methods include temporarily fixing the release film 19 and the mold 61 with double-sided adhesive tape, or using magnetic or suction force for temporary fixing.

[0019] By performing the above work, a cushion body 31 as shown in Figure 2 can be obtained. Figure 3 is a cross-sectional view showing an enlarged view of the main part of Figure 2. The part of the base material 11 corresponding to reference numeral 64 in Figure 3 is the embedded part of the linear body 1 (the vicinity 64 of the linear body), and the part of the base material 11 corresponding to reference numeral 65 is the unembedded part of the linear body 1 (the distant part 65 of the linear body). Alternatively, the vicinity 64 of the linear body is the part of the base material 11 from the outer circumference of the linear body 1 to half the diameter of the wire, and the distant part 65 of the linear body refers to the other part of the base material 11. The base material 11 is foamed and formed in a mold having a protrusion, such as inside the mold 61 that encloses the exposed linear body 1, so that it is formed in a predetermined shape without any part being compressed. That is, because the density of the embedded vicinity 64 of the linear body 1 and the unembedded distant part 65 of the linear body 1 are seemingly the same, the linear body 1 does not move due to compressive stress, and the fixing force of the linear body 1 is excellent. The apparent density referred to here is the density of the base material 11, including voids, and the apparent density can be measured according to JIS K7222. Furthermore, as shown in the cross-sectional view of Figure 3, fixing a certain outer circumference of the linear body 1 with the base material 11 firmly fixes the linear body 1 and prevents the wiring pattern from shifting. The certain outer circumference of the linear body 1 referred to in this paragraph is less than 360 degrees and more than 200 degrees when the cross-section of the linear body 1 is viewed as an approximate circle. Also, as shown in Figure 3, the base material 11 penetrates into a part between the linear body 1 and the adhesive layer 22, and at the same time, a very small part of the linear body 1 is exposed from the base material 11 and in contact with the adhesive layer 20. As a different method, for example, if a method in which compressive stress remains in the base material is used, the linear body may lift up due to changes over time, which may adversely affect the tactile feel, but in this embodiment, the linear body 1 does not lift up due to changes over time, which is preferable. Furthermore, when linear bodies are embedded in a substrate using a compression method, only a portion of the substrate becomes densely packed, resulting in hardness and an unpleasant sensation. In this embodiment, however, the density of the substrate 11 is uniform throughout, and there is no unpleasant sensation upon contact, which is preferable. Note that the uniformity of the overall density referred to here means considering the substrate 11 excluding its surface.In the manufacturing method described in Patent Document 2, for example, variations in the thickness and hardness of the finished unit sometimes occurred, resulting in difficulties with winding and grip during or after assembly into the final product. This embodiment is preferable because it allows for stable production of the thickness and hardness of the cushion body 31, thereby improving quality and productivity.

[0020] The cushion body 31 is exposed from the base material 11 such that a certain outer circumference of the linear body 1 is in contact with the adhesive layer 20 of the adhesive layer 22. In this paragraph, the certain outer circumference of the linear body 1 refers to a value greater than 0 degrees and less than or equal to 160 degrees when the cross-section of the linear body 1 is viewed as approximately a circle. Therefore, when the linear body 1 is a heater wire, the base material 11 does not function as an insulating material, and excellent heat transfer or radiation functions can be achieved in one planar direction. Also, when the linear body 1 is a sensor wire, the base material 11 does not function as a shielding material, and excellent detection accuracy can be achieved in one planar direction.

[0021] In addition, the cushion body 31 is equipped with an adhesive layer 22, and can be attached to various locations simply by peeling off the release film 19 used for attachment. For example, when the cushion body 31 is used as a heater or sensor for a steering wheel, the adhesive layer 20 of the adhesive layer 22 is used to attach it to the steering wheel core material 77 or the steering wheel covering material 78. Due to the structure of the cushion body 31, the heater wire or sensor wire is exposed on the adhesive layer 22 side, so attaching it to the steering wheel covering material 78 provides superior heater or sensor functionality, but it is preferable to design it according to the product purpose.

[0022] Furthermore, the adhesive layer 22 of the cushion body 31 is generally flat, which prevents the cushion body 31 from peeling off due to unevenness in the adhesive layer 22 when attaching it to the mounting surface. Here, a thickness variation within a range of approximately ±10% can be said to be generally flat, and is essentially a nearly constant thickness. Also, if the degree of thickness variation is within a range where the user does not perceive any unevenness visually or tactilely, it can also be said to be generally flat.

[0023] The outermost surface opposite the surface to which the adhesive layer 22 is provided is a skin layer, which has a smooth and pleasant appearance. By providing such a skin layer, it is possible to prevent fragmentation and peeling that may occur when the surface of the cushion body 31 has fine irregularities, and thus it has excellent durability.

[0024] As shown in Figure 2, the ends of the linear body 1 are pulled out and connected to lead wires 35, and the linear body 1, temperature control device 39, and connector (not shown) are connected by these lead wires 35. The temperature control device is placed on the linear body 1 and controls the temperature of the cushion body 31 by the heat generated by the linear body 1. The above connector is then connected to the vehicle's electrical system (not shown). The cushion body 31 with the above configuration is installed on the steering wheel 71 in the state shown in Figure 11. The steering wheel 71 consists of a wheel portion 72, a spoke portion 73, and a boss portion 74, and the cushion body 31 is installed between the wheel core material 77 and the covering material 78 of the wheel portion 72. In this embodiment, the cushion body 31 functions as a heater unit.

[0025] When the cushion body 31 according to the present invention is installed on the steering wheel 71 in the state shown in Figure 11, its cross-section becomes as shown in Figure 4. The upper part of Figure 4 is the user's fingertips, the part of the cushion body 31 on the user's fingertip side is the covering material 78 (steering wheel surface), and the part opposite it is the wheel core material 77. The cushion body 31 also contains a base material 11, a linear body 1 (used as both a heater and a sensor wire), and an adhesive layer 20. In this case, the linear body 1 contained within the cushion body 31 of the present invention is installed on the user's fingertip side. By installing it in this way, when the linear body 1 is driven as a heater, the heating characteristics are particularly good, and it can be treated as a heater unit with excellent convenience. The distance from the linear body 1 to the outermost surface (the surface that the user contacts) is defined as the sensing correlation distance 67, and the distance from the linear body 1 to the wheel core material 77 is defined as the noise correlation distance 68. In this case, it is preferable that the sensing correlation distance 67 is short, as the shorter it is, the better the detection performance. Furthermore, a long noise correlation distance 68 is preferable, as the longer it is, the less noise interferes with detection. In conventional examples such as the aforementioned Patent Document 5, the cross-section is as shown in Figure 5, and the sensing correlation distance 67 is longer and the noise correlation distance 68 is shorter than that of the present invention, meaning that the detection performance is inferior. This is because, when the linear body 1 wired to the conventional base material 11 is installed as shown in Figure 4, the irregularities caused by the linear body 1 appear on the surface of the covering material 78, causing discomfort when in contact, so the linear body 1 was installed as shown in Figure 5 as a compromise. However, with the cushion body 31 according to the present invention, even if the linear body 1 is installed as shown in Figure 4, the overall density of the base material 11 is uniform, so there is no discomfort when in contact, and for the reasons mentioned above, the detection performance is also improved, making it particularly preferable. Furthermore, since the base material 11 contains voids, and these voids contribute to heat insulation, it is even more preferable that the linear body 1 is installed on the user's fingertip side relative to the entire base material 11. In addition, while a long noise correlation distance 68 is preferable, a low relative permittivity is also preferable. The relative permittivity is affected by the amount of voids and the material, and the lower the value, the more noise can be removed. The substrate 11 of the present invention is particularly preferable because the amount of voids can be designed by appropriately adjusting the foaming rate, which reduces the relative permittivity and leads to a reduction in the amount of noise that interferes with detection.

[0026] Next, Embodiment 2 will be described with reference to Figures 12 to 15. Note that components common to Embodiment 1 are given the same reference numerals as in Embodiment 1, and detailed explanations will be omitted. In this embodiment, two linear bodies 1 are provided, each functioning as a heater / sensor combined wire and a guard wire. The configuration of each linear body 1 is the same as in Embodiment 1. Temporary fixing members 32 are created for each of the two linear bodies 1 in the same manner as in Embodiment 1.

[0027] Referring to Figure 12, a method for manufacturing a base material 12 and a cushion body 33 in which two temporary fixing members 32 (two linear bodies 1) are embedded will be described. The labels TOP and BOTTOM in Figure 12 refer to the front and back directions of each member and are not actually engraved on the members. First, in step (a), two temporary fixing members 32 made in the same manner as in Embodiment 1 are prepared. Next, in steps (b) and (c), with the release film 19 for application facing downwards, they are placed inside the mold 61 heated to a predetermined temperature and on the back side of the lid frame 62, respectively. Here, double-sided adhesive tape or the like may be used to fix the temporary fixing members 32 to the lid frame 62. After each is placed, the temporary release film 18 is peeled off from the temporary fixing members 32, leaving the linear bodies 1 exposed. Subsequently, in step (c'), the lid frame 62 to which the temporary fixing member 32 is fixed is turned upside down, and in step (d), the mold frame 61 and the lid frame 62 are fitted together. After fitting them together to form a sealed space, the raw liquid for creating the base material 12 is injected into the mold frame 61 from the injection port 63.

[0028] By performing the above work, a cushion body 33 as shown in Figure 13 can be obtained. Figure 14 is a cross-sectional view showing an enlarged view of the main part of Figure 13. The portion of the base material 12 corresponding to reference numeral 64 in Figure 14 is the embedded portion of the linear body 1 (proximal portion 64 of the linear body), and the portion of the base material 12 corresponding to reference numeral 65 is the unembedded portion of the linear body 1 (remote portion 65 of the linear body). Alternatively, the proximal portion 64 of the linear body is the portion of the base material 12 from the outer circumference of the linear body 1 to half the diameter of the wire, and the remote portion 65 of the linear body refers to the remaining portion of the base material 12. In this embodiment, one of the two linear bodies 1 functions as a heater / sensor combined wire, and the other functions as a guard wire. With this configuration, when installed on the steering wheel 71 as shown in Figure 11, it is possible to reduce the number of parts while achieving good detection performance, which is particularly preferable.

[0029] As shown in Figure 13, the area on the cushion body 33 where the temporary fixing member 32 is embedded becomes an adhesive section 41, and the other outermost surface area becomes a skin section 42. By simply peeling off the release film 19 for application to the adhesive section 41, the adhesive layer 20 is exposed, making it possible to attach it to various locations. The skin section 42 is smooth and has a pleasant texture. By providing such a skin section 42, it is possible to prevent fragment peeling that may occur when the surface of the cushion body 33 has fine irregularities, and it has excellent durability. The adhesive layer 22 refers to the part that is configured in a planar shape, and the adhesive section 41 refers to the part that encompasses the linear body 1 and the adhesive layer 22. For example, when the cushion body 33 is used as a heater or sensor for a steering wheel, the adhesive section 41 is used to attach it to the steering wheel core material 77 or the steering wheel covering material 78. Due to the structure of the cushion body 33, the heater wire or sensor wire is exposed on the adhesive section 41 side, so attaching it to the steering wheel covering material 78 provides superior heater or sensor functionality, but it is preferable to design it according to the product purpose. Furthermore, the fact that the adhesive section 41 is provided on two or more surfaces on the base material 12 improves the versatility of how it can be attached to various locations. In addition, the fact that the adhesive section 41 is provided on two or more surfaces on the base material 12 means that the linear body 1 is also wired near two or more surfaces of the cushion body 33, which has the advantage of being able to provide heater or sensor functionality in two or more directions. In Embodiment 2, the adhesive section 41 is provided on the front and back surfaces, but it may be provided on either the front or back surface or on one side, or it may be provided on the entire circumference. Alternatively, the cushion body 33 may have a gable roof or hip roof shape, and the adhesive section 41 may be provided on a predetermined surface of the roof.

[0030] When the cushion body 33 according to the present invention is installed on the steering wheel 71 in the state shown in Figure 11, its cross-section becomes as shown in Figure 15. The upper part of Figure 15 is the user's fingertips, the part of the cushion body 33 on the user's fingertips side is the covering material 78 (steering surface), and the part opposite it is the wheel core material 77. The cushion body 33 also contains a base material 12, a linear body 1 (a heater wire / sensor wire combined wire and a guard wire), and an adhesive layer 20. In this case, one of the linear bodies 1 contained within the cushion body 33 is installed on the user's fingertips side and functions as a heater wire / sensor wire combined wire. The other linear body 1 functions as a guard wire. By installing it in this way, when the linear body 1 is driven as a heater, the heating characteristics are particularly good, and it can be treated as a heater unit with excellent convenience. Furthermore, the distance from the linear body 1 to the outermost surface (the surface that the user contacts) is defined as the sensing correlation distance 67, and the distance from the linear body 1 to the wheel core material 77 is defined as the noise correlation distance 68. In this case, it is preferable that the sensing correlation distance 67 be short, as the shorter it is, the better the detection performance. It is also preferable that the noise correlation distance 68 be long, as the longer it is, the less noise interferes with detection. In conventional examples, the sensing correlation distance 67 was longer than that of the present invention, resulting in inferior detection performance. This is because, in conventional cases, when the linear body 1 wired to the base material 12 is installed on the surface side, the irregularities caused by the linear body 1 appear on the surface of the covering material 78, causing discomfort when contacted. As a compromise, the linear body 1 was installed on the back side. However, in the cushion body 33 according to the present invention, even when the linear body 1 is installed as shown in Figure 15, the overall density of the base material 12 is uniform, and no lifting force is applied to the linear body 1. Therefore, there is no discomfort when contacted, and for the reasons mentioned above, the detection performance is also improved, making it particularly preferable. Furthermore, since the base material 12 contains voids, and these voids contribute to thermal insulation, it is even more preferable that the linear body 1 is positioned on the user's fingertip side relative to the entire base material 12. In addition, while a long noise correlation distance 68 is preferable, a low relative permittivity is also preferable. The relative permittivity depends on the amount of voids and the material, and the lower the relative permittivity, the better the noise can be removed.The substrate 12 of the present invention is particularly preferable because the amount of voids can be designed by appropriately adjusting the foaming rate, which reduces the relative permittivity and leads to a reduction in the amount of noise that interferes with detection.

[0031] Furthermore, the present invention is not limited to the above embodiments. First, as for the configuration of the linear body 1, for example, unlike the above embodiments, the insulating layer 9 may not be applied, and as shown in Figures 9 and 10, the outermost layer of the linear body 1 may be the outer layer 5d of the conductor strands. When such a linear body 1 is used, the foam constituting the base material penetrates between the strands of the conductor strands, firmly fixing the conductor strands, i.e., the linear body 1, and preventing the wiring pattern from shifting, which is preferable. However, by applying the insulating layer 9, leakage from the conductor can be strictly prevented, and noise to other sensor units, for example, can be prevented, so it is preferable to design according to the purpose of the product.

[0032] Furthermore, the linear body 1 may be used for purposes other than as a heater wire, a heater / sensor combined wire, or a guard wire. If the linear body 1 is used as a heater wire, the cushion bodies 31 and 33 become a heater unit, and if it is used as a sensor wire, the cushion bodies 31 and 33 become a sensor unit. By using both of the two linear bodies 1 as heater wires, the heating performance is particularly improved. As a sensor wire, it can be used as a capacitance sensor or other sensors such as temperature sensors. As a type of temperature sensor, the linear body can be made into a solder wire and used as an abnormal temperature detection unit. In the sense of detecting radio waves, it is also conceivable to use the linear body as an antenna wire and use it as an antenna unit. It is also conceivable to use a linear body that contains both a conductor that performs a heater function and a conductor that performs a sensor function, or to use the linear body 1 as a shield / guard wire. Furthermore, in Embodiment 2, the wiring patterns of the linear body 1 on the two temporary fixing members 32 are the same shape, and the linear body 1 is wired in a mirror image as shown in Figure 15, but the wiring pattern of the linear body 1 is not limited to this. By rotating one of the temporary fixing members 32 by 90 degrees, the wiring patterns may intersect, or they may be fixed so that the wiring patterns do not overlap. Considering the cushioning properties of the cushion bodies 31 and 33, it is preferable that the wiring patterns of the linear body 1 do not overlap, but considering the effect as a guard line, it is preferable that the wiring patterns overlap when viewed from the surface direction.

[0033] Furthermore, it is conceivable that the conductor strands 5a may not have an insulating coating 5b formed on them. For example, a configuration in which no insulating coating 5b is formed on any of the conductor strands 5a, a configuration in which conductor strands 5a covered with the insulating coating 5b and conductor strands 5a not covered with the insulating coating 5b are arranged alternately, and a configuration in which only some of the conductor strands 5a are covered with the insulating coating 5b or not covered at all are conceivable, and various other configurations are also possible. In addition, it is also conceivable that the core wire 3 and the conductor strands 5a are twisted together.

[0034] Examples of the core wire 3 include monofilaments, multifilaments, spuns, or other fiber materials of inorganic fibers such as glass fibers, or organic fibers such as polyethylene terephthalate, aliphatic polyamide fibers, aromatic polyamide fibers, and fully aromatic polyester fibers, or fibers having a core material made of such organic polymer materials, with a thermoplastic organic polymer material covering its circumference. Furthermore, when a core wire 3 with heat shrinkability and heat meltability is used, if the conductor strands 5a break and overheat abnormally, the core wire 3 melts, breaks, and shrinks. When the core wire 3 shrinks, the conductor strands 5a wound around the core wire 3 follow the movement of the core wire 3, causing the ends of the broken conductor strands 5a to separate. As a result, the ends of the broken conductor strands 5a no longer repeatedly touch and separate. Also, the ends of the broken conductor strands 5a no longer make contact with each other with only a small contact area, such as point contact. This prevents abnormal heat generation. Furthermore, if the conductor strands 5a are insulated by the insulating coating 5b, the core wire 3 does not need to be made of an insulating material. For example, stainless steel wire or titanium alloy wire can be used as the core wire 3. However, since there is a possibility of the conductor strands 5a breaking, it is better for the core wire 3 to be made of an insulating material.

[0035] Conventional known materials can be used as the conductor strand 5a, such as copper wire, copper alloy wire, nickel wire, iron wire, aluminum wire, nickel-chromium alloy wire, iron-chromium alloy wire, etc. Examples of copper alloy wires include tin-copper alloy wire, copper-nickel alloy wire, and silver-containing copper alloy wire in which a copper solid solution and a copper-silver eutectic form fibers. Of these, copper wire or copper alloy wire is preferred from the viewpoint of balancing cost and properties. These copper wires or copper alloy wires come in soft and hard types, but from the viewpoint of bending resistance, the hard type is particularly preferred over the soft type. Hard copper wire and hard copper alloy wire are those in which individual metal crystal grains are stretched long in the processing direction by cold working such as wire drawing, resulting in a fibrous structure. When such hard copper wire or hard copper alloy wire is heated above the recrystallization temperature, the processing strain generated in the metal crystal is eliminated, and crystal nuclei that will serve as the starting points for new metal crystals begin to appear. These crystal nuclei develop and undergo recrystallization, sequentially replacing old crystal grains, resulting in further grain growth. Soft copper wire and soft copper alloy wire are in this state of crystal grain growth. Compared to hard copper wire and hard copper alloy wire, soft copper wire and soft copper alloy wire have higher elongation and electrical resistance, but lower tensile strength, resulting in lower bending resistance. Thus, since hard copper wire and hard copper alloy wire become soft copper wire or soft copper alloy wire with low bending resistance through heat treatment, it is preferable to perform processing with as little thermal history as possible. Furthermore, hard copper wire is defined in JIS-C3101 (1994) and soft copper wire in JIS-C3102 (1984). Soft copper wire is defined as having an elongation of 15% or more for outer diameters of 0.10 to 0.26 mm, 20% or more for outer diameters of 0.29 to 0.70 mm, 25% or more for outer diameters of 0.80 to 1.8 mm, and 30% or more for outer diameters of 2.0 to 7.0 mm. Copper wire also includes wires that are tin-plated. Tin-plated hard copper wire is defined in JIS-C3151 (1994) and tin-plated soft copper wire is defined in JIS-C3152 (1984). In addition, various cross-sectional shapes can be used for the conductor strands 5a, and are not limited to the commonly used circular cross-section; so-called flat rectangular wires may also be used.

[0036] When a temperature-sensing sensor wire is used as the linear body 1, the conductor strand 5a is preferably made of a material that exhibits a large change in resistance due to temperature changes. Examples include various metal wires such as copper wire, copper alloy wire, nickel wire, iron wire, aluminum wire, nickel-chromium alloy wire, copper-nickel alloy, and iron-chromium alloy, as well as carbon fiber wire and conductive resin wire. Among these, those with a positive characteristic temperature coefficient are preferred. Nickel wire and platinum wire, in particular, which have large coefficients, are preferably used. With a positive characteristic temperature coefficient, the resistance value increases as the temperature rises, and when the resistance value increases, it is judged as an abnormal temperature, and the control method stops the power supply. Therefore, if the conductor strand 5a breaks, the resistance value becomes infinite, and the power supply will be stopped as if an abnormal temperature had occurred. This is a highly reliable method when viewed as a safety device.

[0037] When winding conductor strands 5a onto a core wire 3, among the materials for conductor strands 5a described above, those with a small amount of springback when wound are preferred. For example, silver-containing copper alloy wire, in which copper solid solution and copper-silver eutectic form fibers, has excellent tensile strength and flexibility, but it is prone to springback when wound. Therefore, when winding onto the core wire 3, the conductor strands 5a are prone to lifting or breaking due to excessive winding tension, and are also prone to twisting after processing, which is undesirable. In particular, if the conductor strands 5a are covered with an insulating coating 5b, the restoring force of this insulating coating 5b will also be added. Therefore, it is important to select a conductor strand 5a with a small recovery rate to compensate for the restoring force of the insulating coating 5b.

[0038] The insulating coating 5b covering the conductor strand 5a may be formed by two layers, an inner layer 5c and an outer layer 5d, as in the above embodiment, or by three or more layers, or by a single layer. When there are multiple layers, it is preferable that the thermal decomposition temperature of the material constituting the inner layer is lower than the lower of the melting point or thermal decomposition temperature of the material constituting the outer layer. Here, the inner layer is the layer formed on the conductor strand 5a. The outer layer is simply the layer outside of this inner layer, so it is also possible to form another outer layer further outside the outer layer, or to form another intermediate layer between the inner layer and the outer layer.

[0039] The insulating coating 5b can be made from various materials, such as polyurethane resin, polyamide resin, polyimide resin, polyamide-imide resin, polyester-imide resin, nylon resin, polyester-nylon resin, polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, polybenzimidazole resin, vinyl chloride resin, fluororesin, and silicone resin. Multiple types of these materials may be used in combination, and various known additives such as flame retardants and anti-aging agents may be added. Materials are combined from these resins to ensure that the thermal decomposition temperature of the material constituting the inner layer 5c is lower than the lower of the melting point or thermal decomposition temperature of the material constituting the outer layer 5d. The material for the inner layer 5c can be selected from polyurethane resin, vinyl chloride resin, polyacetal resin, polystyrene resin, polypropylene resin, polymethyl methacrylate, polyester resins such as polyethylene terephthalate, polyvinyl alcohol, etc. In particular, it is preferable that the material for the inner layer 5c is a thermosetting resin, and the material constituting the outer layer 5d is a thermosetting resin. Here, the thermosetting resin also includes crosslinkable materials. From the viewpoint of heating characteristics as a heater wire and ease of terminal processing such as soldering, it is preferable that the material of the inner layer 5c is polyurethane resin or polyester resin, and the material of the outer layer 5d is any of polyimide resin, polyamide-imide resin, or silicone resin. In particular, it is preferable that the material of the inner layer 5c is polyurethane resin and the material of the outer layer 5d is polyamide-imide resin. This polyurethane resin may be, for example, an imide-containing polyurethane, or any other type that has undergone various modifications or formulations.

[0040] Furthermore, the thickness of the insulating coating 5b is preferably 3 to 30% of the diameter of the conductor strand 5a. If it is less than 3%, sufficient voltage resistance characteristics cannot be obtained, and there is a possibility that the purpose of individually coating the conductor strand 5a will be lost. If it exceeds 30%, it becomes difficult to remove the insulating coating 5b when crimping the connection terminals, and the heater wire becomes unnecessarily thick.

[0041] When winding the above-mentioned conductor strands 5a onto the core wire 3 by aligning or twisting them together, aligning them is preferable to twisting them together. This is because the diameter of the heater wire becomes smaller and the surface becomes smoother. In addition to aligning or twisting, it is also possible to braid the conductor strands 5a onto the core wire 3.

[0042] One possible linear body 1 according to the present invention is one in which an insulating layer 9 is formed. This insulating layer 9 prevents current from flowing to other components even if the conductor wire 5a breaks, and also insulates against high-temperature heat generation in the event of a spark. The insulating layer 9 can be formed by extrusion molding or by covering it with an insulating layer 9 that has been pre-formed into a tube shape; there are no particular limitations on the method of formation. Forming the insulating layer 9 by extrusion molding is preferable because it fixes the position of the conductor wire 5a, thereby preventing friction and bending of the conductor wire 5a due to displacement, and thus improving bending resistance. The material constituting the insulating layer 9 can be appropriately designed depending on the usage form and environment of the linear body 1. Examples include polyolefin resins, polyester resins, polyurethane resins, aromatic polyamide resins, aliphatic polyamide resins, vinyl chloride resins, modified noryl resins (polyphenylene oxide resins), nylon resins, polystyrene resins, fluororesins, synthetic rubbers, fluororubber, ethylene-based thermoplastic elastomers, urethane-based thermoplastic elastomers, styrene-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and many others. In particular, a polymer composition having flame retardancy is preferably used. A polymer composition having flame retardancy here refers to one with an oxygen index of 21 or higher in the JIS-K7201 (1999) flammability test. Those with an oxygen index of 26 or higher are particularly preferred. To obtain such flame retardancy, flame retardants may be appropriately blended into the material constituting the insulating layer 9 described above. Examples of flame retardants include metal hydrates such as magnesium hydroxide and aluminum hydroxide, antimony oxide, melamine compounds, phosphorus compounds, chlorine-based flame retardants, and bromine-based flame retardants. These flame retardants may be appropriately surface-treated using known methods.

[0043] On the outer periphery of the conductor strand 5a, not only the layer of the insulator layer 9 but also other layers may be appropriately formed. Further, the insulator layer 9 is not limited to being formed continuously in the length direction. For example, it can be formed in a linear shape, a spiral shape, a dot pattern, or intermittently along the length direction of the linear body 1. However, from the viewpoint of adhesion strength, it is preferable that the insulator layer 9 is formed continuously in the length direction.

[0044] In addition, the linear body 1 obtained as described above preferably has a bending number of 20,000 or more until at least one of the conductor strands breaks in a bending test in which it is bent by 90 degrees with a curvature radius of 6 times its self-diameter.

[0045] The foams constituting the base materials 11 and 12 are not limited to the two-component mixed foamed polyurethane resin. For example, various polymer foams such as foamed resin sheets and foamed rubber sheets made of other materials are conceivable. In particular, those having voids and excellent stretchability are preferable, and those with adjusted hardness so that the unevenness of the heater wire does not appear on the surface are preferable. Further, to adjust the hardness, there are methods such as adjusting the foaming ratio, making the state of the bubbles into closed cells or open cells, and using a material with the appropriate hardness according to the purpose. As the material, it may be selected from various resins, rubbers, thermoplastic elastomers, etc., such as polyurethane resin, chloroprene rubber, silicone resin, silicone rubber, neoprene rubber, diene-based rubber, nitrile rubber, natural rubber, polyethylene resin, polypropylene resin, vinyl chloride resin, ethylene-vinyl acetate copolymer. As the base materials 11 and 12, flame-retardant ones are preferable, and those appropriately mixed with flame-retardant fibers or flame retardants are preferably used. Also, a plurality of base materials 11 and 12 can be used by laminating them, etc. In this case, materials with different materials or different porosity, etc. can be used for each of the base materials 11 and 12. In the case of the foamed polyurethane resin, it is conceivable to mix the isocyanate liquid and the polyol liquid immediately before injecting them into the mold.

[0046] For the mold frame 61 and lid frame 62, known metal molds can be used, but they do not have to be made of metal. However, since it is necessary to preheat the mold to 60°C when foaming urethane by two-component mixing, it is preferable that the mold can withstand the preheating temperature. Furthermore, it is preferable to construct a shield with an outer shape of the same size as or slightly larger than the cushion body shape to be created inside the mold using clay or the like, as this reduces the number of steps required, such as cutting the base material after foaming the base material 11 and 12, and also reduces material consumption. In addition, the shape of the mold frame 61 and lid frame 62 is not limited to a cubic system as shown in Figure 1. For example, by using a cylindrical mold frame 61, the cushion body 31 and 33 can be foamed into a cylindrical shape, improving the processability of the winding work. In addition, the shape of the mold frame 61 and lid frame 62 can be appropriately selected, such as a structure in which the mold frame 61 and lid frame 62 are inclined so that the ends of the base material 11 and 12 become tapered, and the cushion body 31 and 33 can be foamed into a predetermined shape.

[0047] In addition, the adhesive layer 20 constituting the cushion bodies 31 and 33 may be an elastic stretch layer 20. The purpose of the stretch layer 20 is to be a member for fixing the wiring pattern of the linear body 1, and whether or not it is adhesive can be considered an appropriate design consideration. Furthermore, the form of the stretch layer 20 is not limited to a film or sheet, and it may be a nonwoven fabric. The elasticity of the stretch layer 20 can be provided by methods such as creating holes in advance by punching, thinning the thickness, reducing the basis weight, or using a nonwoven fabric made by a chemical bonding method, or other known methods may be used. As an example of the stretch layer 20, it may be a web made of filaments (long fibers) by melt-extruding and spinning the fiber constituent material. If the stretch layer 20 is a nonwoven fabric, the basis weight may be 20 to 40 g / m ２When it is like this, it is preferable because it has appropriate elasticity and strength. When the stretch layer 20 is made of a material other than a non-woven fabric, it is preferably a material that allows the characters on the back surface to be seen through visually as a standard. Further, the stretch layer 20 has a first direction and a second direction orthogonal to the first direction in a direction horizontal to the main surface. Here, it is preferable that the stretch layer 20 has a maximum elasticity of 150% in the first direction and a maximum elasticity of 105% in the second direction. The elasticity is measured for the stretch layer 20 alone without fixing the linear body 1, and refers to the numerical value until the stretch layer 20 is completely broken. By having the above-described elasticity, it is possible to appropriately stretch while fixing the wiring pattern of the linear body 1, which is particularly preferable. The cushion bodies 31 and 33 are provided with such a stretch layer 20, so that the stretchability is improved and the assemblability with respect to the steering wheel core material 77 and the like is good, so that the quality and productivity can be improved.

[0048] Furthermore, the cushion bodies 31 and 33 manufactured by the above-described method can wire the linear body 1 up to the vicinity of the end portion of the base materials 11 and 12. The vicinity of the end portion of the base material refers to the distance from the outermost end of the base material to five times the wire diameter of the linear body. For example, in the manufacturing methods of the units according to Patent Documents 1 to 7, after wiring the linear body on the base material, the outer shape of the base material was processed with a blade such as a Thomson blade. Therefore, from the viewpoint of fear of disconnection, wiring the linear body to the end portion of the base material was hesitant. However, in the method according to the present invention, there is no fear of disconnection by the blade, and the linear body can be wired up to the vicinity of the end portion of the base material. With this structure, when the cushion body is assembled to a steering wheel, a seat, an interior of a vehicle interior, etc., the linear body can be arranged up to the ends thereof, so that the temperature rising performance and the detection performance are particularly excellent. Also, when the cushion body is wound and assembled, the linear body can be arranged at the butting portion of the cushion body, so that the temperature rising performance and the detection performance are particularly excellent.

[0049] The cushion bodies 31 and 33 according to the present invention can be stacked on top of other cushion bodies 31 and 33. For example, cushion bodies 31 and 33 can be created using two linear bodies 1 as a heater wire / sensor wire and a guard wire, and then cushion bodies 31 and 33 with heater wires wired on both sides can be stacked on top of these cushion bodies 31 and 33. This can provide excellent heating performance as well as excellent detection performance.

[0050] The cushions 31 and 33 according to the present invention can be used in various applications other than the steering wheel shown in Figure 11. For example, the cushions 31 and 33 having the above configuration can be embedded and installed in the interior of a vehicle. One example is their installation in interior components such as A-pillars, armrests, and door trims.

[0051] As detailed above, the present invention makes it possible to prevent users from feeling any discomfort when operating the steering wheel. Such cushions 31 and 33 can be used, for example, in steering wheels, seats, and interiors of automobiles, ships, various transport vehicles, various agricultural vehicles, and various heavy construction machinery. They can be suitably used as heater units for warming the steering wheel or seat, as temperature sensor units for detecting the temperature of the steering wheel or seat, or as capacitance sensor units for detecting the steering wheel's temperature or the seat's seating position. Furthermore, taking advantage of the fact that the cushions 31 and 33 according to the present invention are flat with no irregularities in the linear portion, they can be used not only in steering wheels and seats but also in other applications. For example, they can be applied to electric blankets, electric carpets, heated toilet seats, heaters for anti-fog mirrors, cooking appliances, floor heating heaters, clothing heaters, various planar temperature detectors, capacitance detectors, etc.

[0052] 1 Linear body 3 Core material 5a Conductor strand 5b Insulating coating 5c ​​Inner layer 5d Outer layer 9 Insulating layer 11 Base material 12 Base material 18 Temporary release film 19 Release film for application 20 Adhesive layer 22 Adhesive layer 31 Cushion body 32 Temporary fixing member 33 Cushion body 41 Adhesive section 42 Skin section 61 Mold 62 Lid frame 63 Inlet 64 Nearby part of linear body 65 Remote part of linear body 67 Sensing correlation distance 68 Noise correlation distance 71 Steering wheel 77 Wheel core material 78 Covering material

Claims

1. A cushion body comprising a base material made of foam, an adhesive layer provided on the outermost surface of the base material, and a linear body partially embedded in the base material, wherein the linear body is in contact with the adhesive layer.

2. The cushion body according to claim 1, wherein the adhesive layer has a generally flat shape.

3. The cushion body according to claim 1, wherein the apparent density of the portion near the linear body and the portion far from the linear body are substantially the same.

4. The cushion body according to claim 1, wherein the outermost surface opposite to the surface on which the adhesive layer is provided is a skin layer.

5. The cushion body according to any one of claims 1 to 4, wherein the linear body has multiple strands that are wound or twisted together, and the foam is inserted between the multiple strands.

6. The cushion body according to any one of claims 1 to 4, wherein the linear body is a heater wire or a sensor wire.

7. The cushion body according to any one of claims 1 to 4, wherein the area where the adhesive layer is provided is defined as an adhesive section, and in the adhesive section, the linear body is in contact with the adhesive layer, and the adhesive section is provided on two or more surfaces.

8. The cushion body according to claim 7, wherein the outermost surface of the substrate other than the adhesive area is a skin area.

9. A method for manufacturing a cushion body, comprising the steps of: placing an adhesive layer and a linear body in a mold; and forming a substrate integrally with the adhesive layer and the linear body in the mold.

Images