Heater and sensor complex for use in a vehicle

Abstract

To provide a heater and sensor combination that is easy to arrange and has a high sensor sensitivity. [Solution] A heater and sensor composite for use in a mobile body comprises a sheet-like sensor element containing carbon nanotubes and having an uneven surface, which detects the approach of an occupant of the mobile body, and a sheet-like heater element containing carbon nanotubes and laminated on the uneven surface, which generates heat when electricity is passed through it.

Description

[Technical Field]

[0001] The present disclosure relates to a heater and sensor combination for use in a vehicle. [Background technology]

[0002] Various touch sensors have been proposed for use on vehicle steering wheels. For example, Patent Document 1 discloses a technology that uses a sheet-like sensor wrapped around the steering wheel to detect whether an occupant is gripping the steering wheel. The use of carbon nanotubes (CNTs) as the elements of such sensors has been considered. CNTs have the property that their resistance value changes when their shape changes. Utilizing this property, CNTs can be used as sensor elements for detecting whether the steering wheel is being gripped. Furthermore, because CNTs generate heat when electricity is applied, they can also be used as heater elements in grip heaters. For this reason, attempts have been made to use CNTs as sensor elements and heater elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-178527 Summary of the Invention [Problem to be solved by the invention]

[0004] However, CNTs are relatively hard, making it difficult to wrap them around a steering wheel. Furthermore, the amount of deformation caused by the CNTs when gripped by a passenger is small, making it difficult to increase the sensitivity of the sensor. This problem is not limited to vehicles, but is common to any moving object. Furthermore, this problem is not limited to steering wheels, but is common to any type of structure in a moving object when a heater and sensor complex is arranged along the surface of such a structure. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a composite of a heater and a sensor for use in a vehicle, the composite including: a sheet-like sensor element containing carbon nanotubes and having an uneven surface, the sensor element detecting the approach of an occupant of the vehicle; and a sheet-like heater element containing carbon nanotubes and laminated on the uneven surface, the heater element generating heat when current is applied. In this composite, the sensor element has an uneven surface, which makes it easier to place the composite on the surface of a structure compared to a configuration in which the sensor element does not have an uneven surface. Furthermore, the sensor element changes shape more significantly when the composite is touched, which increases the sensitivity of the sensor. (2) In the composite of the above embodiment, the heater element may have a smooth surface on the side opposite to the surface facing the uneven surface. According to the composite of this form, the heater element has a smooth surface, and by orienting the smooth surface toward the design surface, it is possible to prevent the design of the structure in which the composite is used from being impaired. (3) In the composite of the above aspect, the resistance value of the sensor element may be smaller than the resistance value of the heater element. According to this type of composite, the resistance value of the sensor element is smaller than the resistance value of the heater element, so that the heat generation amount of the heater can be increased while improving the sensitivity of the sensor. (4) The composite of the above embodiment may further include a spacer sandwiched between the sensor element and the heater element. Since the composite of this type further includes a spacer, the concave and convex shape of the sensor element can be maintained even when force is repeatedly applied to the composite, as compared to a configuration without a spacer.

[0007] The present disclosure may be realized in various forms, such as a steering system including a composite body, a mobile body having a composite body mounted thereon, and the like. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of a steering wheel on which a composite according to one embodiment of the present disclosure is mounted. [Figure 2] FIG. 2 is an enlarged cross-sectional view schematically showing a cross section of a composite in the thickness direction. [Figure 3] FIG. 10 is a cross-sectional view of a composite body according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: 1 is a front view of a steering wheel SR on which a composite 100 according to one embodiment of the present disclosure is mounted. The steering wheel SR is mounted on a vehicle and configured as a part of a steering device for changing the direction of travel of the vehicle. The steering wheel SR includes a hub portion 10, a rim portion 20, and spoke portions 30.

[0010] <Configuration of Steering SR> The hub portion 10 is located at the center of the steering wheel SR when viewed from the front. The hub portion 10 is connected to the rotation shaft of a steering column in the steering device.

[0011] The rim portion 20 is located around the hub portion 10 and has an annular outer shape. The rim portion 20 is gripped by the occupant to steer the vehicle. The rim portion 20 includes a core metal, a cushion layer, a composite 100 (described later), and a skin layer. The core metal is the skeleton of the rim portion 20 made of metal. The cushion layer is made of an elastic material such as urethane and covers the core metal. The composite 100 covers the cushion layer. Details of the composite 100 will be described later. The skin layer is made of natural leather, synthetic leather, or the like. The skin layer forms the outer surface of the rim portion 20 and comes into contact with the occupant's hands when gripping the steering wheel SR.

[0012] The spokes 30 connect the hub 10 and the rim 20. In this embodiment, three spokes 30 are provided. The spokes 30 may be provided with a functional member such as a switch.

[0013] <Configuration of Complex 100> FIG. 2 is an enlarged cross-sectional view schematically illustrating a cross section of the composite 100 in the thickness direction. The composite 100 is used as a sensor and a heater. In this embodiment, the composite 100 is used as a touch sensor for detecting gripping of the steering wheel SR and a grip heater for heating the steering wheel SR. The composite 100 has a sheet-like appearance and is wrapped around the cushion layer of the rim portion 20. The composite 100 includes a sensor element 200 and a heater element 300.

[0014] The sensor element 200 has a sheet-like external shape. The sensor element 200 contains carbon nanotubes (hereinafter also referred to as CNTs). The sensor element 200 is manufactured by impregnating a substrate such as a nonwoven fabric with a CNT dispersion liquid. Alternatively, the sensor element 200 may be manufactured by printing ink-like CNTs on a thin film such as a film. The sensor element 200 has an uneven surface SF1 on the side on which the heater element 300 (described later) is laminated. The height of the unevenness of the uneven surface SF1 is, for example, 10 μm to 40 μm. When the sensor element 200 is manufactured by impregnating a substrate such as a nonwoven fabric with a CNT dispersion liquid, the unevenness can be provided by processing the surface of the substrate. When the sensor element 200 is manufactured by printing ink-like CNTs, the unevenness can be provided by varying the thickness of the printed CNTs.

[0015] The sensor element 200 is used as a touch sensor and detects the proximity of an occupant to the steering wheel SR. In this disclosure, "proximity" has a broad meaning that includes a state in which the occupant grips the steering wheel SR and a state in which the occupant is very close to the steering wheel SR. The sensor element 200 in this embodiment functions as a pressure sensor. Specifically, when the sensor element 200 changes shape due to being gripped by the occupant, the resistance value of the sensor element 200 changes. An ECU mounted on the vehicle detects the occupant's grip by interpreting this change in resistance value as a change in voltage.

[0016] The heater element 300 has a sheet-like external shape. The heater element 300 includes CNTs. The heater element 300 can be manufactured by impregnating a substrate such as a nonwoven fabric with a CNT dispersion liquid. Alternatively, the heater element 300 can be manufactured by printing ink-like CNTs onto a thin film such as a film. The heater element 300 is laminated on the textured surface SF1 of the sensor element 200. The heater element 300 and the sensor element 200 may be bonded to each other, for example, with an adhesive.

[0017] In this embodiment, the heater element 300 has a smooth surface SF2 on the side opposite to the uneven surface SF1. In this disclosure, the term "smooth surface" means that even if the surface has unevenness, the height of the unevenness is less than 10 μm.

[0018] The heater element 300 is used as a grip heater, and generates heat when energized to warm the hands of the occupant gripping the steering wheel SR. When the heater element 300 contains CNT, it is possible to warm the occupant's hands while suppressing uneven heating with less power than when a metal material is used as the heater element 300.

[0019] In this embodiment, the resistance value of the sensor element 200 is smaller than the resistance value of the heater element 300. Note that this resistance value is a value measured in a state where the composite 100 is not held by an occupant. The resistance value is adjusted by the amount of CNT contained in the sensor element 200 and the heater element 300.

[0020] According to the composite 100 of the first embodiment described above, the sensor element 200 has the uneven surface SF1, so the composite 100 can be easily wrapped around the steering wheel SR compared to a configuration in which the sensor element 200 does not have the uneven surface SF1. This is because the uneven shape of the uneven surface SF1 makes it easier for the shape of the sensor element 200 to change.

[0021] Furthermore, according to the composite 100 of the first embodiment, the sensor element 200 has the uneven surface SF1, and therefore, the amount of change in the shape of the sensor element 200 when the composite 100 is touched can be made larger compared to a configuration in which the sensor element 200 does not have the uneven surface SF1. This increases the amount of change in the resistance value of the sensor element 200 when the composite 100 is gripped by an occupant, thereby improving the sensitivity of the sensor.

[0022] Furthermore, according to the composite 100 of the first embodiment, the heater element 300 has a smooth surface SF2 on the side opposite to the uneven surface SF1 of the sensor element 200. By orienting this smooth surface SF2 as the design surface, it is possible to prevent a deterioration in the design. For example, when the composite 100 is provided on a steering wheel SR, the composite 100 is covered with a skin layer. In this case, if the surface of the heater element 300 is uneven, unevenness will also occur in the skin layer, thereby reducing the design. In contrast, by having the smooth surface SF2 of the heater element 300 as in this embodiment, it is possible to prevent unevenness from occurring in the skin layer, thereby preventing a deterioration in the design.

[0023] Furthermore, according to the composite 100 of the first embodiment, the resistance value of the sensor element 200 is smaller than the resistance value of the heater element 300, and therefore, compared to a configuration that does not have such a resistance relationship, it is possible to increase the heat generation amount of the heater while improving the sensitivity of the sensor.

[0024] B. Second embodiment: 3 is a cross-sectional view of a composite 100b according to the second embodiment. The composite 100b according to the second embodiment differs from the composite 100 according to the first embodiment in that it further includes a spacer 400. Configurations not described below are similar to those of the composite 100 according to the first embodiment.

[0025] The spacer 400 is disposed on the uneven surface SF1 of the sensor element 200 and is sandwiched between the sensor element 200 and the heater element 300. The spacer 400 is a sheet-like member made of, for example, resin. The thickness of the spacer 400 is, for example, 10 to 20 μm. The elastic modulus of the spacer 400 is preferably higher than the elastic moduli of the sensor element 200 and the heater element 300. The spacer 400 is bonded to the sensor element 200 on one side and to the heater element 300 on the other side.

[0026] According to the composite 100b of the second embodiment described above, the spacer 400 is further provided, and therefore the uneven shape of the sensor element 200 can be maintained even if force is repeatedly applied to the composite 100, compared to a configuration not including the spacer 400.

[0027] C. Other Embodiments: (C1) In each of the above embodiments, the heater element 300 has a smooth surface SF2 on the side opposite to the surface facing the uneven surface SF1, but the present disclosure is not limited to this. The heater element 300 does not have to have a smooth surface SF2. Even in this configuration, the sensor element 200 has an uneven surface SF1, so that the composite 100 can be easily wound around it and the sensitivity of the sensor element 200 can be improved.

[0028] (C2) In each of the above embodiments, the resistance value of the sensor element 200 is smaller than the resistance value of the heater element 300, but the present disclosure is not limited to this. The resistance value of the sensor element 200 may be equal to or greater than the resistance value of the heater element 300. Even in such a configuration, the sensor element 200 has the uneven surface SF1, so that the composite 100 can be easily wound around it, and the sensitivity of the sensor element 200 can be improved.

[0029] (C3) In each of the above embodiments, the steering wheel SR on which the composite 100, 100b is provided is a so-called circular steering wheel in which the external shape of the rim portion 20 is annular, but the present disclosure is not limited to this. The steering wheel SR may have any shape, such as an oval or D-shape.

[0030] (C4) In the above embodiments, the sensor element 200 is used as a pressure sensor, but the present disclosure is not limited to this. The sensor element 200 may also be used as a capacitance sensor.

[0031] (C5) In each of the above embodiments, the complexes 100 and 100b may be provided on any moving object other than a vehicle. Such moving objects include, for example, ships, airplanes, spacecraft, and so-called flying cars. Furthermore, the moving object does not necessarily have to be a moving object, but may also be an object that realizes virtual movement, such as a simulator.

[0032] (C6) In each of the above embodiments, the composite 100, 100b may be provided on any structure in a moving body. Such structures include, for example, a seat, a seat belt, and a console box. According to this configuration, the sensor element 200 has the uneven surface SF1, which makes it easier to arrange on the surface of the structure compared to a configuration in which the sensor element 200 does not have the uneven surface SF1. This makes it easier to arrange, particularly when the surface of the structure is not a smooth surface. Furthermore, the sensitivity of the sensor element 200 can be improved.

[0033] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0034] 10...hub portion, 20...rim portion, 30...spoke portion, 100, 100b...composite body, 200...sensor element, 300...heater element, 400...spacer, SF1...uneven surface, SF2...smooth surface, SR...steering

Claims

1. A heater and sensor composite for use in a moving object, comprising: a sheet-like sensor element including carbon nanotubes and having an uneven surface, the sensor element detecting the approach of an occupant of the vehicle; a sheet-like heater element including carbon nanotubes and laminated on the uneven surface, the heater element generating heat when energized; A complex comprising:

2. 2. The composite of claim 1 , The heater element has a smooth surface on the side opposite to the rough surface.

3. 3. The composite of claim 2, The composite, wherein the resistance value of the sensor element is less than the resistance value of the heater element.

4. The composite according to any one of claims 1 to 3, The composite further comprising a spacer sandwiched between the sensor element and the heater element.

Images