Sensors mounted on seat belts in moving vehicles

Abstract

To provide a seat belt sensor capable of increasing sensitivity. [Solution] A sensor mounted on the seat belt of a moving body includes carbon nanotubes and has multiple sensor elements attached to the seat belt, each of which extends in the longitudinal direction of the seat belt and is arranged in a wavy pattern along the surface of the seat belt, and is arranged parallel to each other along the short direction of the seat belt.

Description

[Technical Field]

[0001] The present disclosure relates to a sensor mounted on a seat belt of a vehicle. [Background technology]

[0002] Various sensors to be attached to the seat belts of vehicles have been proposed. For example, Patent Document 1 discloses a technology for detecting the electric potential of an occupant using a sensor attached to the seat belt. It is also known to use carbon nanotubes (CNTs) as elements for such sensors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-030869 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because CNTs are a relatively hard material, their shape changes only slightly when force is applied, making it difficult to increase the sensitivity of the sensor when used as a seatbelt sensor element, since the change in resistance due to the change in shape of the CNT is also small. [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 sensor mounted on a seat belt of a moving object, the sensor including a plurality of sensor elements provided on the seat belt, each of the plurality of sensor elements including a carbon nanotube, extending in the longitudinal direction of the seat belt, being provided in a wave-like pattern along the surface of the seat belt, and being arranged in parallel to one another in the lateral direction of the seat belt. In this type of sensor, the multiple sensor elements each extend in the longitudinal direction of the seat belt and are arranged in a wave-like pattern along the surface of the seat belt, thereby improving the sensitivity of the sensor compared to a configuration in which the sensor elements are arranged in a straight line. Specifically, when a force such as tension or twisting is applied to the sensor element, stress is concentrated at the peaks and valleys of the wave-like sensor element. This stress causes a large amount of deformation in the shape of the sensor element, thereby improving the sensitivity of the sensor. (2) In the sensor of the above form, the seat belt may have a shoulder belt portion and a lap belt portion, and the plurality of sensor elements may include a first sensor portion arranged in the shoulder belt portion and a second sensor portion arranged in the lap belt portion and insulated from the first sensor portion. According to this type of sensor, the multiple sensor elements include a first sensor unit arranged in the shoulder belt portion and a second sensor unit arranged in the lap belt portion and insulated from the first sensor unit, so that sensing in the shoulder belt portion and sensing in the lap belt portion can be performed independently of each other. (3) In the sensor of the above form, the seat belt may be a three-point seat belt having a first surface and a second surface opposite to the first surface, the first surface of the shoulder belt portion configured to contact the torso of the occupant when the seat belt is worn by the occupant of the moving body, and the second surface of the lap belt portion configured to contact the torso of the occupant when worn, and the first sensor portion may be provided on the first surface and the second sensor portion may be provided on the second surface. In this configuration, the first sensor is provided on the first surface of the shoulder belt, and the second sensor is provided on the second surface of the lap belt, so that both the first sensor and the second sensor are in contact with the occupant's torso. This allows for more accurate sensing than a configuration in which both the first sensor and the second sensor are provided on the surface that does not contact the occupant's torso. Furthermore, manufacturing costs can be reduced compared to a configuration in which sensor elements are provided on both sides of the seatbelt. (4) In the sensor of the above form, the seat belt may be a three-point seat belt having a first surface and a second surface opposite to the first surface, the first surface of the shoulder belt portion configured to contact the torso of the occupant when the seat belt is worn by the occupant of the moving body, and the second surface of the lap belt portion configured to contact the torso of the occupant when worn, the first sensor portion may be provided on the second surface, and the second sensor portion may be provided on the first surface. In this embodiment of the sensor, the first sensor is provided on the second surface of the shoulder belt, and the second sensor is provided on the first surface of the lap belt. Therefore, neither the first sensor nor the second sensor comes into contact with the occupant's torso. This reduces damage or deformation of the sensor element due to repeated contact with the occupant P, compared to a configuration in which the first sensor and the second sensor are both provided on the surface that comes into contact with the occupant's torso. Furthermore, manufacturing costs can be reduced compared to a configuration in which the sensor elements are provided on both sides of the seatbelt.

[0007] The present disclosure may be realized in various forms, such as a seat belt equipped with a sensor, a moving object equipped with a sensor, and the like. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams illustrating a schematic configuration of a sensor according to an embodiment of the present disclosure. [Figure 2] FIG. [Figure 3] FIG. 10 is a diagram illustrating a schematic configuration of a sensor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: <Overall structure> FIG. 1 is a diagram illustrating a schematic configuration of a sensor 100 according to an embodiment of the present disclosure. FIG. 1 shows an occupant P wearing a seat belt 20 as viewed from the front. Note that an electrode 122, which will be described later, is omitted from FIG. 1. The sensor 100 according to this embodiment is mounted on the seat belt 20 of a vehicle and is used to detect twisting of the seat belt 20 worn by the occupant P. In this disclosure, the term "seat belt" refers to a belt-shaped member made of fibers such as polyamide.

[0010] In this disclosure, the direction along the vehicle's traveling direction is referred to as the "front-rear direction." The vertical direction as seen by the driver in the vehicle is referred to as the "up-down direction." The "up-down direction" may also be referred to as the "height direction." The direction along the left-right direction (width direction) of the vehicle is referred to as the "left-right direction." The "front-rear direction," "up-down direction," and "left-right direction" are directions that intersect with each other.

[0011] In addition, in the drawings of this disclosure, components located on the far side of the paper surface are shown by dashed lines for the sake of explanation.

[0012] The seat belt 20 in this embodiment is used in a so-called three-point seat belt device. The seat belt 20 includes a shoulder belt portion 21 and a lap belt portion 22. When the seat belt 20 is worn by the occupant P, the shoulder belt portion 21 extends from an anchor 26 to a tongue 23. Note that the "worn state" means that the seat belt 20 is worn by the occupant P without twisting. The anchor 26 is a member for guiding the seat belt 20, which is unwound from a retractor 25, toward the occupant P. The tongue 23 is a member for being inserted into a buckle 24 provided on the left side of the seat 10 and for fastening the seat belt 20 in the worn state. A through-hole H is formed in the tongue 23. The seat belt 20 is folded back by passing through the through-hole H. When worn, the shoulder belt portion 21 covers the occupant P from one shoulder to the other abdomen. When worn, the lap belt portion 22 extends from the tongue 23 to an underplate 27. The underplate 27 is provided on the right side of the seat 10 and is a member for fastening the seat belt 20. The lap belt portion 22 covers the abdomen of the occupant P so as to cross in the left-right direction when worn.

[0013] The seat belt 20 has a first surface SF1 and a second surface SF2 opposite to the first surface SF1. The first surface SF1 of the shoulder belt portion 21 contacts the torso B of the occupant P when the seat belt 20 is worn. The second surface SF2 of the lap belt portion 22 contacts the torso B of the occupant P when the seat belt 20 is worn. Because the seat belt 20 is folded back by the tongue 23, the surfaces of the shoulder belt portion 21 and the lap belt portion 22 that contact the torso B of the occupant P are different from each other.

[0014] <Configuration of sensor 100> 2 is a front view of the seat belt 20. In FIG. 2, the second surface SF2 is located on the front side of the paper. FIG. 2 shows an enlarged schematic view of a portion of the seat belt 20 where the sensor 100 is provided. As shown in FIG. 2, the sensor 100 includes a plurality of sensor elements 110 and a plurality of electrodes 120.

[0015] The sensor element 110 includes a carbon nanotube (hereinafter also referred to as CNT). The sensor element 110 has a property that its resistance value changes due to a change in shape, such as twisting. Each of the sensor elements 110 extends in the longitudinal direction LD of the seat belt 20 and is provided in a wave shape along the surface of the seat belt 20. In this embodiment, each of the sensor elements 110 is provided in a sinusoidal wave shape. Specifically, each of the sensor elements 110 extends along the longitudinal direction LD while alternately protruding from one end side and the other end side in the lateral direction SD of the seat belt 20. Furthermore, each of the sensor elements 110 is arranged in parallel to one another along the lateral direction SD. In this embodiment, three sensor elements 110 are arranged.

[0016] In this embodiment, the sensor element 110 includes a first sensor unit 111 and a second sensor unit 112. The first sensor unit 111 is disposed in the shoulder belt unit 21. In this embodiment, the first sensor unit 111 is disposed on a first surface SF1 of the shoulder belt unit 21. The second sensor unit 112 is disposed in the lap belt unit 22. In this embodiment, the second sensor unit 112 is disposed on a second surface SF2 of the lap belt unit 22. Therefore, both the first sensor unit 111 and the second sensor unit 112 are disposed on surfaces that come into contact with the torso B of the occupant P when the occupant P is wearing the seat belt.

[0017] The sensor element 110 is manufactured, for example, by sewing thread-like CNTs into the seat belt 20. The sensor element 110 may also be manufactured by printing ink-like CNTs on the surface of the seat belt 20.

[0018] The electrodes 120, 121, 122, and 123 are provided at both ends of the sensor element 110 in the longitudinal direction LD. In this embodiment, the electrodes 120 and 121 are provided at one end and the other end of the first sensor unit 111 in the longitudinal direction LD, respectively. The electrodes 122 and 123 are provided at one end and the other end of the second sensor unit 112 in the longitudinal direction LD, respectively. The electrodes 120 to 123 are, for example, conductive threads made of a conductive material. The electrodes 120 to 123 may also be plate-shaped members made of a metal material. The electrodes 120 to 123 are provided to energize each of the multiple sensor elements 110. The electrodes 120 to 123 are electrically connected to an ECU (ECU) of the vehicle (not shown). When the shape of the sensor element 110 changes due to twisting of the seat belt 20, the resistance value of the sensor element 110 changes, causing a change in the voltage measured by the ECU. The ECU detects the twist of the seat belt 20 by detecting the change in the applied voltage.

[0019] In this embodiment, the first sensor unit 111 and the second sensor unit 112 are insulated from each other. The insulation may be achieved, for example, by providing a sufficient distance between the first sensor unit 111 and the second sensor unit 112, or by placing an insulator between the first sensor unit 111 and the second sensor unit 112.

[0020] According to the sensor 100 of the first embodiment described above, the plurality of sensor elements 110 each extend in the longitudinal direction LD of the seat belt 20 and are provided in a wavy pattern along the surface of the seat belt 20. This allows the area in which the sensor elements 110 are provided to be larger than in a configuration in which the sensor elements 110 are provided in a straight line. This improves the sensitivity of the sensor 100. Furthermore, when a force is applied to the sensor element 110, stress is concentrated on the peaks and valleys of the wavy sensor element 110. This stress increases the amount of change in the shape of the sensor element 110. This improves the sensitivity of the sensor 100.

[0021] Furthermore, according to the sensor 100 of the first embodiment, the multiple sensor elements 110 are arranged in parallel to one another along the short direction SD of the seat belt 20, and therefore the detection range of the seat belt 20 can be made wider in the short direction SD compared to a configuration in which the sensor elements 110 are not arranged in parallel in the short direction SD.

[0022] Furthermore, according to the sensor 100 of the first embodiment, the multiple sensor elements 110 include a first sensor unit 111 arranged in the shoulder belt unit 21 and a second sensor unit 112 arranged in the lap belt unit 22 and insulated from the first sensor unit 111, so that sensing can be performed independently of each other in the shoulder belt unit 21 and the lap belt unit 22. Therefore, when the sensor 100 is used to detect twisting of the seat belt 20, twisting in the shoulder belt unit 21 and twisting in the lap belt unit 22 can be detected independently of each other.

[0023] Furthermore, according to the sensor 100 of the first embodiment, the first sensor unit 111 is provided on the first surface SF1 of the shoulder belt unit 21, and the second sensor unit 112 is provided on the second surface SF2 of the lap belt unit 22, so that both the first sensor unit 111 and the second sensor unit 112 come into contact with the torso B of the occupant P. This allows for more accurate sensing compared to a configuration in which both the first sensor unit 111 and the second sensor unit 112 are provided on surfaces that do not come into contact with the torso B of the occupant P. Furthermore, compared to a configuration in which the sensor element 110 is provided on both sides of the seat belt 20, manufacturing costs can be reduced.

[0024] Furthermore, according to the sensor 100 of the first embodiment, the sensor element 110 contains CNTs, and therefore the sensitivity of the sensor 100 can be improved compared to a configuration in which the sensor element 110 does not contain CNTs.

[0025] B. Second embodiment: 3 is a diagram illustrating a schematic configuration of a sensor 100b according to the second embodiment. The sensor 100b according to the second embodiment differs from the first sensor unit 111 and the second sensor unit 112 according to the first embodiment in the surfaces on which the first sensor unit 111b and the second sensor unit 112b are provided. The other configurations are the same as those of the sensor 100 according to the first embodiment, and therefore description thereof will be omitted.

[0026] The first sensor unit 111b is provided on the second surface SF2 of the shoulder belt unit 21. The second sensor unit 112b is provided on the first surface SF1 of the lap belt unit 22. That is, the first sensor unit 111b and the second sensor unit 112b are provided on the surface of the seat belt 20 opposite to the surface that comes into contact with the torso B of the occupant P.

[0027] According to the sensor 100b of the second embodiment described above, the first sensor portion 111b and the second sensor portion 112b are both provided on the surface of the seat belt 20 opposite to the surface that contacts the torso B of the occupant P, which prevents the sensor element 110 from being damaged or deformed due to repeated contact with the occupant P. Furthermore, compared to a configuration in which the sensor element 110 is provided on both sides of the seat belt 20, manufacturing costs can be reduced.

[0028] C. Other Embodiments: (C1) In the above embodiments, the sensors 100 and 100b are used to detect twisting of the seat belt 20, but the present disclosure is not limited to this. The sensors 100 and 100b may be used to detect biological information of the occupant P, for example.

[0029] (C2) In each of the above embodiments, the sensor element 110 is provided in a sinusoidal wave shape, but the present disclosure is not limited to this. The sensor element 110 may have any wave shape, such as a rectangular wave shape, a triangular wave shape, or a sawtooth wave shape.

[0030] (C3) In the above embodiments, the sensor element 110 is provided in both the shoulder belt portion 21 and the lap belt portion 22, but the present disclosure is not limited to this. The sensor element 110 may be provided in any location on the seat belt 20.

[0031] (C4) In each of the above embodiments, the seat belt 20 may be any type of seat belt other than a three-point seat belt.

[0032] (C5) In each of the above embodiments, the sensor 100, 100b may be provided on the seat belt 20 of any moving body other than a vehicle. Such moving bodies include, for example, ships, airplanes, spacecraft, so-called flying cars, etc. Furthermore, the moving body does not necessarily have to be a moving body, but may also be an object that realizes virtual movement, such as a simulator.

[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...seat, 20...seat belt, 21...shoulder belt portion, 22...lap belt portion, 23...tongue, 24...buckle, 25...retractor, 26...anchor, 27...underplate, 100, 100b...sensor, 110...sensor element, 111, 111b...first sensor portion, 112, 112b...second sensor portion, 120, 121, 122, 123...electrodes, B...torso, H...through hole, LD...longitudinal direction, P...occupant, SD...transverse direction, SF1...first surface, SF2...second surface

Claims

1. A sensor mounted on a seat belt of a moving object, a plurality of sensor elements including carbon nanotubes and provided on the seat belt; The plurality of sensor elements extend in the longitudinal direction of the seat belt, are provided in a wave-like pattern along the surface of the seat belt, and are arranged in parallel to one another along the lateral direction of the seat belt. Sensor.

2. 2. The sensor of claim 1, The seat belt has a shoulder belt portion and a lap belt portion, The plurality of sensor elements include a first sensor unit disposed on the shoulder belt portion and a second sensor unit disposed on the lap belt portion and insulated from the first sensor unit. Sensor.

3. 3. The sensor of claim 2, The seat belt is a three-point seat belt and has a first surface and a second surface opposite to the first surface, the first surface of the shoulder belt portion is configured to come into contact with a trunk of an occupant in a wearing state in which the seat belt is worn by the occupant of the moving body, the second surface of the lap belt portion is configured to contact a torso of the occupant in the worn state, the first sensor unit is provided on the first surface, The second sensor unit is provided on the second surface. Sensor.

4. 3. The sensor of claim 2, The seat belt is a three-point seat belt and has a first surface and a second surface opposite to the first surface, the first surface of the shoulder belt portion is configured to come into contact with a trunk of an occupant in a wearing state in which the seat belt is worn by the occupant of the moving body, the second surface of the lap belt portion is configured to contact a torso of the occupant in the worn state, the first sensor unit is provided on the second surface, The second sensor unit is provided on the first surface. Sensor.

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