Steering device

Abstract

To provide a steering device technology capable of ensuring flexibility, and detecting a gripping situation while being affected by deterioration of a coating film.SOLUTION: A steering device includes a rotary part and a grip part that is connected to the rotary part and gripped by an occupant. The grip part includes a core metal part and a cover part, which covers the core metal part, and includes a first layer, second layer, and third layer. The first layer is located near the core metal part relative to the second layer and third layer, and exhibits conductivity. The second layer is interposed between the first layer and third layer, and made of a material which does not exhibit conductivity but exhibits flexibility. The third layer is exposed to outside in the grip part and made of a material that does not exhibit conductivity. The steering device further includes a detector that detects a change in electrostatic capacity between an occupant who grips the grip part and the first layer, and a control unit that determines a gripping situation of the grip part on the basis of the change in electrostatic capacity detected by the detector.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a steering device. [Background technology]

[0002] In the steering wheel of Patent Document 1, the skin material covering the core metal covering portion contains a conductive material. The core metal covering portion covers the core metal. The skin material includes a base layer attached to the core metal covering portion, an elastic layer laminated on the base layer, and a coating layer painted on the elastic layer. The elastic layer is made of flexible elastomer material, rubber material, polyvinyl chloride, etc. The coating layer is formed by applying paint containing urethane resin, acrylic resin, silicone resin, fluororesin, etc. The elastic layer and the coating layer contain a conductive material. In Patent Document 1, the elastic layer and the core metal are used as electrodes, and the driver's gripping state of the steering wheel is detected based on a change in capacitance of a capacitance sensor that detects the capacitance between them. In the steering wheel of Patent Document 1, the flexibility of the skin material is ensured by the elastic layer. In addition, in the steering wheel of Patent Document 1, the conductive material is contained in the coating layer, and the conductive material is present in a position close to the driver's hand, so that the gripping state can be detected together with the elastic layer containing the conductive material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-992 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, it is considered that the elastic layer contains a conductive material by plating the elastic layer. It is generally known that plating the elastic layer reduces the flexibility of the elastic layer compared to a non-plated form. In addition, it is generally known that the coating of the steering wheel is easily deteriorated because it is exposed to air. Therefore, a steering device that can detect the gripping state while ensuring flexibility and not being affected by deterioration of the coating is desired. [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 steering device, the steering device being provided on a moving body and including a rotating part rotatably attached to the moving body and a grip part connected to the rotating part and gripped by an occupant, the grip part including a core part sandwiching the rotating part and a covering part covering the core part, the covering part including a first layer, a second layer, and a third layer, the first layer being disposed closer to the core part than the second layer and the third layer and having electrical conductivity, the second layer being disposed between the first layer and the third layer and being made of a material that is not electrically conductive and is flexible, the third layer being exposed to the outside at the grip part and being made of a material that is not electrically conductive, the steering device further including a detector that detects a change in capacitance between the occupant gripping the grip part and the first layer, and a control unit that determines a gripping state of the grip part based on the change in capacitance detected by the detector. According to the steering device of this embodiment, since the first layer is conductive, the gripping state of the gripping portion is detected based on a change in the capacitance of the first layer. Compared to an embodiment in which a conductive material is included in the second layer made of a flexible material or in the third layer which is in contact with the occupant and therefore prone to exposure to air, the flexibility of the covering portion is ensured and the gripping state can be detected without being affected by deterioration of the third layer. (2) In the steering device of the above-described form, the first layer may be adhered to the core bar portion by double-sided tape or an adhesive, and the second layer may be laminated to the first layer by double-sided tape or an adhesive. When the first layer having a conductive material comes into contact with air, the low dielectric constant of air may reduce the accuracy of the first layer as a detection electrode. According to the steering device of this embodiment, the first layer is adhered to the core metal portion by double-sided tape or adhesive. Also, the second layer is laminated on the first layer by double-sided tape or adhesive. This can prevent the first layer from coming into contact with air, as compared to an embodiment in which the first layer is sewn to the core metal portion, and therefore can prevent a decrease in accuracy. (3) In the steering device of the above aspect, a heater layer having an electric heating wire may be provided between the core metal portion and the covering portion, and the electric heating wire may be configured to be capable of passing electricity. For example, in a case where the first layer is not conductive and a conductive material is disposed between the coating and the core metal separately from the first layer, it is desirable that the conductive material be in contact with the coating in order to detect the capacitance. Therefore, when the steering device further includes a heater layer capable of generating heat, the heater layer is often disposed between the conductive material and the core metal. In this case, the heat of the heater layer may not be easily transmitted to the coating. According to the steering device of this form, since the heater layer is disposed between the coating and the core metal, the heat of the heater layer is easily transmitted to the coating. The temperature of the gripping part can be efficiently increased. (4) In the steering device of the above aspect, the first layer may be adhered to the heater layer by double-sided tape or an adhesive, and the second layer may be laminated to the first layer by double-sided tape or an adhesive. When the first layer having a conductive material comes into contact with air, the accuracy of the first layer as a detection electrode may decrease due to the low dielectric constant of air. According to the steering device of this embodiment, the first layer is adhered to the heater layer by double-sided tape or adhesive. Also, the second layer is laminated on the first layer by double-sided tape or adhesive. This makes it possible to suppress the first layer from coming into contact with air, as compared to an embodiment in which the first layer is simply laminated on the heater layer, and therefore to suppress a decrease in accuracy. The present disclosure may be realized in various forms other than a steering device, for example, a grip, a vehicle including a steering device, a manufacturing method for a steering device, a manufacturing method for a grip, etc. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of a steering device according to an embodiment of the present invention; [Diagram 2] Cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 4 is a block diagram showing the configuration of a control unit. [Figure 4] FIG. 11 is a cross-sectional view of a gripping portion according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: FIG. 1 is a schematic diagram of a steering device 1 of this embodiment. The steering device 1 is provided on a moving body. In this embodiment, the steering device 1 is provided on a vehicle. The steering device 1 is a device operated by a driver who is an occupant of the vehicle. The steering device 1 is connected to a rotation shaft AR of the vehicle and configured to be rotatable around an axis line AX of the rotation shaft AR. The rotation of the steering device 1 is transmitted to a steering gear box (not shown) via the rotation shaft AR. The direction along the axis line AX of the rotation shaft AR is expressed as the front-rear direction according to the traveling direction of the vehicle. Among the directions perpendicular to the axis line AX, the direction in which the steering device 1 stands is expressed as the up-down direction. The direction perpendicular to the axis line AX and the up-down direction is expressed as the left-right direction. The steering device 1 includes a gripping unit 10, a rotating unit 20, a detector 30, and a control unit 40.

[0009] The grip portion 10 is a portion that is gripped by the driver. In this embodiment, the grip portion 10 has a substantially annular shape when viewed in the front-rear direction. The grip portion 10 is connected to the rotating portion 20 on the inner circumferential side of the grip portion 10. The grip portion 10 covers a portion of the rotating portion 20. In this way, the grip portion 10 is connected to the rotating portion 20. The grip portion 10 has a core metal portion 110 and a covering portion 120. In FIG. 1, the core metal portion 110 is represented by a dashed line.

[0010] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. The core metal portion 110 is a portion that constitutes the framework of the gripping portion 10. As shown in FIG. 1, the core metal portion 110 sandwiches the rotating portion 20 when viewed in the front-rear direction. As shown in FIG. 2, the core metal portion 110 includes a core metal 111 and a core metal covering portion 112. The core metal 111 has an annular shape when viewed in the front-rear direction. The core metal 111 is formed of a metal and has electrical conductivity. The core metal 111 is formed of, for example, iron, aluminum, magnesium, or an alloy thereof. The core metal 111 is grounded. The core metal covering portion 112 covers the core metal 111. The core metal covering portion 112 is formed of an insulating material other than a metal. The core metal covering portion 112 can be formed by in-mold molding using, for example, a soft material such as polyurethane foam or an elastic material. The core metal covering portion 112 may be formed of a hard material.

[0011] The covering portion 120 covers the core metal portion 110. As shown in FIG. 2, the covering portion 120 is the outermost layer of the grip portion 10 and is a portion that is gripped by the driver. The covering portion 120 includes a first layer 121, a second layer 122, and a third layer 123. The first layer 121 functions as a capacitance sensor that detects capacitance generated between the grip portion 10 and the driver gripping the grip portion 10. The first layer 121 is electrically connected to the detector 30 via a lead wire LR shown in FIG. 1. The first layer 121 is conductive. As shown in FIG. 2, the first layer 121 is disposed at a position closer to the core metal portion 110 than the second layer 122 and the third layer 123. In this embodiment, the first layer 121 is bonded to the core metal portion 110 by a double-sided tape 50. The first layer 121 is formed by applying metal plating to a fiber fabric. In this embodiment, a synthetic fiber formed of polyester is used as the fiber fabric. The conductive material is selected from metals such as copper, nickel, tin, and silver.

[0012] The second layer 122 is a portion for making the driver who holds the grip portion 10 feel flexibility. The second layer 122 is disposed between the first layer 121 and the third layer 123. In this embodiment, the second layer 122 is laminated on the first layer 121 by the double-sided tape 51. The second layer 122 is formed of a material that is not conductive and has flexibility. In this embodiment, the second layer 122 is formed of PET (Polyethylene terephthalate). The third layer 123 protects the surface of the second layer 122. The third layer 123 is exposed to the outside of the grip portion 10 and is a portion that comes into contact with the driver. The third layer 123 is laminated on the second layer 122 by the double-sided tape 52. The third layer 123 is formed of a material that is not conductive. In this embodiment, the third layer 123 is formed of a paint containing a silicone resin, an acrylic resin, a urethane resin, or the like.

[0013] The rotating part 20 shown in Fig. 1 is rotatably attached to the vehicle. The rotating part 20 is disposed at a position surrounded by the grip part 10. The rotating part 20 has a shape having a space inside. In the space inside the rotating part 20, a detector 30, a control part 40, an airbag (not shown), various circuits, etc. are disposed.

[0014] The detector 30 detects the capacitance between the driver who holds the grip part 10 and the first layer 121. The detector 30 detects the change in the capacitance between the driver who holds the grip part 10 and the first layer 121 from the detected capacitance. The detector 30 includes various circuits such as an oscillation circuit, a resonance circuit, a detection circuit, and an amplification circuit, and detects the change in the capacitance. Specifically, when the grip part 10 is held by the driver, the capacitance between the first layer 121 as a detection electrode and the driver changes with respect to the capacitance when the grip part 10 is not held. In the detector 30, the resonance frequency that changes with the change in the capacitance is amplitude modulated. The original signal is extracted from the amplitude modulated signal, amplified, and output as a voltage. Information on the voltage value is transmitted from the detector 30 to the control unit 40.

[0015] Fig. 3 is a block diagram showing the configuration of the control unit 40. As shown in Fig. 3, the control unit 40 is composed of a CPU as a processor, a RAM, and a ROM. The ECU realizes various functions by executing a program installed in advance. The control unit 40 executes control of the steering device 1 based on a voltage value transmitted from the detector 30 and an instruction from an ECU (Electronic Control Unit) of the vehicle (not shown).

[0016] The control unit 40 determines the state of gripping of the grip portion 10 based on the capacitance detected by the detector 30. The control unit 40 determines whether or not the grip portion 10 is being gripped by the driver based on the capacitance detected by the detector 30. Specifically, the control unit 40 compares the voltage value of the detection result with a preset threshold value, and detects whether or not the grip portion 10 is being gripped based on the comparison result.

[0017] The control unit 40 further controls the airbag and notifies the driver, etc. When the driver's hand is released from the gripping unit 10 while the vehicle is running, the control unit 40 notifies the driver, etc., that the driver's hand has been released from the gripping unit 10 by a buzzer or the like via a speaker or monitor (not shown).

[0018] In the steering device 1 of this embodiment, since the first layer 121 has conductivity, the gripping state of the grip portion 10 is detected based on a change in the electrostatic capacitance of the first layer 121. Compared to an embodiment in which a conductive material is included in, for example, the second layer 122 formed of a flexible material, or the third layer 123 which is in contact with the driver as an occupant and therefore is easily exposed to air, it is possible to ensure the flexibility of the covering portion 120 and detect the gripping state without being affected by deterioration of the third layer 123.

[0019] The inventors of the present application found that the elasticity characteristics of a metal-plated fiber fabric are similar to those of the second layer 122 and the third layer 123. By using a metal-plated fiber fabric as the first layer 121, it is possible to suppress poor appearance caused by wrinkles due to differences in elasticity between the first layer 121 and the second layer 122, and deterioration of the function of the first layer 121 as a capacitance sensor.

[0020] Also, for example, the number of parts of the steering device 1 can be reduced compared to an embodiment in which a capacitance sensor is disposed between the covering portion 120 and the core metal portion 110 separately from the first layer 121. Therefore, the number of parts assembly steps can be reduced during the manufacture of the steering device 1. Human error and equipment malfunctions associated with the manufacture can be suppressed. Furthermore, since the configuration of the steering device 1 is reduced compared to an embodiment in which a capacitance sensor is disposed between the covering portion 120 and the core metal portion 110 separately from the first layer 121, the possibility of malfunctions occurring can be reduced.

[0021] When the first layer 121 having a conductive material comes into contact with air, the low dielectric constant of air may reduce the accuracy of the first layer 121 as a detection electrode. In the steering device 1 of this embodiment, the first layer 121 is adhered to the core metal portion 110 with a double-sided tape 50. In addition, the second layer 122 is laminated on the first layer 121 with a double-sided tape 51. This makes it possible to prevent the first layer 121 from coming into contact with air, and thus to prevent a decrease in accuracy, compared to, for example, a mode in which the first layer 121 is sewn to the core metal portion 110 or a mode in which the second layer 122 is laminated on the first layer 121.

[0022] B. Second embodiment: Fig. 4 is a cross-sectional view of a gripping portion 10B of the second embodiment. Fig. 4 corresponds to Fig. 2. The second embodiment differs from the first embodiment in that the gripping portion 10B includes a heater layer 60.

[0023] The heater layer 60 can raise the temperature of the grip portion 10 by generating heat when electricity is applied. The heater layer 60 is disposed between the core metal portion 110 and the covering portion 120. In this embodiment, the heater layer 60 is attached to the surface of the core metal portion 110 by a double-sided tape 53. The heater layer 60 is also bonded to the first layer 121 by a double-sided tape 54. In this embodiment, the heater layer 60 is formed by disposing an electric heating wire on a nonwoven fabric. The electric heating wire is configured to be capable of being energized by an electric wire (not shown). The energization is controlled by the control portion 40.

[0024] The control unit 40 of the second embodiment switches ON / OFF control of the power supply to the heater layer 60 based on the state of gripping of the gripping portion 10. For example, when it is determined that the gripping portion 10 is not being gripped by the driver, the control unit 40 switches the power supply to the heater layer 60 to OFF control. For example, when it is determined that the gripping portion 10 is being gripped for a predetermined number of seconds or more, the control unit 40 switches the power supply to the heater layer 60 to ON control.

[0025] For example, in a case where the first layer 121 is not conductive and a conductive material is disposed between the covering portion 120 and the core metal portion 110 separately from the first layer 121, it is desirable that the conductive material be in contact with the covering portion 120 in order to detect the capacitance. Therefore, when the steering device 1 further includes a heater layer 60 capable of generating heat, it is considered that the heater layer 60 is often disposed between the conductive material and the core metal portion 110. In this case, there is a possibility that the heat of the heater layer 60 is not easily transmitted to the covering portion 120. According to the steering device 1 of the second embodiment, since the heater layer 60 is disposed between the covering portion 120 and the core metal portion 110, the heat of the heater layer 60 is easily transmitted to the covering portion 120. The temperature of the grip portion 10 can be efficiently increased.

[0026] According to the steering device 1 of the second embodiment, the first layer 121 is adhered to the heater layer 60 by the double-sided tape 54. Similarly to the first embodiment, the second layer 122 is laminated on the first layer 121 by the double-sided tape 51. This makes it possible to prevent the first layer 121 from coming into contact with air, as compared to a mode in which the first layer 121 is simply laminated on the heater layer 60, for example, and therefore makes it possible to prevent a decrease in the accuracy of the first layer 121 as a detection electrode.

[0027] C. Other embodiments: C1. Alternative embodiment 1: (1) In the above embodiment, the steering device 1 is provided in a vehicle. Note that the steering device may be provided in a moving body other than a vehicle, such as a ship or an airplane.

[0028] (2) In the above embodiment, the grip portion 10 has a generally annular shape when viewed in the front-rear direction. For example, the grip portion may have a rectangular or trapezoidal shape when viewed in the front-rear direction. For example, the grip portion may have a generally rectangular shape that surrounds the rotating portion.

[0029] (3) In the above embodiment, the first layer 121 is formed by plating the surface of the fiber fabric with a metal. For example, the first layer may be formed of fabric woven with metal threads. For example, the first layer may be metal fibers such as steel wool, or may be a combination of metal threads and fiber fabric woven together. In an embodiment in which the surface of the fiber fabric is plated with a metal, stretchability is maintained compared to fabric woven with metal threads.

[0030] (4) In the above embodiment, a synthetic fiber made of polyester is used as the fiber fabric. Note that, for example, a synthetic fiber made of nylon, acrylic, polyurethane, etc. may be used as the fiber fabric, and natural fibers, plant fibers, animal fibers, etc. may be selected.

[0031] (5) For example, a combination of a first layer formed of a metal-plated fiber fabric and a non-first layer formed of a non-metal-plated fiber fabric may be disposed on the surface of the core metal portion. The metal-plated first layer may be disposed in a portion of the gripping portion that is likely to be gripped by an occupant, and the non-first layer may be disposed in other portions.

[0032] (6) In the above embodiment, the second layer 122 is made of PET (Polyethylene terephthalate). The second layer may be made of a rubber material, an elastomer material, or the like.

[0033] (7) In the above embodiment, the control unit 40 controls the airbag, notifies the driver, etc. For example, when the control unit determines that the gripping portion is not gripped for a certain period of time after the notification, the control unit may transmit a signal to the ECU to stop the vehicle.

[0034] (8) For example, the gripping portion may include a shield layer and an insulating layer between the first layer and the core metal portion. The shield layer is electrically connected to the first layer via a voltage follower circuit or the like, and is controlled to have the same potential as the first layer. Therefore, no charge is stored between the first layer and the shield layer, and it does not function as a capacitor. As a result, the shield layer can eliminate capacitance noise generated between the sensor layer and the core metal.

[0035] In the embodiment in which the gripping portion includes an insulating layer and a shielding layer, the insulating layer is an insulating flexible substrate disposed between the first layer and the shielding layer, and is made of a flexible thin film such as polyimide or PET.

[0036] C2. Alternative embodiment 2: (1) In the above embodiment, the first layer 121 is adhered to the core metal portion 110 by the double-sided tape 50, and the second layer 122 is laminated on the first layer 121 by the double-sided tape 51. For example, the first layer may be adhered to the core metal portion by an adhesive, and the second layer may be adhered to the core metal portion by an adhesive. The adhesive may be an elastomer material, a rubber material, or a material mainly composed of polyvinyl chloride or the like. For example, acrylic, styrene, silicon, olefin, urethane, and epoxy materials may be used as the elastomer material. For example, butadiene rubber, silicon rubber, ethylene propylene diene rubber, and chloroprene rubber may be used as the rubber material. In this embodiment, the first layer is prevented from coming into contact with air, as compared with an embodiment in which the first layer is sewn to the core metal portion, and therefore a decrease in accuracy can be suppressed.

[0037] (2) For example, the second layer may be laminated on the first layer with double-sided tape or adhesive, and the first layer may be sewn to the core metal portion. Alternatively, the first layer may be adhered to the core metal portion with double-sided tape or adhesive, and the second layer may be laminated on the first layer without using double-sided tape or adhesive. In this embodiment, the deterioration of the accuracy of the first layer as a detection electrode can be suppressed compared to the embodiment in which the first layer is sewn to the core metal portion and the second layer is laminated on the first layer.

[0038] (3) For example, the first layer may be bonded to the core metal portion by welding or an adhesive, and the second layer may be laminated to the first layer by welding or an adhesive.

[0039] C3. Alternative embodiment 3: (1) In the second embodiment, the heater layer 60 has an electric heating wire. Note that, for example, the heater layer may be formed of a flexible sheet material in which a heating element is disposed in a resin material.

[0040] (2) In the second embodiment, the control unit 40 switches ON / OFF control of the current supply to the heater layer 60 based on the gripping state of the gripping unit 10. Note that, for example, the control unit does not have to control the heater layer based on the gripping state of the gripping unit. For example, the control unit may continue to control the current supply to the heater layer to ON while the vehicle is running, and switch the current supply to the heater layer to OFF when the power of the vehicle is turned off.

[0041] C4. Alternative embodiment 4: (1) In the second embodiment, the first layer 121 is adhered to the heater layer 60 by the double-sided tape 54, and the second layer 122 is laminated on the first layer 121 by the double-sided tape 51. For example, the first layer may be adhered to the heater layer by an adhesive, and the second layer may be adhered to the core metal part by an adhesive. The adhesive may be an elastomer material, a rubber material, or a material mainly composed of polyvinyl chloride or the like. For example, acrylic, styrene, silicon, olefin, urethane, and epoxy materials can be used as the elastomer material. For example, butadiene rubber, silicon rubber, ethylene propylene diene rubber, and chloroprene rubber can be used as the rubber material. In this embodiment, the first layer can be prevented from coming into contact with air, as compared with an embodiment in which the first layer is simply laminated on the heater layer, and therefore the deterioration of the accuracy of the first layer as a detection electrode can be suppressed.

[0042] (2) For example, the second layer may be laminated on the first layer with double-sided tape or adhesive, and the first layer may be laminated on the heater layer without using double-sided tape or adhesive. Alternatively, the first layer may be attached to the core metal portion with double-sided tape or adhesive, and the second layer may be laminated on the first layer without using double-sided tape or adhesive. In this embodiment, the deterioration of the accuracy of the first layer as a detection electrode can be suppressed compared to the embodiment in which the first layer is laminated on the heater layer and the second layer is laminated on the first layer.

[0043] (3) For example, the first layer may be bonded to the heater layer by welding or an adhesive, and the second layer may be laminated to the first layer by welding or an adhesive.

[0044] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0045] 1... steering device, 10, 10B... gripping portion, 20... rotating portion, 30... detector, 40... control portion, 50, 51, 52, 53, 54... double-sided tape, 60... heater layer, 110... core portion, 111... core, 112... core covering portion, 120... covering portion, 121... first layer, 122... second layer, 123... third layer, AR... rotating shaft, AX... shaft line, LR... lead wire

Claims

1. A steering device provided on a moving body, A rotating part rotatably attached to the moving body; A grip portion connected to the rotating portion and gripped by an occupant; Equipped with The gripping portion is A core metal portion that sandwiches the rotating portion; a covering portion covering the core metal portion, the covering portion including a first layer, a second layer, and a third layer; Equipped with the first layer is disposed at a position closer to the core metal portion than the second layer and the third layer, and has electrical conductivity; the second layer is disposed between the first layer and the third layer and is made of a non-conductive, flexible material; the third layer is exposed to the outside at the grip portion and is formed of a non-conductive material; The steering device further comprises: a detector for detecting a change in capacitance between an occupant gripping the grip portion and the first layer; A control unit that determines a gripping state of the gripping unit based on a change in electrostatic capacitance detected by the detector; A steering device comprising:

2. 2. The steering device according to claim 1, the first layer is bonded to the core metal portion by a double-sided tape or an adhesive; The second layer is laminated to the first layer by double-sided tape or adhesive.

3. 2. The steering device according to claim 1, Further, a heater layer having an electric heating wire is provided between the core metal portion and the covering portion, A steering device, wherein the heating wire is configured to be electrically conductive.

4. 4. The steering device according to claim 3, the first layer is attached to the heater layer by double-sided tape or adhesive; The second layer is laminated to the first layer by double-sided tape or adhesive.

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