Sensor mat structure and steering device

Abstract

To suppress a gripping state from being erroneously sensed when a diver is not gripping a gripping part.SOLUTION: A sensor mat structure, which is provided on a gripping part of a steering device provided on a moving body, comprises a sensor part including a conductive cloth layer that is a layer made of a conductive cloth having conductivity, which senses a state of gripping of the gripping part by a driver, utilizing electrostatic capacitance between a hand of a driver of the moving body and the conductive cloth layer. The senor part has a first portion including the conductive cloth layer and a second portion including the conductive cloth layer, which is configured so that sensitivity in sensing a gripping state in the second portion is lower than sensitivity in sensing a gripping state in the first portion.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a sensor mat structure and a steering device. [Background technology]

[0002] There is known a technique for detecting whether a driver of a moving body is gripping a grip of a steering device provided in the moving body. For example, Patent Document 1 discloses a technique for detecting contact of the driver with the grip by using a sheet-like sensor provided in the grip of the steering device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-55420 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, if something other than the driver's hand, such as the driver's knee or thigh, comes into contact with the gripping portion, there is a risk that the gripping portion will be mistakenly detected as being gripped by the driver's hand, even though the gripping portion is not actually being gripped by the driver's hand. [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 mat structure to be provided in a grip portion of a steering device of a vehicle. The sensor mat structure includes a sensor unit including a conductive cloth layer, which is a layer of conductive cloth having electrical conductivity, for detecting a grip of the grip portion by the driver of the vehicle using electrostatic capacitance between the driver's hand and the conductive cloth layer. The sensor unit has a first portion including the conductive cloth layer and a second portion including the conductive cloth layer, and is configured so that the sensitivity of the grip detection in the second portion is lower than the sensitivity of the grip detection in the first portion. According to this embodiment, by positioning the second part in a part of the grip portion that is likely to be touched by something other than the driver's hand, it is possible to prevent false detection of gripping when the driver is not gripping the grip portion. (2) In the above embodiment, the first portion may be disposed on the front side of the grip portion, and the second portion may be disposed on the back side of the grip portion. This embodiment can suppress false detection of gripping caused by the driver's knees or thighs touching the back side of the grip portion. (3) In the above embodiment, the second part may be disposed in a lower part of the grip part that is located below a reference plane that includes the rotation axis of the grip part and is parallel to the left-right direction of the moving body in a basic state in which the steering device specifies a straight direction as the traveling direction of the moving body. According to this embodiment, it is possible to suppress erroneous detection of gripping caused by the driver's knees or thighs touching the lower part of the grip part. (4) In the above embodiment, the second portion may be disposed in the basic state in an angular range from 4 o'clock to 8 o'clock about the rotation axis, when the direction directly above the rotation axis when viewed from the front side of the grip is defined as 0 o'clock. This embodiment can more effectively prevent erroneous detection of gripping caused by the driver's knees or thighs touching the lower part of the grip. (5) In the above embodiment, the first part may be disposed in an upper part of the gripping part that is located above the reference plane in the basic state. This embodiment can both suppress erroneous grip detection in the lower part and properly detect grip in the upper part. (6) In the above embodiment, the first portion may be disposed in the basic state in an angular range from 10 o'clock to 2 o'clock about the rotation axis, when the direction directly above the rotation axis when the gripping portion is viewed from the front side of the gripping portion is defined as 0 o'clock. This embodiment can more effectively suppress false detection of a grip in the lower portion and detect a proper grip in the upper portion at the same time. (7) In the above embodiment, the roughness of the conductive cloth in the second portion may be greater than the roughness of the conductive cloth in the first portion. According to this embodiment, by making the roughness of the conductive cloth in the second portion greater or by making the roughness of the conductive cloth in the first portion finer, the detection sensitivity in the second portion can be easily made lower than the detection sensitivity in the first portion. (8) In the above embodiment, the conductive cloth is made of fibers having a core material and a conductive layer located around the core material, and the conductive layer in the first portion has a copper layer containing copper as a main component, and the conductive layer in the second portion has a layer containing a metal material having a lower conductivity than copper as a main component, and may not have the copper layer. According to this embodiment, by not providing a copper layer in the fibers constituting the conductive cloth in the second portion, it is possible to easily make the detection sensitivity in the second portion lower than the detection sensitivity in the first portion. (9) In the above embodiment, the sensor unit may have a surface layer portion laminated on the outside of the conductive cloth layer in the grip portion and having insulating properties, the first portion and the second portion may include the surface layer portion, and the thickness of the surface layer portion in the second portion may be thicker than the thickness of the surface layer portion in the first portion. According to this embodiment, by making the thickness of the surface layer portion in the second portion thicker or by making the thickness of the surface layer portion in the first portion thinner, it is possible to easily make the detection sensitivity in the second portion lower than the detection sensitivity in the first portion. In addition to the above-described sensor mat structure, the present disclosure can be realized in various forms, such as a steering device, a moving body, a method for manufacturing a sensor mat structure, and a method for manufacturing a steering device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a grip detection system according to a first embodiment. [Figure 2] FIG. 1 is a first explanatory diagram showing a schematic configuration of a steering device according to a first embodiment. [Figure 3] FIG. 2 is a second explanatory diagram showing a schematic configuration of the steering device according to the first embodiment. [Figure 4] IV-IV cross-sectional view of FIGS. 2 and 3. FIG. [Figure 5] FIG. 3 is a diagram illustrating a first conductive cloth and a second conductive cloth in the first embodiment. [Figure 6] FIG. 6 is an explanatory diagram showing a steering device according to a second embodiment. [Figure 7] FIG. 10 is an explanatory view showing first fibers and second fibers in a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a grip portion in a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: 1 is an explanatory diagram showing a schematic configuration of a grip detection system 50 according to a first embodiment. The grip detection system 50 is provided in a vehicle 10 as a moving body. The vehicle 10 includes a steering device 100.

[0009] The grip detection system 50 is used to detect gripping of the steering device 100 by the driver DR of the vehicle 10. "Grabbing of the steering device 100" specifically means gripping of the grip portion 120, which will be described later. In addition, in the present disclosure, "grasping" does not only mean the driver DR gripping the grip portion 120 with his / her hand, but also includes the driver DR's hand coming into contact with the grip portion 120. The grip detection system 50 includes a touch sensor 200 and a detection device 250. Details of the touch sensor 200 and the detection device 250 will be described later.

[0010] The vehicle 10 may be, for example, a passenger car, a bus, or a truck. The vehicle 10 includes a driving actuator that generates a propulsive force for the vehicle 10, a braking actuator that generates a braking force for the vehicle 10, a steering actuator that changes the direction of travel of the vehicle 10, and a driving control device 30 that controls these. The driving control device 30 has two operating modes: a manual driving mode and an automatic driving mode. In the manual driving mode, the driving control device 30 controls the driving actuator, the braking actuator, and the steering actuator in response to the driver's operation of the accelerator pedal, the brake pedal, and the steering device 100, thereby causing the vehicle 10 to travel. In the automatic driving mode, the driving control device 30 automatically controls at least one of the driving actuator, the braking actuator, and the steering actuator, thereby causing the vehicle 10 to travel. By automatically controlling each actuator in this manner, the driving control device 30 can achieve automatic driving levels 1 to 5 defined by the Society of Automotive Engineers (SAE). For example, when transitioning from automated driving to manual driving, the driving control device 30 requests the driver DR to hold the grip portion 120. Note that automated driving from level 1 to level 2 defined by the SAE is also called driving assistance.

[0011] The steering device 100 includes a steering unit 105. The steering unit 105 is operated by a driver DR seated in a driver's seat DS to specify the traveling direction of the vehicle 10. That is, the steering device 100 specifies the traveling direction of the vehicle 10 by the steering unit 105.

[0012] FIG. 2 is a first explanatory diagram showing a schematic configuration of the steering device 100. FIG. 3 is a second explanatory diagram showing a schematic configuration of the steering device 100. As shown in FIGS. 2 and 3 , the steering unit 105 includes a central portion 110, a connecting portion 115, and a grip portion 120. The central portion 110 constitutes a central part of the steering unit 105. The central portion 110 is configured to be rotatable about a rotation axis AX of the steering unit 105. In this embodiment, the central portion 110 is fixed to a steering shaft 25 provided in the vehicle 10. The central portion 110 is also referred to as a hub portion. The grip portion 120 is gripped by the driver DR. The grip portion 120 is located outside the central portion 110 when viewed along the rotation axis AX. The grip portion 120 is also referred to as a rim portion. In this embodiment, the outer shape of the grip portion 120 is circular, but is not limited thereto and may be, for example, a D-shape or a rectangular shape. The connecting portion 115 connects the central portion 110 and the grip portion 120. The connecting portion 115 is also referred to as a spoke portion. With this configuration, the grip portion 120 is configured to be rotatable around the rotation axis AX in conjunction with the rotation of the central portion 110 around the rotation axis AX. In other words, the rotation axis AX corresponds to the rotation axis of the central portion 110 and the rotation axis of the grip portion 120.

[0013] 1 to 3 show the steering unit 105 and the grip unit 120 in a basic state. The basic state refers to a state in which the steering device 100 indicates a straight-ahead direction MF as the traveling direction of the vehicle 10. Hereinafter, the straight-ahead direction MF is also referred to as the forward direction, and the direction opposite to the straight-ahead direction MF is also referred to as the rearward direction. Forward and rearward are collectively referred to as the "front-rear direction of the vehicle 10." The front-rear direction of the vehicle 10 is also simply referred to as the "front-rear direction." In addition, in this disclosure, the left-right direction of the vehicle 10 corresponds to the left-right direction when the vehicle 10 is viewed from the rear to the front of the vehicle 10. The left-right direction of the vehicle 10 is also simply referred to as the "left-right direction." Furthermore, FIG. 1 shows an upward direction MU among the up-down directions of the vehicle 10. Hereinafter, unless otherwise specified, each part of the steering device 100 will be described assuming that the steering device 100 is in the basic state.

[0014] 1 to 3 also show arrows along the mutually orthogonal X, Y, and Z directions. The X, Y, and Z directions are directions along the X, Y, and Z axes, which are three mutually orthogonal spatial axes, and each includes both a direction on one side of the X, Y, and Z axes and an opposite direction. Specifically, the positive directions along the X, Y, and Z axes are the +X direction, +Y direction, and +Z direction, respectively, and the negative directions along the X, Y, and Z axes are the -X direction, -Y direction, and -Z direction, respectively. The X axis is an axis along the rotation axis AX. The X axis extends in the fore-and-aft direction of the vehicle 10, with the +X direction side inclined downward with respect to the straight-ahead direction MF. Of the X directions, the +X direction is the direction from the rear to the front of the vehicle 10, and the -X direction is the direction from the front to the rear of the vehicle 10. The Y axis is an axis along the left-right direction. Of the Y directions, the direction from left to right of the vehicle 10 is the +Y direction, and the direction from right to left of the vehicle 10 is the -Y direction. The Z axis extends in the vertical direction of the vehicle 10, with the +Z direction side tilted forward with respect to the upward direction MU. Of the Z directions, the +Z direction is the direction from the bottom to the top of the vehicle 10, and the -Z direction is the direction from the top to the bottom of the vehicle 10. In other figures, arrows along the X, Y, and Z directions, the straight-forward direction MF, and the upward direction MU are also appropriately depicted. The X, Y, and Z directions, the straight-forward direction MF, and the upward direction MU in Figures 1 to 3 represent the same directions as the X, Y, and Z directions in other figures. Furthermore, in this specification, "orthogonal" includes a range of 90°±10°.

[0015] 1 to 3 also show a first plane P1, a second plane P2, and a third plane P3, which are imaginary planes. The first plane P1 is a plane that includes the rotation axis AX and is parallel to the Z direction. The second plane P2 is a plane that includes the rotation axis AX and is parallel to the left-right direction. Hereinafter, the second plane P2 will also be referred to as the reference plane. The third plane P3 is a plane that passes through the center of the grip portion 120 in the X direction and is perpendicular to the rotation axis AX. The first plane P1 to the third plane P3 are also shown in other figures as appropriate.

[0016] As shown in FIGS. 1 to 3, the grip portion 120 has an upper portion US and a lower portion LS. The upper portion US is a portion of the grip portion 120 located above the second plane P2. The lower portion LS is a portion of the grip portion 120 located below the second plane P2. The steering unit 105 also has a front side Fs and a rear side Bs. The front side Fs is the side of the steering unit 105 that is closer to the driver's seat DS and the driver DR. The rear side Bs is the side of the steering unit 105 that is farther from the driver's seat DS and the driver DR. In other words, the rear side Bs is the side opposite the front side Fs across the third plane P3. The front side Fs and rear side Bs of the steering unit 105 correspond to the front side and rear side of the grip portion 120, respectively. FIG. 2 shows the steering device 100 as viewed from the front side Fs of the steering unit 105. FIG. 3 shows the steering device 100 as viewed from the rear side Bs of the steering section 105.

[0017] In the following, the angular position and angular range of the grip portion 120 in the basic state when viewed from the front Fs side may be expressed in terms of a clockwise direction centered on the rotation axis AX. In this disclosure, the direction directly upward from the rotation axis AX when viewing the grip portion 120 from the front Fs side is defined as the 0 o'clock direction in the clockwise direction. The 0 o'clock direction and the 12 o'clock direction coincide with each other. Figure 3 shows the angular positions of the grip portion 120 as a 0 o'clock position PC0, a 2 o'clock position PC2, a 4 o'clock position PC4, a 3 o'clock position PC3, a 6 o'clock position PC6, an 8 o'clock position PC8, a 9 o'clock position PC9, and a 10 o'clock position PC10. The 0 o'clock position PC0, the 2 o'clock position PC2, the 3 o'clock position PC3, the 4 o'clock position PC4, the 6 o'clock position PC6, the 8 o'clock position PC8, the 9 o'clock position PC9, and the 10 o'clock position PC10 are positions corresponding to the 0 o'clock direction, the 2 o'clock direction, the 3 o'clock direction, the 4 o'clock direction, the 6 o'clock direction, the 8 o'clock direction, the 9 o'clock direction, and the 10 o'clock direction, respectively.

[0018] The steering unit 105 is provided with a touch sensor 200. Moreover, as shown in FIG. 2, in this embodiment, the steering unit 105 is further provided with a detection device 250. Specifically, the detection device 250 is provided in the central unit 110. That is, the components of the grip detection system 50 in this embodiment are integrated into the steering device 100. In other embodiments, the detection device 250 may be provided in any part inside or outside the steering device 100, not limited to being provided in the central unit 110. Moreover, the detection device 250 may be disposed, for example, separately from the steering device 100. Note that the detection device 250 is omitted in FIG. 3.

[0019] The touch sensor 200 is configured as a capacitance-type touch sensor and is configured to be able to measure capacitance. The capacitance measured by the touch sensor 200 changes depending on the degree of contact between the hand of the driver DR and the grip portion 120. The touch sensor 200 is used to detect the grip of the grip portion 120 by the driver DR, using the capacitance measured in this manner. Hereinafter, grip detection using the touch sensor 200 will also be simply referred to as "grip detection." Details of grip detection will be described later.

[0020] As shown in FIG. 2, the touch sensor 200 includes a sensor unit 210 and a sensor circuit 220. The sensor unit 210 is electrically connected to the sensor circuit 220. The sensor unit 210 includes a conductive cloth layer 125 and a surface layer 127 having a skin layer 126. The conductive cloth layer 125 is made of conductive cloth. The conductive cloth is a fabric fabric that has been surface-treated with metal plating. More specifically, the conductive cloth in this embodiment is formed by weaving metal-plated conductive fibers around a resin core material. The conductive cloth layer 125 and the surface layer 127 will be described in detail below. Note that the sensor circuit 220 is omitted from FIG. 3.

[0021] The detection device 250 is configured by a computer including a processor 251, a memory 252, an input / output interface 253, and an internal bus. The processor 251, the memory 252, and the input / output interface 253 are connected via the internal bus to enable bidirectional communication. The touch sensor 200 and the operation control device 30 are connected to the input / output interface 253 via wired or wireless communication. The processor 251 functions as a detection unit by executing a computer program PG pre-stored in the memory 252. The detection unit performs grip detection using the capacitance measured by the touch sensor 200. Note that at least a portion of the functions of the detection device 250 may be realized by, for example, a hardware circuit.

[0022] The processor 251 may output information according to the result of the grip detection via, for example, an output device (not shown) provided in the vehicle 10. For example, the processor 251 may alternatively output a detection result of a hands-on state in which the driver DR grips the grip portion 120, or a detection result of a hands-off state in which the driver DR is not gripping the grip portion 120. Furthermore, the processor 251 may output information for instructing the driver DR to grip the grip portion 120 when the driver DR is in a hands-off state, for example, when transitioning from autonomous driving to manual driving. The output device is, for example, a display, a speaker, or the like provided in the vehicle 10.

[0023] 4 is a cross-sectional view taken along line IV-IV of FIGS. 2 and 3. As shown in FIG. 4, the grip portion 120 has a substantially circular cross-sectional shape. The grip portion 120 has a core portion 121, a heater layer 122, and a sensor mat structure 201. The sensor mat structure 201 includes a sensor portion 210. In this embodiment, the sensor mat structure 201 further includes a shield layer 123 and an insulating layer 124. The sensor mat structure 201 constitutes at least a part of the touch sensor 200 described above.

[0024] In the grip portion 120, a heater layer 122, a shield layer 123, an insulating layer 124, a conductive cloth layer 125, and a skin layer 126 are laminated on the metal core 121 in this order from the side closest to the metal core 121. As a result, as shown in FIG. 4 , when a cross section of the grip portion 120 is viewed along the circumferential direction Dc of the grip portion 120, the metal core 121, the heater layer 122, the shield layer 123, the insulating layer 124, the conductive cloth layer 125, and the skin layer 126 are arranged from the inside to the outside of the grip portion 120. The layers of the grip portion 120 are joined by joints 129. The joints 129 are formed, for example, by insulating double-sided tape or an insulating adhesive. Note that in other embodiments, the heater layer 122 may be omitted.

[0025] The core metal portion 121 is a part that forms the skeleton of the grip portion 120. The core metal portion 121 has an overall annular shape along the circumferential direction Dc. The core metal portion 121 is composed of a core metal and a core metal covering portion (neither of which is shown). The core metal is made of a metal material such as iron or aluminum, and is conductive. The core metal is also grounded. The core metal covering portion is made of a soft material or an elastic material such as polyurethane foam, and is arranged to cover the periphery of the core metal.

[0026] The heater layer 122 is configured to be able to generate heat when electricity is applied thereto. The heater layer 122 is used to increase the temperature of the gripping part 120. The heater layer 122 is configured, for example, by a flexible sheet-like heating element.

[0027] The shield layer 123 is made of conductive cloth. The shield layer 123 is electrically connected to the conductive cloth layer 125 via the sensor circuit 220. The sensor circuit 220 controls the shield layer 123 so that it has the same potential as the conductive cloth layer 125. By disposing the shield layer 123 between the core and the conductive cloth layer 125, no capacitance is generated between the conductive cloth layer 125 and the core. Furthermore, by disposing the shield layer 123 between the heater layer 122 and the conductive cloth layer 125, no capacitance is generated between the heater layer 122 and the conductive cloth layer 125. As a result, the shield layer 123 can suppress capacitance noise. The noise here refers to capacitance generated in the conductive cloth layer 125 regardless of whether the driver DR grips the grip portion 120.

[0028] The insulating layer 124 is made of an insulating material that has no electrical conductivity, and is preferably made of a flexible insulating material such as polyethylene terephthalate.

[0029] As described above, the surface layer 127 is laminated on the outer side of the conductive cloth layer 125 in the grip portion 120. The surface layer 127 has insulating properties. In this embodiment, the surface layer 127 has a skin layer 126 and a bonding layer 129a. The skin layer 126 is exposed to the outside of the grip portion 120 and is gripped by the driver DR. The skin layer 126 is made of an insulating material that is not conductive. Specifically, the skin layer 126 is made of, for example, natural leather or synthetic leather. The bonding layer 129a is made of a bonding portion 129 provided between the skin layer 126 and the conductive cloth layer 125.

[0030] The sensor unit 210 is used for grip detection using the capacitance between the driver's hand and the conductive cloth layer 125. Specifically, the conductive cloth layer 125 functions as one electrode of a capacitor in the touch sensor 200. The driver's hand corresponds to the other electrode of the capacitor in the touch sensor 200. When the driver's hand touches the epidermal layer 126, capacitance is generated between the two electrodes of the touch sensor 200, i.e., between the conductive cloth layer 125 and the driver's hand. The capacitance generated between the two electrodes of the touch sensor 200 varies depending on the degree of contact between the driver's hand and the grip unit 120. Specifically, the capacitance of the sensor unit 210 varies depending on the distance between the driver's hand and the conductive cloth layer 125 and the contact area of ​​the driver's hand with the epidermal layer 126.

[0031] 2 is configured to acquire a change in capacitance between conductive cloth layer 125 and the hand of driver DR as a change in voltage and transmit the acquired voltage value to detection device 250. Detection device 250 detects that grip portion 120 is being gripped, for example, when the voltage value is equal to or greater than a predetermined threshold, i.e., when the magnitude of the change in capacitance detected by sensor circuit 220 is equal to or greater than a predetermined level. Furthermore, as described above, sensor circuit 220 is configured to eliminate capacitance noise by controlling conductive cloth layer 125 and shield layer 123 to the same potential.

[0032] As shown in FIGS. 2 to 4 , the sensor unit 210 has a first portion 211 and a second portion 212. The first portion 211 and the second portion 212 each include a conductive cloth layer 125. The conductive cloth layer 125 in the first portion 211 is also referred to as a first conductive cloth layer 131. The conductive cloth layer 125 in the second portion 212 is also referred to as a second conductive cloth layer 132. The sensor unit 210 is configured so that the grip detection sensitivity in the second portion 212 is lower than the grip detection sensitivity in the first portion 211. In this embodiment, as shown in FIGS. 2 and 4 , the first portion 211 is located on the front side Fs of the grip unit 120. As shown in FIGS. 3 and 4 , the second portion 212 is located on the back side Bs of the grip unit 120.

[0033] FIG. 5 is a diagram illustrating the first conductive cloth CC1 and the second conductive cloth CC2. The first conductive cloth CC1 is a conductive cloth constituting the first conductive cloth layer 131. The second conductive cloth CC2 is a conductive cloth constituting the second conductive cloth layer 132. In this embodiment, the first conductive cloth layer 131 and the second conductive cloth layer 132 are each made of different conductive cloths. In this embodiment, the second conductive cloth CC2 has a coarser surface than the first conductive cloth CC1. That is, as shown in FIG. 5, the opening size of the mesh MS2 of the second conductive cloth CC2 is larger than the opening size of the mesh MS1 of the first conductive cloth CC1. More specifically, in this embodiment, the mesh MS1 and the mesh MS2 have a square shape, and the diameter dm2 of the mesh MS2 is larger than the diameter dm1 of the mesh MS1. Note that the mesh MS1 and the mesh MS2 are each made of the same conductive fiber CF. Because the second conductive cloth CC2 is coarser than the first conductive cloth CC1, the area of ​​the second conductive cloth layer 132 that functions as one electrode of the capacitor is smaller in the second portion 212. Therefore, when the driver DR touches the first portion 211 and the second portion 212 under the same conditions, the change in capacitance that occurs in the second portion 212 is smaller than the change in capacitance that occurs in the first portion 211.

[0034] The grip detection sensitivity in the second portion 212 is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the grip detection sensitivity in the first portion 211. The grip detection sensitivity magnification here corresponds to the magnification of the amount of change in capacitance occurring in the second portion 212 relative to the amount of change in capacitance occurring in the first portion 211 when the driver DR's hand touches the first portion 211 and the second portion 212 under the same conditions. In the present embodiment, the roughness of the second conductive cloth CC2 and the roughness of the first conductive cloth CC1 are preferably set so as to realize such a difference in grip detection sensitivity. Specifically, it is preferable that the roughness of the second conductive cloth CC2 and the first conductive cloth CC1 be set so that the area of ​​the conductive fiber CF per unit area of ​​the second conductive cloth CC2 is, for example, 1.1 times or more, 1.2 times or more, or 1.3 times or more the area of ​​the conductive fiber CF per unit area of ​​the first conductive cloth CC1.

[0035] According to the sensor mat structure 201 of the present embodiment described above, the sensor unit 210 is configured so that the sensitivity of grip detection in the second portion 212 is lower than the sensitivity of grip detection in the first portion 211. As a result, when a foreign object other than the driver DR's hand, such as the driver's knee, thigh, umbrella, or plastic bag, touches the second portion 212, the grip portion 120 is less likely to be erroneously detected as being gripped, compared to when the foreign object touches the first portion 211. Therefore, by positioning the second portion 212 in a portion of the grip portion 120 that is likely to be touched by a foreign object, it is possible to prevent erroneous detection of gripping when the driver DR is not gripping the grip portion 120. Furthermore, because the sensitivity of grip detection in the first portion 211 is higher than that in the second portion 212, the first portion 211 can appropriately detect gripping of the grip portion 120 by the driver DR's hand. In this way, in this embodiment, appropriate grip detection can be achieved by differentiating the sensitivity of grip detection in the first part 211 and the second part 212 due to differences in the physical configuration of the sensor unit 210, without requiring complex control such as varying the threshold values ​​for gripping and non-gripping depending on the position of the gripping portion 120.

[0036] Furthermore, in the present embodiment, the first portion 211 is disposed on the front surface Fs of the grip portion 120, and the second portion 212 is disposed on the back surface Bs of the grip portion 120. Therefore, it is possible to suppress erroneous detection of gripping caused by the driver's knees or thighs touching the back surface Bs of the grip portion 120. In particular, for example, in the autonomous driving mode, the driver DR may not need to operate various pedals, and the driver DR may easily cross his / her legs. Here, as described above, because the +X direction side of the X axis is inclined with respect to the straight-ahead direction MF, when the driver DR crosses his / her legs, the driver's knees or thighs are likely to touch the back surface Bs of the grip portion 120. Therefore, in the present embodiment, for example, when the driver DR is required to grip the grip portion 120 during a transition from autonomous driving to manual driving, it is possible to effectively perform grip detection while suppressing erroneous detection of gripping.

[0037] In the present embodiment, the second conductive cloth CC2 has a roughness greater than that of the first conductive cloth CC1. Therefore, by making the second conductive cloth CC2 rougher, the grip detection sensitivity in the second portion 212 can be easily made lower than the grip detection sensitivity in the first portion 211.

[0038] B. Second embodiment: Fig. 6 is an explanatory diagram showing a steering device 100b in a second embodiment. Similar to Fig. 2, Fig. 6 shows the steering device 100b when viewed from the front Fs side of the steering unit 105. In the second embodiment, unlike the first embodiment, the second portion 212b of the sensor unit 210b is arranged in the lower portion LS of the grip portion 120 in the basic state. Portions of the configurations of the steering device 100b and the sensor mat structure 201b in the second embodiment that are not particularly described are the same as those in the first embodiment.

[0039] In the basic state, the second portion 212b is disposed in a first angle range AR1. The first angle range AR1 represents an angular range extending clockwise from the 4 o'clock position PC4 to the 8 o'clock position PC8. That is, in the basic state, the second portion 212b is disposed in an angular range extending from the 4 o'clock direction to the 8 o'clock direction about the rotation axis AX. The first angle range AR1 includes the 4 o'clock position PC4 and the 8 o'clock position PC8.

[0040] In this embodiment, the first portion 211b is disposed in the upper portion US of the grip portion 120 in the basic state. More specifically, the first portion 211b is disposed in the second angle range AR2 in the basic state. The second angle range AR2 represents an angle range extending clockwise from the 10 o'clock position PC10 to the 2 o'clock position PC2. That is, the first portion 211b is disposed in the angle range from the 10 o'clock direction to the 2 o'clock direction about the rotation axis AX in the basic state. The second angle range AR2 includes the 10 o'clock position PC10 and the 2 o'clock position PC2. The upper portion US is a portion that is easily grasped when the driver DR assumes an appropriate driving posture and is a portion that is preferably grasped by the driver DR during manual driving. Of these, the second angle range AR2 is a portion that is particularly preferably grasped by the driver DR during manual driving.

[0041] According to the sensor mat structure 201b in the second embodiment described above, the second portion 212b is disposed in the lower portion LS of the grip portion 120. Therefore, it is possible to suppress erroneous detection of gripping caused by the knees or thighs of the driver DR touching the lower portion LS. In particular, in this embodiment, the second portion 212b is disposed in the first angle range AR1 in the basic state. Therefore, it is possible to more effectively suppress erroneous detection of gripping.

[0042] Furthermore, in this embodiment, the first portion 211b is disposed in the upper portion US of the gripping unit 120 in the basic state. Therefore, it is possible to both suppress erroneous detection of a grip in the lower portion LS and detect an appropriate grip in the upper portion US. In particular, in this embodiment, the first portion 211b is disposed in the second angle range AR2 in the basic state. Therefore, it is possible to more effectively both suppress erroneous detection of a grip in the lower portion LS and detect an appropriate grip in the upper portion US.

[0043] C. Third embodiment: FIG. 7 is an explanatory diagram showing the first fibers CF1 and the second fibers CF2 in the third embodiment. FIG. 7 shows cross sections of the first fibers CF1 and the second fibers CF2. The first fibers CF1 are the conductive fibers CF that constitute the first conductive cloth CC1 in the third embodiment. The second fibers CF2 are the conductive fibers CF that constitute the second conductive cloth CC2 in the third embodiment. In the third embodiment, unlike the first embodiment, the first conductive cloth CC1 and the second conductive cloth CC2 are each formed of different conductive fibers CF, thereby realizing a lower grip detection sensitivity in the second portion 212 than the grip detection sensitivity in the first portion 211. Also, in the third embodiment, unlike the first embodiment, the roughness of the first conductive cloth CC1 and the roughness of the second conductive cloth CC2 are the same. Portions of the steering device 100 and the sensor mat structure 201 in the third embodiment that are not specifically described are similar to those in the first embodiment.

[0044] The first fiber CF1 and the second fiber CF2 each have a resin core material CM and a conductive layer covering the core material CM. The conductive layer is formed by metal plating the core material CM. The first fiber CF1 has a first conductive layer CL1 as the conductive layer. The first conductive layer CL1 has a copper layer CuL. The copper layer CuL is a layer containing copper as a main component. The main component of a layer refers to a substance contained in the layer whose mass fraction is 50% or more. In this embodiment, the first conductive layer CL1 further has a nickel layer NiL. The nickel layer NiL is a layer containing nickel as a main component. In the first fiber CF1, the copper layer CuL is laminated on the core material CM so as to cover the core material CM from the outside. The nickel layer NiL is laminated on the copper layer CuL so as to cover the core material CM and the copper layer CuL from the outside. The nickel layer NiL covers the copper layer CuL from the outside in this manner, thereby suppressing corrosion of the copper layer CuL.

[0045] The second fiber CF2 has a second conductive layer CL2 as a conductive layer. The second conductive layer CL2 has a layer containing, as a main component, a conductor having a conductivity lower than that of copper, and does not have a copper layer CuL. In this embodiment, the second conductive layer CL2 has a nickel layer NiL. Because the second conductive layer CL2 does not have the copper layer CuL, when the driver DR's hand touches the first portion 211 and the second portion 212 under the same conditions, the charge generated in the second portion 212 is smaller than the charge generated in the first portion 211. As a result, the change in capacitance generated in the second portion 212 is smaller than the change in capacitance generated in the first portion 211.

[0046] According to the sensor mat structure 201 of the third embodiment described above, the first conductive layer CL1 of the first conductive cloth CC1 has a copper layer CuL. The second conductive cloth CC2 has a layer containing, as a main component, a conductor having a lower conductivity than copper, specifically a nickel layer NiL, but does not have a copper layer CuL. Therefore, by not providing the copper layer CuL in the second fibers CF2 that constitute the second conductive cloth CC2, it is possible to easily make the grip detection sensitivity of the second portion 212 lower than the grip detection sensitivity of the first portion 211.

[0047] D. Fourth embodiment: FIG. 8 is a cross-sectional view of the grip portion 120 in the fourth embodiment. Unlike the first embodiment, in the fourth embodiment, the thickness Th1 of the second surface layer 150 of the sensor unit 210d is greater than the thickness Th2 of the first surface layer 140. The second surface layer 150 is the surface layer 127 of the second portion 212. The first surface layer 140 is the surface layer 127 of the first portion 211. Unlike the first embodiment, in the fourth embodiment, the thickness Th2 is greater than the thickness Th1, thereby realizing a lower grip detection sensitivity in the second portion 212 than the grip detection sensitivity in the first portion 211. Also, unlike the first embodiment, in the fourth embodiment, the roughness of the first conductive cloth CC1 and the roughness of the second conductive cloth CC2 are the same. Portions of the steering device 100 and the sensor mat structure 201d in the fourth embodiment that are not specifically described are similar to those in the first embodiment.

[0048] In this embodiment, the first surface layer portion 140 includes a first surface layer 141 as the surface layer 126 and a first bonding layer 142 as the bonding layer 129a. The second surface layer portion 150 includes a second surface layer 151 as the surface layer 126 and a second bonding layer 152 as the bonding layer 129a. As shown in FIG. 8 , in this embodiment, the second bonding layer 152 is thicker than the first bonding layer 142, thereby realizing that the thickness Th2 is thicker than the thickness Th1. Because the thickness Th2 is thicker than the thickness Th1, the distance between the second conductive cloth layer 132, which functions as one electrode of the capacitor, and the hand of the driver DR, which functions as the other electrode, is greater in the second portion 212. Therefore, when the driver DR's hand touches the first portion 211 and the second portion 212 with the same contact area, the change in capacitance occurring in the second portion 212 is smaller than the change in capacitance occurring in the first portion 211. In other embodiments, for example, instead of or in addition to second bonding layer 152 being thicker than first bonding layer 142, second skin layer 151 may be thicker than first skin layer 141, thereby making thickness Th2 thicker than thickness Th1. Alternatively, second skin layer portion 150 may include an insulating layer different from second skin layer 151 and second bonding layer 152, thereby making thickness Th2 thicker than thickness Th1.

[0049] Furthermore, in this embodiment, thickness Th3b of second insulating layer 124b is thinner than thickness Th3a of first insulating layer 124a by an amount corresponding to the difference between thickness Th2 and thickness Th1, so that the radius of first gripping portion GL1, which corresponds to first portion 211 of gripping portion 120, and the radius of second gripping portion GL2, which corresponds to second portion 212 of gripping portion 120, are configured to be approximately the same. First insulating layer 124a is the insulating layer 124 of first gripping portion GL1. Second insulating layer 124b is the insulating layer 124 of second gripping portion GL2. As a result, the radius of second gripping portion GL2 is prevented from increasing due to the difference between thickness Th2 and thickness Th1. In other embodiments, the same radius of the first gripping portion GL1 and the second gripping portion GL2 may be achieved in other ways in addition to or instead of adjusting the thickness of the insulating layer 124 in the first gripping portion GL1 and the second gripping portion GL2. For example, the same radius of the first gripping portion GL1 and the second gripping portion GL2 may be achieved by adjusting the thickness of the shielding layer 123 in the first gripping portion GL1 and the second gripping portion GL2, or by adding a layer inside the conductive cloth layer 125 in at least one of the first gripping portion GL1 and the second gripping portion GL2. In this case, the additional layer is, for example, an insulating layer made of the same material as the insulating layer 124.

[0050] According to the sensor mat structure 201d in the fourth embodiment described above, the thickness Th2 of the second surface layer 150 is greater than the thickness Th1 of the first surface layer 140. Therefore, by making the thickness Th2 of the second surface layer 150 thicker or by making the thickness Th1 of the first surface layer 140 thinner, the sensitivity of grip detection in the second portion 212 can be easily made lower than the sensitivity of detection in the first portion 211.

[0051] E. Other Embodiments: (E1) In the second embodiment described above, the second portion 212b is arranged in the first angle range AR1 in the basic state, but may be arranged in an angle range of the lower portion LS that is different from the first angle range AR1.

[0052] (E2) In the second embodiment, the first portion 211b is disposed in the upper portion US. However, the first portion 211b may be disposed in the lower portion LS, for example. For example, the second portion 212b may be disposed on the lower surface of the lower portion LS, and the first portion 211b may be disposed on the upper surface of the lower portion LS. Even in this case, it is possible to suppress erroneous detection of gripping caused by the knees or thighs of the driver DR touching the grip portion 120.

[0053] (E3) In the second embodiment, the outer shape of grip portion 120 may be different from a circular shape, for example, a D-shape or a square shape. That is, when the outer shape of grip portion 120 is different from a circular shape, second portion 212b may be disposed in lower portion LS in the basic state. In this case, second portion 212b may be disposed in first angle range AR1 in the basic state. Even in these cases, it is possible to suppress erroneous detection of a grip caused by the knees or thighs of driver DR touching grip portion 120. Furthermore, when the outer shape of grip portion 120 is different from a circular shape, first portion 211b may be disposed in upper portion US in the basic state. In this case, first portion 211b may be disposed in second angle range AR2 in the basic state. Even in these cases, it is possible to suppress erroneous detection of a grip in lower portion LS and properly detect a grip in upper portion US.

[0054] (E4) The second portion 212 may be disposed at a position different from the lower portion LS or the back surface Bs side of the grip portion 120. For example, if the grip portion 120 has a portion on its upper portion US or front surface Fs side that has a shape that allows a plastic bag handle or an umbrella handle to be easily hung, the second portion 212 may be disposed at that portion. Even in this case, it is possible to prevent erroneous detection of gripping when the driver DR is not gripping the grip portion 120.

[0055] (E5) In each of the above embodiments, the lower sensitivity of grip detection in the second portion 212 than the sensitivity of grip detection in the first portion 211 may be achieved, for example, by a combination of any two or three of the difference in roughness of the conductive cloth described in the first embodiment, the difference in the conductive layer of the conductive fiber CF described in the third embodiment, and the difference in thickness of the surface layer 127 described in the fourth embodiment.

[0056] (E6) In the above embodiments, the vehicle 10 is shown as an example of a moving body. However, the moving body is not limited to the vehicle 10 and may be various moving bodies. For example, the moving body may be various moving bodies that are equipped with the steering device 100 and on which a passenger can ride, such as a ship, an airplane, a spaceship, or a so-called flying car.

[0057] 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]

[0058] 10...vehicle, 25...steering shaft, 30...drive control device, 50...grip detection system, 100, 100b...steering device, 105...steering section, 110...center section, 115...connection section, 120...grip section, 121...core section, 122...heater layer, 123...shield layer, 124...insulating layer, 124a...first insulating layer, 124b...second insulating layer, 125...conductive cloth layer, 126...surface layer, 127...surface layer section, 129...joint section, 129a...joint layer, 131...first conductive cloth layer, 132...second conductive cloth layer, 140...first surface layer portion, 141...first skin layer, 142...first bonding layer, 150...second surface layer portion, 151...second skin layer, 152...second bonding layer, 200...touch sensor, 201, 201b, 201d...sensor mat structure, 210, 210b, 210d...sensor portion, 211, 211b...first portion, 212, 212b...second portion, 220...sensor circuit, 250...detection device, 251...processor, 252...memory, 253...input / output interface

Claims

1. A sensor mat structure provided in a grip portion of a steering device provided in a moving body, a sensor unit including a conductive cloth layer that is a layer of conductive cloth having electrical conductivity, the sensor unit detecting the grip of the grip portion by the driver of the vehicle by utilizing electrostatic capacitance between the driver's hand and the conductive cloth layer; The sensor unit a first portion including the conductive fabric layer and a second portion including the conductive fabric layer; A sensor mat structure configured such that the sensitivity of detecting the grip in the second portion is lower than the sensitivity of detecting the grip in the first portion.

2. The sensor mat structure according to claim 1, A sensor mat structure, wherein the first portion is disposed on a front side of the grip portion and the second portion is disposed on a rear side of the grip portion.

3. The sensor mat structure according to claim 1, A sensor mat structure in which the second part is positioned in a lower part of the gripping part that is located below a reference plane that includes the rotation axis of the gripping part and is parallel to the left-right direction of the moving body when the steering device specifies a straight-ahead direction as the direction of travel of the moving body.

4. The sensor mat structure according to claim 3, A sensor mat structure in which, in the basic state, the second part is positioned in an angular range from 4 o'clock to 8 o'clock around the rotation axis, when the direction directly above the rotation axis when the gripping portion is viewed from the front side of the gripping portion is defined as 0 o'clock.

5. The sensor mat structure according to claim 3, A sensor mat structure in which, in the basic state, the first portion is arranged in an upper portion of the gripping portion that is located above the reference plane.

6. The sensor mat structure according to claim 5, A sensor mat structure in which, in the basic state, the first part is positioned in an angular range from 10 o'clock to 2 o'clock around the rotation axis, when the direction directly above the rotation axis when the gripping portion is viewed from the front side of the gripping portion is defined as 0 o'clock.

7. The sensor mat structure according to claim 1, A sensor mat structure, wherein the roughness of the conductive cloth in the second portion is greater than the roughness of the conductive cloth in the first portion.

8. The sensor mat structure according to claim 1, The conductive cloth is made of fibers having a core material and a conductive layer that covers the periphery of the core material, the conductive layer in the first portion includes a copper layer containing copper as a main component, A sensor mat structure, wherein the conductive layer in the second portion has a layer containing, as a main component, a conductor having a conductivity lower than that of copper, and does not have the copper layer.

9. 9. The sensor mat structure according to claim 1, the sensor unit has a surface layer portion laminated on the outer side of the conductive cloth layer in the grip portion, the surface layer portion having insulating properties; the first portion and the second portion include the surface layer portion, A sensor mat structure, wherein the thickness of the surface layer in the second portion is greater than the thickness of the surface layer in the first portion.

10. A steering device provided on a moving body, a grip portion configured to be rotatable around a rotation axis and gripped by a driver of the moving body; a sensor unit provided on the grip portion, the sensor unit including a conductive cloth layer that is a layer of conductive cloth having electrical conductivity, the sensor unit detecting the grip of the grip portion by the driver by utilizing electrostatic capacitance between the driver's hand and the conductive cloth layer; the sensor unit has a first portion including the conductive fabric layer and a second portion including the conductive fabric layer, A steering device configured such that the sensitivity of detecting the grip in the second portion is lower than the sensitivity of detecting the grip in the first portion.

Images