Steering system

Abstract

We are searching for a steering system that can accurately detect the gripping state of the steering wheel. [Solution] The steering device includes a capacitive sensor unit 60 having an electrode 61 provided on the rim unit 30 to detect the gripping motion of the rim unit 30 by the occupant. The rim unit 30 has a core metal 31 that forms the skeleton of the rim unit 30 and a skin 33 that covers the rim unit 30 around its entire circumference. When the rim unit 30 is cut perpendicular to the reference line CL1, the area on the hub side of the cross-section of the rim unit 30 is defined as the inner diameter side region AR1, and the area on the opposite side of the inner diameter side region AR1 is defined as the outer diameter side region AR2. The electrode 61 is located between the core metal 31 and the skin 33 and extends circumferentially into the inner diameter side region AR1.

Description

Technical Field

[0001] The present invention relates to a steering device capable of detecting the gripping state of a steering wheel.

Background Art

[0002] In recent years, efforts have been actively made to provide access to a sustainable transportation system that takes into account people in vulnerable positions among transportation participants. In order to achieve this, research and development on driving support technologies have been carried out. Under such a background, a device is known in which a capacitance sensor is provided in the rim portion of a steering wheel, and the gripping state of the rim portion by a driver is detected by the capacitance sensor (see, for example, Patent Document 1).

[0003] In the device described in Patent Document 1, a conductive portion that functions as a contact sensor is provided over the entire circumference of the rim portion, and a blank portion is provided in the lower portion in the circumferential direction of the rim portion where the conductive portion is cut off or notched so that the contact sensitivity decreases.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even if a blank portion is provided in the lower portion in the circumferential direction of the rim portion as described in Patent Document 1 above, depending on the posture of the occupant, the tilt operation of the steering wheel, and the rotation position of the steering wheel, etc., the body of the occupant may contact the rim portion outside the blank portion, and in that case, there is a risk of false detection that the rim portion is gripped.

Means for Solving the Problems

[0007] According to the present invention, the gripping state of the steering wheel can be detected with high accuracy. [Brief explanation of the drawing]

[0008] [Figure 1] A side view showing a schematic configuration near the driver's seat of a vehicle having a steering device according to an embodiment of the present invention. [Figure 2] Viewpoint II in Figure 1. [Figure 3] A cross-sectional view along line III-III in Figure 2. [Figure 4A] A front view of the steering wheel rim, showing the gripping motion by the occupant. [Figure 4B] Cross-sectional view of the main part, Figure 4A. [Figure 5] Figure 3 shows a cross-sectional view of the main part of the rim. [Figure 6A] A cross-sectional view of the main part of the substrate showing an example in which recesses for positioning electrodes are provided on the surface of the substrate in the rim portion. [Figure 6B] A cross-sectional view of the main part of the rim, showing an example in which recesses for positioning electrodes are provided on the surface of the base material of the rim. [Figure 7]A block diagram showing the control configuration of a steering device according to an embodiment of the present invention. [Figure 8] A flowchart showing an example of the process executed by the controller in Figure 7. [Figure 9] A diagram illustrating the positional relationship between the steering wheel and the occupant's lower limbs. [Figure 10] Front view showing a modified version of the rim section. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to Figures 1 to 10. The steering device according to the embodiment of the present invention is mounted on a vehicle. The vehicle is, for example, an autonomous vehicle having an automatic driving function that does not require driving operations by a driver. The vehicle may also be a manually driven vehicle that requires driving operations by a driver. Below, an example in which the steering device is applied to an autonomous vehicle will be described. This autonomous vehicle is configured to be able to switch between an autonomous driving mode that does not require driving operations by a driver and a manual driving mode that requires driving operations by a driver.

[0010] Figure 1 is a side view showing a schematic configuration near the driver's seat of a vehicle 1 having a steering device 100 according to an embodiment of the present invention. In the following, the front-rear direction, left-right direction, and up-down direction are defined as shown in the figure, and the configuration of each part will be described according to these definitions. The front-rear direction, left-right direction, and up-down direction correspond to the front-rear direction (length direction), left-right direction (width direction), and up-down direction (height direction) of the vehicle 1.

[0011] Figure 1 shows a vehicle 1 with an occupant PS seated in the driver's seat 2. As shown in Figure 1, the steering device 100 has a steering wheel 10 positioned facing the driver's seat 2 and operated by the occupant PS. The steering wheel 10 is supported at the tip (rear end) of a steering shaft 11 that extends from the front to the rear of the vehicle, inclined upward along the centerline CL0. The steering shaft 11 rotates integrally with the steering wheel 10 in response to the operation of the steering wheel 10.

[0012] Although detailed illustrations are omitted, the steering device 100 includes a telescopic mechanism 12 and a tilt mechanism 13. The steering wheel 10 is movable in the forward / backward direction (direction of arrow A in Figure 1) by the telescopic mechanism 12 and in the vertical direction by the tilt mechanism 13. This allows the occupant PS to move the steering wheel 10 to any position. The telescopic mechanism 12 and the tilt mechanism 13 are driven by manual operation by the occupant. At least one of the telescopic mechanism 12 and the tilt mechanism 13 may be driven by an actuator (e.g., an electric motor).

[0013] Inside the vehicle, for example, a camera 14 having an image sensor such as a CCD or CMOS is installed above the front windshield. The camera 14 captures images of the occupant PS, and based on the image signals acquired by the camera 14, the occupant PS's physique and posture can be recognized.

[0014] Figure 2 is a front view of the steering wheel 10 (viewpoint II in Figure 1). As shown in Figure 2, the steering wheel 10 has a hub portion 20 connected to the steering shaft 11, a substantially annular rim portion 30 arranged around the hub portion 20, and spoke portions 40 connecting the hub portion 20 and the rim portion 30. The center line CL0 passes through the center of the hub portion 20 (for example, the center of the hub portion 20), and the steering wheel 10 extends along a plane perpendicular to the center line CL0. Hereinafter, the direction along a circle centered on the center line CL0 is defined as the circumferential direction, and the direction extending radially from the center line CL0 is defined as the radial direction.

[0015] The rim portion 30 extends along a circular or substantially circular reference line CL1 centered on the center line CL0. The rim portion 30 is not limited to circular or substantially circular, and may be rectangular or substantially rectangular. The rim portion 30 is gripped by the occupant PS, and the steering wheel 10 is operated via the rim portion 30. The spoke portion 40 is three spokes extending leftward, rightward, and downward from the hub portion 20. The number of the spoke portions 40 may be two or four, and the configuration of the spoke portion 40 is not limited to that shown.

[0016] The rim portion 30 exhibits the same cross-sectional shape over the entire circumference. FIG. 3 is a cross-sectional view (a cross-sectional view taken along line III-III in FIG. 2) of the rim portion 30 cut perpendicular to the reference line CL1. The reference line CL1 is located at the center of the cross-section of the rim portion 30. In FIG. 3, a straight line L1 extending along a plane FS1 passing through the reference line CL1 and perpendicular to the center line CL0, and a straight line L2 (a straight line perpendicular to the straight line L1) passing through the reference line L1 and parallel to the center line CL0 are shown. The straight line L2 extends in a downward gradient in the front-rear direction, more specifically in the forward direction, and extends along a substantially cylindrical curved surface CS1 centered on the center line CL0.

[0017] As shown in FIG. 3, the rim portion 30 has a core metal 31, a base material 32, and a skin 33. The core metal 31 is provided at the central portion of the rim portion 30. The core metal 31 is formed of a highly rigid metal material such as stainless steel. The core metal 31 extends along the reference line CL1 and constitutes a skeleton portion forming the skeleton of the rim portion 30. In FIG. 3, the core metal 31 is shown as having a substantially circular cross-section, but the core metal 31 may be in a pipe shape, or may be in a shape bent into a substantially C shape or U shape.

[0018] The base material 32 has a substantially cylindrical cross-section. The base material 32 is formed to surround the entire outer surface of the core metal 31 and defines the overall shape of the rim portion 30. The base material 32 is made of a material with lower rigidity than the core metal 31 (for example, a resin material such as non-conductive polyurethane) and constitutes the base of the rim portion 30. The outer skin 33 covers the entire outer surface of the base material 32, and the surface of the outer skin 33 is exposed to the outside. That is, the outer skin 33 constitutes an outer skin that covers the entire circumference of the rim portion 30 in the circumferential direction. When an occupant grips the rim portion 30, the occupant's hand comes into contact with the outer skin 33. The outer skin 33 is made of a resin material, leather, wood, etc.

[0019] In Figure 3, the region AR1 of the cross-section of the rim portion 30, which is radially inward from the curved surface CS1 (straight line L2), i.e., on the side of the center line CL0, is called the inner diameter region, and the region AR2, which is radially outward from the curved surface CS1, i.e., on the opposite side of the center line CL0, is called the outer diameter region. Furthermore, the region in front of the plane FS1 (straight line L1) is called the front region AR3, and the region behind the plane FS1 (occupant side) is called the rear region AR4. The front region AR3 is the region on the base end side of the steering shaft 11, and the rear region AR4 is the region on the tip side of the steering shaft 11.

[0020] The steering device 100 according to this embodiment further includes a capacitive sensor unit 60 that detects the gripping motion of the rim portion 30 by the occupant. The sensor unit 60 includes a power supply (not shown), an electrode 61 provided on the rim portion 30, and a detection circuit 42 (Figure 7) that detects the capacitance of the electrode 61 or a change in capacitance. The detection circuit 42 detects, for example, the electrical characteristics of the electrode 61, that is, the magnitude of the capacitance between the electrode 61 and the ground (vehicle body). The capacitance detected by the detection circuit 42 increases when the object to be detected (occupant's body) approaches the electrode 61 and decreases when it moves away.

[0021] As shown in Figure 3, the electrode 61 is located between the base material 32 and the skin 33, and is interposed over the entire inner diameter region AR1 and anterior region AR3 of the rim portion 30. In other words, the electrode 61 is positioned on the opposite side from the occupant's lower limbs and on the opposite side from the occupant's abdomen. The electrode 61 is positioned along the outer circumferential surface of the base material 32, and the whole thing has a quarter-circle shape. As shown by the dotted line in Figure 2, one end of a pair of signal wires 45 is connected to the electrode 61. The signal wire 45 is routed inside the spoke portion 40 along the spoke portion 40, and the other end is connected to the detection circuit 42.

[0022] Figure 4A is a front view (viewed from the occupant's side, i.e., from the rear) of the rim portion 30 showing the gripping action by the occupant, and Figure 4B is a cross-sectional view of the main part of Figure 4A. For convenience, the hub portion 20 and spoke portion 40 of the steering wheel 10 are omitted from Figure 4A.

[0023] As shown in Figures 4A and 4B, when an occupant grips the rim portion 30, the area of ​​the occupant's palm from the CM joint to the MP joint and the thenar eminence (referred to as the wrist-side region AR10) are mainly located in the outer diameter region AR2 of the rim portion 30. On the other hand, the area from the base of the fingers to the fingertips (referred to as the finger-side region AR20) is mainly located in the inner diameter region AR1. At this time, the finger-side region AR20 approaches the electrode 61. This increases the capacitance of the electrode 61, making it possible to detect the occupant's gripping motion of the steering wheel 10.

[0024] In particular, since the electrode 61 is positioned in the inner diameter region AR1 of the rim portion 30 facing the finger-side region AR20 of the occupant's hand, it is possible to accurately detect when the occupant is gripping the steering wheel 10 (rim portion 30). In other words, since the electrode 61 is not present in the outer diameter region AR2, even if the occupant's lower limbs or other parts come into contact with the rim portion 30, the sensor portion 60 can be prevented from falsely detecting this contact.

[0025] Figure 5 is a cross-sectional view of the main part of the rim portion 30 in Figure 3, showing the configuration of the electrode 61 in more detail. As shown in Figure 5, the electrode 61 has a pair of substantially thin plate-shaped electrode layers (inner electrode layer 611, outer electrode layer 612) and an insulating layer 613 interposed between the pair of electrode layers 611 and 612.

[0026] Adhesive (adhesive portion) 63 is applied to the outer surface of the base material 32, forming an adhesive layer. The inner electrode layer 611 is bonded to the outer surface of the base material 32 via the adhesive 63 over the entire circumference of the rim portion 30 in the inner diameter side region AR1 and the front side region AR3 in Figure 3. The outer electrode layer 612 is positioned facing the inner surface of the surface layer 33 so as to face the entire area of ​​the inner electrode layer 611.

[0027] In this embodiment, the electrode 61 is provided only in a portion of the circle centered on the reference line CL1 (the inner diameter region AR1 and the front region AR3) (Figure 3). As a result, the area of ​​the electrode 61 is smaller compared to the case where the electrode 61 is provided around the entire circumference of the circle centered on the reference line CL1. Therefore, the detection sensitivity of the sensor unit 60 tends to be lower. However, since the electrode 61 is constructed by interposing an insulating layer 613 between the pair of electrode layers 611 and 612, the decrease in the detection sensitivity of the sensor unit 60 can be suppressed.

[0028] In this embodiment, the electrodes 61 are laminated and mounted on the surface of the base material 32. This makes it easier to mount the electrodes 61 compared to the case where the electrodes 61 are provided inside the rim portion 30 by insert molding, and reduces the manufacturing cost of the steering wheel 10 having the electrodes 61. In addition, the signal wires 45 (Figure 2) connected to the electrodes 61 are routed along the spoke portion 40. This makes it easier to route the signal wires 45 compared to the case where the electrodes 61 are provided inside the rim portion 30 by insert molding.

[0029] As described above, the electrode 61 is fixed by adhesion to the outer surface of the base material 32. However, in this embodiment, if the temperature of the external environment changes and the base material 32 expands and compresses, there is a risk that the electrode 61 may shift in position. Therefore, a recessed locking portion that restricts the position of the electrode 61 may be provided to prevent the electrode 61 from shifting. Figure 6A schematically shows one such example.

[0030] As shown in Figure 6A, the outer circumferential surface of the base material 32 is provided with a recess 35 with a depth corresponding to the thickness of the electrode 61, and locking portions 36 that protrude in the circumferential direction so as to cover both circumferential ends of the recess 35. When placing the electrode 61 in the recess 35, first, one end of the electrode 61 is inserted into the locking portion 36 on the circumferential end side of the recess 35 while bending the electrode 61. Next, the other end of the electrode 61 is inserted into the locking portion 36 on the circumferential end side of the recess 35. This allows the entire electrode 61 to be placed in the recess 35, as shown by the dotted line in Figure 6A.

[0031] Figure 6B is a cross-sectional view showing the arrangement of the electrode 61 in Figure 6A in more detail. As shown in Figure 6B, the electrode 61 (inner electrode layer 611, insulating layer 613, outer electrode layer 612) is placed in the recess 35 via adhesive 63. When the electrode 61 is placed in the recess 35, both circumferential ends of the electrode 61 are covered by the locking portion 36. This restricts the position of the electrode 61 and prevents displacement of the electrode 61. After the electrode 61 is placed in the recess 35, the electrode 61 and the locking portion 36 are covered by the skin 33.

[0032] Figure 7 is a block diagram showing the control configuration of the steering device 100 according to this embodiment. As shown in Figure 7, the steering device 100 includes a sensor unit 60, a camera 14, a controller 50, a notification device 55, and an automatic driving system 56. The notification device 55 is a device for notifying the occupant of a request to grip the steering wheel 10, and is composed of a speaker and a monitor.

[0033] Signals from the detection circuit 42 and the camera 14 are input to the controller 50. The controller 50 is configured to include a computer having a CPU, ROM, RAM, and other peripheral circuits. The controller 50 has functions as a threshold setting unit 51, a determination unit 52, and an output unit 53.

[0034] The threshold setting unit 51 recognizes the build and posture of the occupant based on the image signal acquired by the camera 14. Then, based on the recognized build and posture, a threshold value Ca for determining the gripping of the steering wheel 10 is set. The threshold setting unit 51 calculates the shortest distance from the lower limb part or abdomen of the occupant to the steering wheel 10 based on the recognized build and posture of the occupant, and sets the threshold value Ca to a larger value as the distance becomes smaller. That is, the threshold value Ca is increased as the lower limb part or the like approaches the occupant.

[0035] The determination unit 52 determines whether the capacitance C detected via the detection circuit 42 is greater than or equal to the threshold value Ca set by the threshold setting unit 51. When the capacitance C is greater than or equal to the threshold value Ca (C≥Ca), the determination unit 52 determines that the steering wheel 10 is being gripped. On the other hand, when the capacitance C is less than the threshold value Ca (C<Ca), the determination unit 52 determines that the steering wheel 10 is not being gripped.

[0036] The output unit 53 outputs the determination result by the determination unit 52 to the notification device 55 and the automatic driving system 56. In addition to this, the output unit 53 communicates with the automatic driving system 56 and determines whether a gripping request for the steering wheel 10 is output from the automatic driving system 56. When a gripping request is output from the automatic driving system 56, a signal is output to the notification device 55 to notify the occupant to grip the steering wheel 10.

[0037] The autonomous driving system 56, for example, while the vehicle 1 is driving in autonomous driving mode, determines whether it is necessary to switch the driving mode from autonomous driving mode to manual driving mode based on the conditions around the vehicle 1 and the condition of the vehicle itself. If it determines that it is necessary to switch from autonomous driving mode to manual driving mode (for example, when changing the autonomous driving level from level 3 to level 2), the autonomous driving system 56 outputs a request to grip the steering wheel 10.

[0038] Figure 8 is a flowchart showing an example of a process executed by the CPU of the controller 50 according to a pre-stored program. The process shown in this flowchart is initiated, for example, when the vehicle 1 is driving in automatic driving mode and the automatic driving system 56 outputs a request to grip the steering wheel 10; that is, when the notification device 55 notifies the driver of a request to grip the steering wheel 10, the process is started and repeated at predetermined intervals. Regardless of whether or not a grip request is output, the process shown in the flowchart may also be started when the power switch of the vehicle 1 is turned on.

[0039] First, in step S1, the controller 50 reads signals from the sensor unit 60 (detection circuit 42) and the camera 14. Next, in step S2, the controller 50 recognizes the occupant's physique and posture based on the image signal from the camera 14 and sets a threshold Ca according to the occupant's physique and posture. Next, in step S3, the controller 50 determines whether the capacitance C detected by the sensor unit 60 is greater than or equal to the threshold Ca.

[0040] If the result in step S3 is positive, the process proceeds to step S4; otherwise, it proceeds to step S5. In step S4, a grip signal indicating that the steering wheel 10 has been gripped is output to the notification device 55 and the automatic driving system 56. This stops the notification of the request to grip the steering wheel 10.

[0041] Meanwhile, in step S5, a non-gripping signal indicating that the steering wheel 10 is not being gripped is output to the notification device 55 and the automated driving system 56. The notification device 55 continues to notify of the gripping request as long as the non-gripping signal is output. If the gripping signal is not output (the occupant does not grip the steering wheel 10) despite the notification device 55 notifying of the gripping request for a predetermined time, the automated driving system 56 performs a predetermined operation of the vehicle 1 (for example, a stopping operation).

[0042] The operation of the steering device 100 according to this embodiment can be summarized as follows. When driving in automatic driving mode, if it becomes necessary to switch to manual driving mode, the notification device 55 notifies the driver of a request to grip the steering wheel 10. As a result, the occupant (driver) grips the steering wheel 10. When the steering wheel 10 is gripped, the capacitance C detected by the sensor unit 60 increases, and the capacitance C becomes greater than or equal to the threshold Ca. As a result, a grip signal is output to the automatic driving system 56, and the driving mode is switched to manual driving mode (step S4).

[0043] In this case, the electrodes 61 of the sensor unit 60 are provided in the inner diameter region AR1 and the front region AR3 of the rim portion 30 (Figure 3). Therefore, when the occupant grips the rim portion 30, the finger-side region AR20 (Figure 4A) approaches the electrodes 61, and the capacitance C detected by the sensor unit 60 increases. This allows for accurate detection of the gripping motion of the steering wheel 10.

[0044] Figure 9 schematically shows the positional relationship between the steering wheel 10 and the occupant's lower limb PS1. As shown in Figure 9, the occupant's lower limb PS1 is closest to region ARa, which is the outer diameter region AR2 and the rear region AR4 at the bottom of the steering wheel 10. In this embodiment, the electrode 61 is not provided in this region ARa, but is provided in region ARb, which is the inner diameter region AR1 and the front region AR3, furthest from the lower limb PS1. Therefore, the occupant is not present in the direction of the electric field lines of the electrode 61 indicated by the arrow, and it is possible to prevent false detection of gripping the steering wheel 10 due to parts of the occupant other than their palms approaching the steering wheel 10.

[0045] In the above example, a single electrode 61 is provided around the entire circumference of the rim portion 30, but multiple electrodes 61 may be provided in the circumferential direction. Figure 10 is a front view (viewed from the rear) of the rim portion 30 showing an example of this configuration. As shown in Figure 10, the electrode 61 is divided into four equal parts by axes CL11, CL12, CL13, and CL14 that extend radially outward from the center line CL0. Therefore, four electrodes 61A, 61B, 61C, and 61D (dotted lines) are provided in the inner diameter region AR1 and the front region AR3 (Figure 3) of the rim portion 30 in the circumferential direction.

[0046] Each electrode 61A to 61D is connected to a separate detection circuit 42 (Figure 7), and the steering device 100 in Figure 10 has four sensor units 60. This makes it possible to determine not only whether the steering wheel 10 is gripped, but also which area of ​​the steering wheel 10 in the circumferential direction is gripped. In Figure 10, the electrode 61 is divided into four parts in the circumferential direction, but it may also be divided into two, three, or five or more parts to provide multiple electrodes 61 in the circumferential direction. If the electrode 61 is divided into multiple parts in the circumferential direction, it does not have to be divided evenly in the circumferential direction.

[0047] This embodiment can provide the following effects and advantages. (1) The steering device 100 for a vehicle includes a hub portion 20 connected to a steering shaft 11, a rim portion 30 that extends around the hub portion 20 along a substantially circular reference line CL1 over the entire circumference of the hub portion 20 and is gripped by the occupant, and spoke portions 40 that connect the hub portion 20 and the rim portion 30 (Figures 1 and 2). The steering device 100 further includes a capacitive sensor portion 60 having electrodes 61 provided on the rim portion 30 to detect the gripping motion of the occupant on the rim portion 30 (Figure 7). The rim portion 30 includes a core metal 31 that forms the skeleton of the rim portion 30 and a skin 33 that covers the rim portion 30 over the entire circumference (Figure 3). When the rim portion 30 is cut perpendicular to the reference line CL1, the region on the hub portion 20 side of the cross-section of the rim portion 30 is defined as the inner diameter region AR1, and the region opposite to the inner diameter region AR1 is defined as the outer diameter region AR2. In this case, the electrode 61 is located between the core metal 31 and the outer skin 33, and extends circumferentially into the inner diameter region AR1 (Figures 3, 4A).

[0048] By providing the electrodes 61 in the inner diameter region AR1 of the rim portion 30 in this manner, it is possible to prevent the steering wheel 10 from being mistakenly detected as being gripped by the occupant when the occupant's lower limbs come into contact with the steering wheel 10. The electrodes 61 are provided around the entire circumference of the rim portion 30, eliminating the need to provide a blank area without electrodes 61 in a part of the circumferential direction of the steering wheel 10. This simplifies the construction of the steering wheel 10. Since the electrodes 61 are located in the inner diameter region AR1 of the rim portion 30 in any circumferential region of the steering wheel 10, the gripping state of the steering wheel 10 can be accurately detected regardless of the occupant's posture, the tilting motion of the steering wheel 10, and the rotational position of the steering wheel 10.

[0049] (2) The electrode 61 extends circumferentially to the front region AR3 of the vehicle 1, which is on the base end side of the steering shaft 11, within the inner diameter region AR1 of the cross-section of the rim portion 30 (Figures 3 and 4A). By providing the electrode 61 in the front region AR3, which is furthest from the occupant, within the inner diameter region AR1 of the rim portion 30, false detection of gripping actions when something other than the occupant's palm comes into contact with the steering wheel 10 can be effectively prevented.

[0050] (3) The rim portion 30 further has a base material 32 that surrounds the core metal 31 around its entire circumference (Figure 2). The electrode 61 has an inner electrode layer 611 mounted on the surface of the base material 32, an outer electrode layer 612 positioned facing the inner electrode layer 611 and on the surface 33, and an insulating layer 613 interposed between the inner electrode layer 611 and the outer electrode layer 612 (Figure 5). This makes it easier to provide the electrode 61 in the rim portion 30 compared to when the electrode 61 is embedded in the rim portion 30 by insert molding.

[0051] (4) The steering device 100 further includes an adhesive 63 provided on the surface of the base material 32 for bonding the inner electrode layer 611 (Figure 5). This makes the process of attaching the electrodes 61 easier and reduces the manufacturing cost of the steering device 100.

[0052] (5) The base material 32 has a concave locking portion 36 that locks the circumferential end of the electrode 61 (Figures 6A, 6B). This prevents displacement of the electrode 61 when the base material 32 expands and compresses due to changes in the temperature of the external environment.

[0053] (6) The sensor unit 60 further has a signal line 45 which has one end electrically connected to the electrode 61 and extends along the spoke unit 40 (Figure 2). This makes it easy to route the signal line 45.

[0054] (7) The steering device 100 further includes a camera 14 for detecting the occupant's physique and posture, a determination unit 52 for determining whether the rim portion 30 is being gripped based on the magnitude of the capacitance detected via the electrode 61 and a threshold Ca, and a threshold setting unit 51 for setting the threshold Ca according to the occupant's physique and posture detected by the camera 14 (Figures 1 and 7). This makes it possible to accurately determine whether the steering wheel 10 is being gripped regardless of the occupant's physique or posture.

[0055] (8) The electrodes 61 may be a plurality of electrodes 61 (61A, 61B, 61C, 61D) arranged on the rim portion 30, divided into a plurality in the circumferential direction (Figure 10). In this case, the controller 50 further has the function of a gripping area identification unit that identifies the gripping area of ​​the rim portion 30 by the occupant in response to signals from the plurality of electrodes 61. With this configuration, it is possible to identify which circumferential area of ​​the steering wheel 10 the occupant is gripping.

[0056] This embodiment can be modified into various forms. Several modifications are described below. In the above embodiment, electrodes 61 are provided in the inner diameter side region AR1 and the front side region AR3 of the rim portion 30, extending over the entire circumferential region of the rim portion 30 centered on the center line CL0. However, as long as they are provided in the inner diameter side region AR1 of the rim portion 30, some or all of the electrodes 61 may be provided in the rear side region AR4. Electrodes 61 may be provided in a part of the circumferential region centered on the center line CL0. In the above embodiment, electrodes 61 are provided in a quarter-circle region of the cross-section of the rim portion 30 centered on the reference line CL1. However, as long as they are provided in at least the inner diameter side region AR1, electrodes 61 may be provided in a region narrower or wider than a quarter-circle.

[0057] In the above embodiment, the rim portion 30 extends along the reference line CL1, which is a substantially circular closed curve, around the entire circumference of the hub portion 20. However, the overall shape of the rim portion 30, i.e., the shape of the closed curve (predetermined shape), is not limited to a circle. In the above embodiment, the electrode 61 is composed of an inner electrode layer 611 (first electrode layer) and an outer electrode layer 612 (second electrode layer) facing each other via an insulating layer 613. However, the configuration of the electrode is not limited to that described above. In the above embodiment, the inner electrode layer 611 is bonded to the surface of the base material 32 via an adhesive 63. However, the electrode 61 may be provided on the rim portion 30 by other methods. In the above embodiment, the signal line 45 connected to the electrode 61 extends along the spoke portion 40. However, the wire extending along the spoke portion is not limited to a signal line.

[0058] In the above embodiment, the occupant's physique and posture are detected by the camera 14, but the configuration of the detection unit is not limited to that described above. The detection unit may detect the occupant's physique or posture. For example, one or more seating sensors may be provided on the seating surface of the seat cushion and / or seat back, and the occupant's physique or posture may be detected based on the signals from the seating sensors. Therefore, the threshold setting unit 51 may set a threshold Ca according to the occupant's physique or posture. When the position of the steering wheel 10 is adjusted by the telescopic mechanism 12 and the tilt mechanism 13, the positional relationship between the occupant and the steering wheel 10 may remain constant regardless of the occupant's physique. Therefore, the detection unit (e.g., camera 14) may detect the degree of proximity between the steering wheel 10 and the occupant PS's body (e.g., lower limbs), and the threshold setting unit 51 may set a threshold Ca according to the detection result.

[0059] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other. [Explanation of Symbols]

[0060] 10 Steering wheel, 11 Steering shaft, 14 Camera, 20 Hub section, 30 Rim section, 31 Core metal, 32 Base material, 33 Surface layer, 36 Locking section, 45 Signal line, 50 Controller, 51 Threshold setting section, 52 Judgment section, 60 Sensor section, 61 Electrode, 63 Adhesive, 100 Steering device, 611 Inner electrode layer, 612 Outer electrode layer, 613 Insulating layer, AR1 Inner diameter side region, AR3 Front side region, Ca Threshold

Claims

1. The hub section connected to the steering shaft, The rim portion extends around the hub portion along a closed curve of a predetermined shape, over the entire circumference of the hub portion, and is gripped by the occupant. A steering device for a vehicle comprising a spoke portion connecting the hub portion and the rim portion, The system further comprises a capacitive sensor unit having electrodes provided on the rim portion to detect the gripping motion of the rim portion by the occupant, The rim portion comprises a skeletal portion that forms the framework of the rim portion and a skin portion that covers the rim portion over its entire circumference in the circumferential direction. A steering device characterized in that, when the rim portion is cut perpendicular to the closed curve, the region on the hub portion side of the cross-section of the rim portion is defined as the inner diameter region, and the region opposite the inner diameter region is defined as the outer diameter region, the electrode is located between the skeletal portion and the skin portion and extends in the circumferential direction in the inner diameter region.

2. In the steering device according to claim 1, The steering device is characterized in that the electrode is provided extending circumferentially in the region on the base end side of the steering shaft, within the inner diameter side region of the cut surface of the rim portion.

3. In the steering device according to claim 1 or 2, The rim portion further has a base portion that surrounds the skeletal portion around its entire circumference, The steering device is characterized in that the electrode comprises a first electrode layer mounted on the surface of the base, a second electrode layer positioned facing the skin portion and opposite to the first electrode layer, and an insulating layer interposed between the first electrode layer and the second electrode layer.

4. In the steering device according to claim 3, A steering device further comprising an adhesive portion provided on the surface of the base portion for bonding the first electrode layer.

5. In the steering device according to claim 3, The steering device is characterized in that the base portion has a concave locking portion that locks the circumferential end of the electrode.

6. In the steering device according to claim 1 or 2, The steering device is characterized in that the sensor portion further has a wire whose one end is electrically connected to the electrode and extends along the spoke portion.

7. In the steering device according to claim 1 or 2, A detection unit for detecting the occupant's physique and / or posture, A determination unit determines whether the rim portion is gripped based on the magnitude of the capacitance detected via the electrode and the threshold value, A steering device further comprising a threshold setting unit that sets the threshold according to the occupant's physique and / or posture detected by the detection unit.

8. In the steering device according to claim 1 or 2, The electrode is a plurality of electrodes arranged in the rim portion, divided into a plurality in the circumferential direction. A steering device further comprising gripping area identification, which identifies the gripping area of ​​the rim portion by the occupant in response to signals from the plurality of electrodes.

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