Steering device

Abstract

To appropriately detect gripping of a steering handle.SOLUTION: A steering device includes: a steering handle; and a sensor unit 62L1 configured to detect a contact or an adjacency of a human body to the steering handle. The sensor unit 62L1 includes: an electrode 60L1 disposed on the steering handle; a measurement unit 68 configured to measure capacitance of the electrode 60L1; and a switch element SW1 configured to switch between a first state in which the electrode 60L1 is grounded and a second state in which the electrode 60L1 is not grounded.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a steering device that detects whether it is being gripped by an occupant. [Background technology]

[0002] One known example of this type of device is one that detects whether the steering wheel is being gripped based on changes in capacitance (see, for example, Patent Document 1). Patent Document 1 discloses a technique for reducing electromagnetic noise by slowing down the operating speed of an FET that switches between supplying and cutting off power to a heater wire, thereby reducing electromagnetic noise that affects the output of a capacitance sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-32036 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional techniques, it is difficult to avoid the influence of electromagnetic noise generated separately from the heater wire simply by temporarily stopping the power supply to the heater wire when detecting a change in capacitance. The present invention reduces the effects of electromagnetic noise and properly detects whether a driver is gripping the steering wheel, leading to improved traffic safety and contributing to the development of sustainable transportation systems. [Means for solving the problem]

[0005] One aspect of the present invention is a steering device comprising a steering wheel and a sensor unit that detects contact or proximity of a human body with the steering wheel, wherein the sensor unit includes an electrode provided on the steering wheel, a measuring unit that measures the capacitance of the electrode, and a switch element that switches between a first state in which the electrode is grounded and a second state in which the electrode is not grounded. The sensor unit further includes a control unit that controls switching of the switch element and a capacitive element. The second state includes a third state in which a voltage from a predetermined power supply is applied to the electrode via the switch element and a fourth state in which the electrode is connected to the capacitive element via the switch element. When switching from the third state to the fourth state or from the fourth state to the third state based on a control signal from the control unit, the switch element first switches to the first state and then switches to the fourth state or the third state, and charge on the electrode is accumulated in the third state, transferred to the capacitive element in the fourth state, and discharged to the ground line in the first state. [Effects of the Invention]

[0006] According to the present invention, it is possible to appropriately detect whether the steering wheel is being gripped. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating the configuration of a steering device and a safe driving support system including the steering device according to an embodiment of the invention; [Figure 2] FIG. 4 is a schematic diagram illustrating a grip detection range by an electrode. [Figure 3] FIG. 2 is a diagram illustrating an example of a circuit configuration of a sensor unit. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <System configuration> FIG. 1 is a diagram illustrating the configuration of a steering device 1 according to an embodiment and a safe driving support system 9 including the steering device 1. As shown in FIG.

[0009] The safe driving support system 9 includes a steering device 1 mounted on a vehicle (not shown) and a control device group 8 communicatively connected to the steering device 1, and uses the steering device 1 and the control device group 8 to support the driver in safe driving of the vehicle.

[0010] In the embodiment, each of the devices 81 to 84 constituting the control device group 8 is described as an in-vehicle device capable of communicating with the steering device 1, for example, by CAN communication via a CAN (Controller Area Network) bus 80, but all or some of the multiple devices 81 to 84 constituting the control device group 8 may be configured as an off-vehicle device capable of wireless communication with the steering device 1 via an in-vehicle communication device not shown.

[0011] <Outline of the steering system> The steering device 1 includes a steering wheel 2 that accepts the driver's steering operation of the vehicle and auxiliary operation of vehicle auxiliary equipment, a steering shaft 3 that supports the steering wheel 2, and a grip detection device 6 that detects the driver's grip on the steering wheel 2. The auxiliary operation includes operations for a navigation system, an audio system, an air conditioning system, a multi-information display, etc., as well as operations for a driving assistance system. The driving assistance system includes, for example, a Lane Keep Assist System (LKAS) and an Adaptive Cruise Control (ACC).

[0012] The steering wheel 2 comprises a rim portion 20, which is, for example, circular and can be gripped by the driver, a hub portion 23 provided inside the rim portion 20, and three spoke portions 25L, 25R, 25D extending radially from the hub portion 23 and connected to the rim inner peripheral portion 21 of the rim portion 20.

[0013] The hub portion 23 is disk-shaped and is provided, for example, at the center of the rim portion 20 as viewed from the driver's seat, and constitutes the center of the steering wheel 2. A steering shaft 3 that axially supports the steering wheel 2 is connected to the back side of the hub portion 23 as viewed from the driver's seat. The steering shaft 3 is an axial connecting member that connects a core metal that is the framework of the hub portion 23 with a steering mechanism that constitutes part of the vehicle body (not shown). Therefore, the steering torque generated when the driver rotates the steering wheel 2 is transmitted to the steering mechanism by this steering shaft 3.

[0014] The rim portion 20 and hub portion 23 are connected by three spokes 25L, 25R, and 25D. The left spoke 25L extends horizontally and connects the left portion of the hub portion 23 as viewed from the driver's seat to left spoke connection portion 26L, which is the left portion of the rim inner periphery 21 as viewed from the driver's seat. The right spoke 25R extends horizontally and parallel to the left spoke 25L and connects the right portion of the hub portion 23 as viewed from the driver's seat to right spoke connection portion 26R, which is the right portion of the rim inner periphery 21 as viewed from the driver's seat. The lower spoke 25D extends vertically and perpendicular to the spokes 25L and 25R and connects the lower portion of the hub portion 23 as viewed from the driver's seat to the lower portion of the rim inner periphery 21 as viewed from the driver's seat.

[0015] 1, a left thumb locking portion 27L that is concave radially outward when viewed from the driver's seat is formed at the part of rim inner circumferential portion 21 that connects to the upper part of left spoke connection portion 26L when viewed from the front from the driver's seat. Also, a right thumb locking portion 27R that is concave radially outward when viewed from the front from the driver's seat is formed at the part of rim inner circumferential portion 21 that connects to the upper part of right spoke connection portion 26R when viewed from the front from the driver's seat.

[0016] In the steering device 1 according to the embodiment, the recommended gripping position for the driver's left hand is when the thumb of the left hand is engaged with the left thumb engagement portion 27L, the base of the thumb is in contact with the left spoke connection portion 26L, and the remaining fingers of the left hand grip the rim portion 20. Therefore, the recommended gripping position for the driver's left hand is determined to be the portion of the rim portion 20 that includes the left spoke connection portion 26L.

[0017] Furthermore, in the steering device 1 according to the embodiment, the recommended gripping position for the driver's right hand is when the thumb of the right hand is engaged with the right thumb engagement portion 27R, the base of the thumb is in contact with the right spoke connection portion 26R, and the remaining fingers of the right hand grip the rim portion 20. Therefore, the recommended gripping position for the driver's right hand is determined to be the portion of the rim portion 20 that includes the right spoke connection portion 26R.

[0018] The left spoke portion 25L and the right spoke portion 25R are provided with a left accessory operation console unit 5L and a right accessory operation console unit 5R, respectively, that accept operation commands for the driver to operate vehicle accessories (not shown). The left accessory operation console unit 5L and the right accessory operation console unit 5R each have a substantially rectangular shape when viewed from the driver. The driver can operate the vehicle accessories by operating multiple switches provided on the left accessory operation console unit 5L and the right accessory operation console unit 5R with their fingers. The left accessory operation console unit 5L and the right accessory operation console unit 5R may also be called the left function switch unit and the right function switch unit, respectively.

[0019] In the following description, the positions of the approximately circular rim portion 20, rim inner periphery 21, hub portion 23, and steering shaft 3 as viewed from the driver, and the orientations of each spoke portion 25L, 25R, and 25D may also be expressed in degrees clockwise around the steering shaft 3 and based on the position of the top end 20C of the rim portion 20 as viewed from the front from the driver's seat. That is, the right spoke portion 25R extends along an angle of 90 degrees, connecting the hub portion 23 and the 90-degree portion of the rim inner periphery 21. The lower spoke portion 25D extends along an angle of 180 degrees, connecting the hub portion 23 and the 180-degree portion of the rim inner periphery 21. The left spoke portion 25L extends along an angle of 270 degrees, connecting the hub portion 23 and the 270-degree portion of the rim inner periphery 21. Expressed in terms of the clockwise angle [deg], the recommended grip position for the driver's left hand is set to a position of 270 deg on the rim portion 20. The recommended grip position for the driver's right hand is set to a position of 90 deg on the rim portion 20.

[0020] <Grip detection device> The grip detection device 6 includes, for example, an electrode 60 provided on the steering wheel 2 and a sensor unit 62 electrically connected to the electrode 60. Hereinafter, the first left electrode 60L1 and the second left electrode 60L2, and the first right electrode 60R1 and the second right electrode 60R2 may be collectively referred to as electrodes 60.

[0021] Each of the four electrodes 60L1, 60L2, 60R1, and 60R2 is formed in a conductive plate shape. The first left electrode 60L1 and the second left electrode 60L2 are provided on the steering wheel 2 near a recommended gripping position for the left hand relative to the rim portion 20. More specifically, the first left electrode 60L1 is provided on the left spoke portion 25L as viewed from the driver, along an upper and radially outer sidewall surface of the left accessory operation console unit 5L (more specifically, along an end surface of a printed wiring board (which may also be called an electronic board) (not shown) arranged in the left accessory operation console unit 5L). The second left electrode 60L2 is provided on the left spoke portion 25L as viewed from the driver, below the left accessory operation console unit 5L (more specifically, along an end surface of the printed wiring board) and along a surface of the lower left part of the hub portion 23 facing the rim portion 20.

[0022] Similarly, the first right electrode 60R1 and the second right electrode 60R2 are provided on the steering wheel 2 near a recommended gripping position with the right hand determined with respect to the rim portion 20. More specifically, the first right electrode 60R1 is provided on the right spoke portion 25R as viewed from the driver, along an upper and radially outer side wall surface of the right accessory operation console unit 5R (more specifically, along an end surface of a printed wiring board disposed in the right accessory operation console unit 5R). The second right electrode 60R2 is provided on the right spoke portion 25R as viewed from the driver, below the right accessory operation console unit 5R (more specifically, along an end surface of the printed wiring board) and along a surface of the lower right part of the hub portion 23 that faces the rim portion 20.

[0023] <Sensor unit> The sensor unit 62 includes four sensor units 62L1, 62L2, 62R1, and 62R2 corresponding to the four electrodes 60L1, 60L2, 60R1, and 60R2. The sensor unit 62L1 is connected to the first left electrode 60L1 via a left wiring 61L1. The sensor unit 62L2 is connected to the second left electrode 60L2 via a left wiring 61L2.

[0024] The sensor unit 62R1 is connected to the first right electrode 60R1 via a right wiring 61R1, and the sensor unit 62R2 is connected to the second right electrode 60R2 via a right wiring 61R2. The sensor units 62L1 and 62L2 are provided, for example, inside the left spoke portion 25L together with the above-mentioned left accessory operation console unit 5L. The sensor units 62R1 and 62R2 are provided inside the right spoke portion 25R together with the above-mentioned right accessory operation console unit 5R.

[0025] <Grip detection range> 2 is a schematic diagram illustrating grip detection ranges RL1, RL2, RR1, and RR2 defined by the electrodes 60 (60L1, 60L2, 60R1, and 60R2) described above. When a predetermined voltage is applied to the corresponding electrodes 60L1, 60L2, 60R1, and 60R2, electric field lines are induced in the respective grip detection ranges RL1, RL2, RR1, and RR2 from these electrodes 60L1, 60L2, 60R1, and 60R2.

[0026] In this embodiment, as described above, the first left electrode 60L1 is provided on the left spoke portion 25L near the recommended gripping position (270 degrees) of the rim portion 20 for the left hand, and the second left electrode 60L2 is provided on the hub portion 23 near the recommended gripping position (270 to 180 degrees) of the rim portion 20 for the left hand. With this configuration, the grip detection ranges RL1 and RL2 correspond to the ranges of 210° to 260° and 260° to 330°, respectively, centered on the recommended grip position of the rim portion 20 for the left hand.

[0027] Similarly, the first right electrode 60R1 is provided on the right spoke portion 25R near the recommended gripping position (90 degrees) of the rim portion 20 for the right hand, and the second right electrode 60R2 is provided on the hub portion 23 near the recommended gripping position (90 to 180 degrees) of the rim portion 20 for the right hand. With this configuration, the grip detection ranges RR1 and RR2 correspond to the ranges of 100 to 150 degrees and 30 to 100 degrees, respectively, centered on the recommended grip position of the rim portion 20 for the right hand.

[0028] <Circuit configuration example> 3 is a diagram illustrating an example of the circuit configuration of the sensor unit 62L1 of the grip detection device 6. Although not shown, the circuit configurations of the other sensor units 62L2, 62R1, and 62R2 other than the sensor unit 62L1 are similar. The sensor unit 62L1 measures the electrical characteristics of the left electrode 60L1 (e.g., the capacitance between the left electrode 60L1 and ground (e.g., the vehicle body)), and based on the measurement results, detects the driver's grip on the steering wheel 2, and further estimates the driver's grip position on the rim portion 20.

[0029] The sensor unit 62L1 includes a first switch SW1, a pulse power supply 63, an amplifier 64, a control unit 67, a second switch SW2, a charging capacitor 65, a measuring unit 68, and a detection unit 69, and uses these to detect the driver's grip on the steering wheel 2. In Figure 3, the capacitance between the first left electrode 60L1 and ground is shown divided into a capacitance Ch formed by the human body H, including the driver's hands operating the steering wheel 2, and a floating capacitance Ce formed by floating capacitors E, such as wiring and components, excluding the human body H.

[0030] As shown in Fig. 3, the pulse power supply 63 and the amplifier 64 are connected in series. Furthermore, the second switch SW2 and the charging capacitor 65 are connected in parallel. The series circuit consisting of the pulse power supply 63 and the amplifier 64 and the parallel circuit consisting of the second switch SW2 and the charging capacitor 65 are connected via the first switch SW1. More specifically, the output terminal of the amplifier 64 and the first left electrode 60L1 are connected via the first switch SW1 and the left wiring 61L1. Furthermore, the second switch SW2 and the charging capacitor 65 are connected to the first left electrode 60L1 via the first switch SW1 and the left wiring 61L1.

[0031] The pulsed power supply 63 supplies a pulsed voltage Vs of a predetermined frequency and a predetermined voltage to the amplifier 64 in response to, for example, a command from the control unit 67. The amplifier 64 amplifies the pulsed voltage Vs supplied from the pulsed power supply 63 and applies it to the first left electrode 60L1 via the first switch SW1 and the left wiring 61L1.

[0032] The second switch SW2 is a switching element such as a transistor that is turned on / off by, for example, a drive circuit (not shown) in the control unit 67. For example, the control unit 67 turns off the second switch SW2 to accumulate (or charge) the charge capacitor 65 until the voltage VCref of the charge capacitor 65 reaches a predetermined voltage threshold Vthr. After the voltage VCref reaches the threshold Vthr, the control unit 67 further turns on the second switch SW2 to discharge the charge accumulated in the charge capacitor 65.

[0033] The first switch SW1 is a switching element that is switched by, for example, a drive circuit (not shown) in the control unit 67, and is configured by, for example, a field effect transistor (FET) etc. In the embodiment, the first switch SW1 has a terminal t1 for connecting the first left electrode 60L1 and the charging capacitor 65, a terminal t2 for connecting the first left electrode 60L1 and the amplifier 64, and a terminal t3 for connecting the first left electrode 60L1 and the ground line.

[0034] The ground line is at the same potential as the GND pattern of the PCB (Printed Circuit Board) on which the circuits of the sensor unit 62L1 except for the first left electrode 60L1 are formed, and is provided substantially parallel to at least one of the wiring patterns to the terminal t1 and the wiring patterns to the terminal t2. In Fig. 3, the ground line is illustrated parallel to the wiring pattern to the terminal t2. By placing the ground line (GND pattern) near the signal line (wiring pattern to terminal t2), the electromagnetic coupling between the signal line and the ground line is strengthened, making it possible to suppress coupling between the signal line and other patterns on the PCB. In other words, this prevents signals from other patterns on the PCB from being transmitted as noise to the signal line due to leakage currents and the like that flow along the PCB surface, and conversely, prevents signals from the signal line from being transmitted as noise to other patterns on the PCB.

[0035] The first switch SW1 is controlled by a command from the control unit 67 to switch the terminal t 2 As a result, the first left electrode 60L1 and the amplifier 64 are connected via the first switch SW1 and the left wiring 61L1, and a pulse voltage supplied from the pulse power supply 63 and the amplifier 64 is applied to the first left electrode 60L1, thereby charging the human body H and the floating capacitor E.

[0036] Subsequently, the first switch SW1 is controlled by the control unit 67 to turn on the terminal t 1 As a result, the first left electrode 60L1 and the charging capacitor 65 are connected via the first switch SW1 and the left wiring 61L1, and the charges stored in the human body H and the floating capacitor E are transferred to the charging capacitor 65, thereby charging the charging capacitor 65. As a result, the voltage VCref of the charging capacitor 65 rises.

[0037] In this way, when a pulse voltage is repeatedly applied to the first left electrode 60L1 by the pulse power supply 63 and the amplifier 64, the human body H and the floating capacitor E are alternately charged and discharged, and the voltage VCref of the charging capacitor 65 gradually increases. At this time, the time (which may be expressed as the number of pulses of the pulse power supply 63) until the voltage VCref of the charging capacitor 65 reaches a predetermined voltage threshold Vthr varies depending on the capacitance Ch formed by the human body H, i.e., the relative position of the driver's hand operating the steering wheel 2 with respect to the first left electrode 60L1. That is, when the driver's hand is gripping a portion of the rim portion 20 within the grip detection range RL1 (see FIG. 2) and the capacitance Ch is large, the time it takes for the voltage VCref of the charging capacitor 65 to reach the threshold Vthr is short. On the other hand, when the driver's hand is away from the grip detection range RL1 and the capacitance Ch is small, the time it takes for the voltage VCref of the charging capacitor 65 to reach the voltage threshold Vthr is long.

[0038] Furthermore, the first switch SW1 selects terminal t3 of the first switch SW1 at a predetermined timing in response to a command from the control unit 67. As a result, the first left electrode 60L1 and the ground line are connected via the first switch SW1 and the left wiring 61L1, and the charges stored in the human body H and the floating capacitor E and the charges remaining in the first left electrode 60L1 and the left wiring 61L1 are discharged to the ground line. For example, when selecting terminal t1 of the first switch SW1 described above and when selecting terminal t2 of the first switch SW1, the control unit 67 controls the switching of the first switch SW1 so that terminal t3 is first selected and then terminal t1 and terminal t2 are selected, respectively. In addition, the control unit 67 may control the switching of the first switch SW1 to select terminal t3 of the first switch SW1 in accordance with the timing at which the second switch SW2 is turned on (in other words, the charge stored in the charging capacitor 65 is discharged). Furthermore, the switching of the first switch SW1 may be controlled so as to select the terminal t3 of the first switch SW1 in accordance with the timing at which other accessories operate. The timing at which the terminal t3 of the first switch SW1 is selected can be changed as appropriate by a program executed by the control unit 67.

[0039] The measurement unit 68 measures the time and the number of pulses until the voltage VCref of the charging capacitor 65 reaches the threshold Vthr, and based on the measurement results, indirectly measures the capacitance Ch formed by the human body H present in the vicinity of the first left electrode 60L1. The measurement unit 68 transmits the measurement value Ch_d of the capacitance Ch obtained by the above procedure to the detection unit 69.

[0040] The detection unit 69 detects that the driver is gripping the rim portion 20 based on the capacitance measurement value Ch_d by the measurement unit 68, and when gripping of the rim portion 20 is detected, it estimates the gripping position on the rim portion 20. The larger the value of the capacitance measurement value Ch_d when gripping is detected, the more the detection unit 69 estimates that the driver is gripping a position on the rim portion 20 closer to the left spoke portion 25L (for example, 260 deg), and the smaller the value of the capacitance measurement value Ch_d when gripping is detected, the more the driver is gripping a position on the rim portion 20 farther from the left spoke portion 25L (for example, 210 deg).

[0041] As described above, the detection section 69 of the sensor unit 62L1 detects the driver's grip in the grip detection range RL1 of the rim section 20 based on the measurement value Ch_d of the capacitance Ch formed by the human body H present in the vicinity of the first left electrode 60L1, and estimates the grip position on the rim section 20. Although not explained further, the detection of gripping and estimation of gripping position in the grip detection range RL2 of the rim portion 20 by sensor unit 62L2, the detection of gripping and estimation of gripping position in the grip detection range RR1 of the rim portion 20 by sensor unit 62R1, and the detection of gripping and estimation of gripping position in the grip detection range RR2 of the rim portion 20 by sensor unit 62R2 are similar to the detection of gripping and estimation of gripping position in the grip detection range RL1 of the rim portion 20 by sensor unit 62L1 described above.

[0042] <Leak current countermeasures> Because the measurement of capacitance Ch using the sensor unit 62L1 described above involves handling minute signals, measures must be taken to prevent leakage currents from flowing along the surface of the PCB. A commonly known technique (also known as a guard ring) is to surround the circuit formed on the PCB with a shield pattern at the same potential as the signal line, thereby dispersing and mitigating the electric field that concentrates in specific parts of the circuit. While guard rings are effective in suppressing leakage currents, they have the disadvantage of increasing the external size of the PCB due to the need to surround the circuit with a shield pattern. In contrast, selecting terminal t3 of the first switch SW1 employed in this embodiment provides at least the same effect of suppressing leakage current as a guard ring. In other words, even without employing a guard ring, it is possible to suppress the accumulation of unnecessary charge in the left electrode 60L1 via leakage current flowing along the surface of the PCB and the generation of unnecessary charge in the charge transfer path from the left electrode 60L1 to the charging capacitor 65, thereby suppressing the influence of the human body H and the floating capacitor E on the measurement of the capacitance Ch. Furthermore, by eliminating the guard ring that surrounds the circuit, it is possible to reduce the size of the PCB and, as a result, improve the degree of freedom in the layout of components such as the left electrode 60L1.

[0043] According to the embodiment described above, the following effects can be obtained. (1) The steering device 1 includes a steering wheel 2 and a sensor unit 62 that detects contact or proximity of a human body with the steering wheel 2. The sensor unit 62L1 includes a left electrode 60L1 provided on the steering wheel 2, a measuring unit 68 that measures the capacitance Ch of the left electrode 60L1, and a first switch SW1 as a switching element that switches between a first state in which the left electrode 60L1 is grounded and a second state in which the left electrode 60L1 is not grounded. With this configuration, for example, unnecessary charge that accumulates in the left electrode 60L1 due to leakage current flowing along the PCB surface can be discharged by switching the first switch SW1 to the first state. On the other hand, when measuring the capacitance Ch of the human body H and the floating capacitor E, the first switch SW1 can be switched to the second state to move the charge accumulated in the left electrode 60L1 to the measuring unit 68. This makes it possible to properly detect whether the steering wheel 2 is being gripped.

[0044] (2) In the steering device 1 of (1) above, the sensor unit 62L1 further includes a control unit 67 that controls the switching of the first switch SW1 and a charging capacitor 65 as a capacitive element, and the second state includes a third state in which a voltage from a pulse power supply 63 as a predetermined power supply is applied to the left electrode 60L1 via the first switch SW1, and a fourth state in which the left electrode 60L1 is connected to the charging capacitor 65 via the first switch SW1, and the first switch SW1 switches between the first state, the third state as the second state, and the fourth state as the second state based on a control signal from the control unit 67. With this configuration, it is possible to switch between the three states, ie, the first state, the third state, and the fourth state, simply by switching the first switch SW1 based on a control signal from the control unit 67.

[0045] (3) In the steering device 1 described in (2) above, the charge in the left electrode 60L1 is accumulated in the third state, transferred to the charging capacitor 65 in the fourth state, and discharged to the ground line in the first state. With this configuration, it is possible to accumulate charge in the left electrode 60L1, transfer charge to the charging capacitor 65 on the measurement unit 68 side, and discharge unnecessary charge that accumulates in the left electrode 60L1 due to leakage current, etc., simply by switching the first switch SW1 based on a control signal from the control unit 67.

[0046] (4) In the steering device 1 of (3) above, for example, the sensor unit 62L1 has at least the first switch SW1, the charging capacitor 65, and the measuring unit 68 configured on a PCB as an electronic substrate, and at least one of the signal line patterns connecting the first switch SW1 and the left electrode 60L1, the first switch SW1 and the pulse power supply 63, and the first switch SW1 and the charging capacitor 65 is formed close to the ground line. With this configuration, selecting terminal t3 of the first switch SW1 (corresponding to the first state in which the left electrode 60L1 is grounded) provides an effect equivalent to that of a guard ring that suppresses leakage current. In other words, even without employing a guard ring, it is possible to suppress the accumulation of unnecessary charge in the left electrode 60L1 via leakage current or the like that flows along the surface of the PCB, and the generation of unnecessary charge in the charge transfer path from the left electrode 60L1 to the charging capacitor 65. This reduces the effects of the human body H and the floating capacitor E on the measurement of the capacitance Ch, thereby improving the measurement accuracy. In addition, by providing a ground line near the signal line pattern, line The electromagnetic coupling between the pattern and the ground line becomes stronger, line traces and other signals on the PCB line It is possible to prevent crosstalk between the patterns. Furthermore, by eliminating the guard ring that surrounds the circuit, it is possible to reduce the size of the PCB and, as a result, improve the degree of freedom in the layout of components such as the left electrode 60L1.

[0047] (5) In the steering device 1 of (1) above, the steering handle 2 comprises an annular rim portion 20, a hub portion 23 provided inside the rim portion 20, and spoke portions 25L, 25R, 25D extending radially from the hub portion 23 to the rim portion 20 and connecting the hub portion 23 to the inner peripheral portion of the rim portion 20, and for example, the sensor unit 62L1 (or the sensor unit 62R1) is arranged in the left accessory operation console unit (left-side function switch portion) 5L arranged in the spoke portion 25L (or the right accessory operation console unit (right-side function switch portion) 5R arranged in the right spoke portion 25R). Generally, it is easier to ensure a larger space within the spokes than within the rim, so by using the configuration described in (5) above, productivity can be improved compared to when the sensor unit is insert-molded into the steering wheel rim.

[0048] (6) In the steering device 1 of (5) above, the spoke portions 25L, 25R, 25D are provided in multiple numbers between the rim portion 20 and the hub portion 23 that are gripped by the occupant, and for example, the sensor units 62L1 and 62L2, 62R1 and 62R2 are respectively arranged on the left spoke portion 25L and the right spoke portion 25R of the multiple spoke portions 25L, 25R, 25D when viewed from the front from the driver's seat, and are also arranged close to switches and the like as components for performing at least one of vehicle information operations or driving assistance function operations within the left accessory operation console unit (left-side function switch portion) 5L and the right accessory operation console unit (right-side function switch portion) 5R. With this configuration, by placing the PCBs of sensor units 62L1 and 62L2, and 62R1 and 62R2 on the left accessory operation console unit (left-side function switch unit) 5L and the right accessory operation console unit (right-side function switch unit) 5R, which are arranged in pairs on the left and right spoke portions 25L and 25R, respectively, it becomes possible to properly detect gripping within the recommended gripping range on the left and right of the rim portion 20.

[0049] (7) In the steering device 1 of (6) above, the sensor unit 62 (62L1, 62L2, 62R1, 62R2) has at least the components other than the electrodes 60 (60L1, 60L2, 60R1, 60R2) on a PCB serving as an electronic substrate, and for example, the electrodes 60 of the sensor unit 62 arranged on the spoke portions 25L and 25R are provided in multiple numbers (60L1, 60L2, 60R1, 60R2) corresponding to the recommended gripping range, which is the predetermined gripping range of the left rim portion 20 and the right rim portion 20 of the steering wheel 2 when viewed from the front, and each is arranged along the end face of the PCB. This configuration makes it possible to appropriately arrange multiple electrodes 60 (60L1, 60L2, 60R1, 60R2) in the space (the edge surface around the PCB) created by, for example, eliminating the guard ring surrounding the circuits of the sensor units 62L1, 62L2, 62R1, 62R2 and reducing the size of the PCB.

[0050] The above embodiment can be modified in various ways, and modifications will be described below. (Variation 1) In the embodiment, an annular steering wheel is exemplified as the steering handle 2, but the present invention may also be applied to cases where a non-annular, rectangular, or rod-shaped steering handle is used.

[0051] (Variation 2) In the embodiment, four electrodes 60 are exemplified: a first left electrode 60L1, a second left electrode 60L2, a first right electrode 60R1, and a second right electrode 60R2, but the number of electrodes may be more or less than the four exemplified. Furthermore, four sensor units 62L1, 62L2, 62R1 and 62R2 are illustrated corresponding to the four electrodes 60L1, 60L2, 60R1 and 60R2, but the number of sensor units 62 may be increased or decreased depending on the number of electrodes 60. Furthermore, although the embodiment has been described with reference to a case where one sensor unit 62 corresponds to one electrode 60, multiple electrodes 60 may correspond to one sensor unit 62. For example, one sensor unit 62 arranged on the left spoke 25L in a front view corresponds to the first left electrode 60L1 and the second left electrode 60L2, and another sensor unit 62 arranged on the right spoke 25R in a front view corresponds to the first right electrode 60R1 and the second right electrode 60R2. Furthermore, the left and right sensor units 62 may be integrated into one, and in that case, the integrated sensor unit 62 may be placed in either the left spoke portion 25L, the right spoke portion 25R, or the lower spoke portion 25D.

[0052] The above description is merely an example, and the present invention is not limited to the above-described embodiment and modifications as long as the features of the present invention are not impaired. One or more of the above-described embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other. [Explanation of symbols]

[0053] 1 steering device, 2 steering handle, 5L left auxiliary operation console unit (function switch section), 5R right auxiliary operation console unit (function switch section), 6 grip detection device, 20 rim section, 23 hub section, 25L left spoke section, 25R right spoke section, 60 electrode, 60L1 first left electrode, 60L2 second left electrode, 60R1 first right electrode, 60R2 second right electrode, 61L1, 61L2 left wiring, 61R1, 61R2 right wiring, 62 (62L1, 62L2, 62R1, 62R2) sensor unit, 63 pulse power supply, 64 amplifier, 65 charging capacitor, 67 control section, 68 measurement section, 69 detection section, Ce stray capacitance, Ch electrostatic capacitance, H human body, RL1, RL2, RR1, RR2 grip detection range, SW1 1st switch, SW2 2nd switch

Claims

1. A steering device comprising a steering wheel and a sensor unit that detects contact or proximity of a human body with the steering wheel, The sensor unit includes: an electrode provided on the steering wheel; a measuring unit for measuring the capacitance of the electrode; a switch element that switches between a first state in which the electrode is grounded and a second state in which the electrode is not grounded, the sensor unit further includes a control unit that controls switching of the switch element and a capacitive element; the second state includes a third state in which a voltage from a predetermined power supply is applied to the electrode via the switch element, and a fourth state in which the electrode is connected to the capacitive element via the switch element; the switch element, when switching from the third state to the fourth state or from the fourth state to the third state based on a control signal from the control unit, first switches to the first state and then switches to the fourth state or the third state; The charge on the electrode is stored in the third state, transferred to the capacitive element in the fourth state, and discharged to a ground line in the first state. A steering device characterized by:

2. In the steering device according to claim 1, the predetermined power source is a pulse power source, the switching element switches to the third state in response to a rising edge of a pulse voltage applied from the pulse power supply, and switches to the fourth state in response to a falling edge of the pulse voltage; the measurement unit measures the capacitance of the electrode based on a time required for the voltage of the capacitive element to reach a predetermined threshold value or the number of pulses of the pulse voltage required for the voltage of the capacitive element to reach the predetermined threshold value. A steering device characterized by:

3. In the steering device described in claim 1, the sensor unit is configured such that at least the switch element, the capacitive element, and the measurement unit are arranged on an electronic substrate; At least one of the signal line patterns connecting the switch element and the electrode, the switch element and the predetermined power supply, and the switch element and the capacitive element is formed in the vicinity of the ground line. A steering device characterized by:

4. In the steering device described in claim 1, the steering wheel includes an annular rim portion, a hub portion provided inside the rim portion, and spoke portions extending from the hub portion in a radial direction of the rim portion and connecting the hub portion and an inner peripheral portion of the rim portion, The sensor unit is disposed in a function switch portion disposed in the spoke portion. A steering device characterized by:

5. In the steering device according to claim 4, the spoke portion is provided in plurality between the rim portion and the hub portion, which are gripped by a rider; The sensor units are disposed in the left and right spoke portions of the plurality of spoke portions as viewed from the front of the driver's seat, and are disposed in the vicinity of components for performing at least one of vehicle information operation and driving assistance function operation within the function switch portion. A steering device characterized by:

6. In the steering device according to claim 5, the sensor unit has at least a configuration other than the electrodes on an electronic substrate; a plurality of the electrodes are provided corresponding to predetermined gripping ranges of the left and right rim portions of the steering wheel when viewed from the front, and each of the electrodes is arranged along an end surface of the electronic board; A steering device characterized by:

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