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 a steering wheel is being gripped by an occupant.

Background Art

[0002] As this type of device, a device that detects whether a steering wheel is being gripped based on a change in capacitance is known (see, for example, Patent Document 1). Patent Document 1 discloses a technique for reducing electromagnetic noise that affects the output of a capacitance sensor by delaying the operating speed of an FET that switches the supply and cut-off of power to a heater wire as a countermeasure against electromagnetic noise.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, it is difficult to avoid the influence of electromagnetic noise generated separately from the heater wire only by temporarily stopping the power supply to the heater wire when detecting a change in capacitance. The present invention can suppress the influence of electromagnetic noise and appropriately detect the gripping of the steering wheel by the driver, leading to an improvement in traffic safety. As a result, it can contribute to the development of a sustainable transportation system.

Means for Solving the Problems

[0005] One aspect of the present invention is a steering device including a steering wheel and a sensor unit that detects contact or proximity of a human body to the steering wheel, wherein the sensor unit includes an electrode provided on the steering wheel, a measurement 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.

Advantages of the Invention

[0006] According to the present invention, it becomes possible to appropriately detect the gripping of the steering wheel.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the 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 safety driving support system 9 including the steering device 1.

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

[0010] In the embodiment, each of the devices 81 to 84 constituting the control device group 8 will be described as an in-vehicle device capable of communicating with the steering device 1 by CAN communication via, for example, a CAN (Controller Area Network) bus 80. However, all or part of the plurality of 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] <Overview of Steering Device> The steering device 1 includes a steering wheel 2 that receives a steering operation of the vehicle by the driver, an auxiliary machine operation for an auxiliary machine, etc., a steering shaft 3 that pivotally supports the steering wheel 2, and a gripping detection device 6 that detects the gripping of the steering wheel 2 by the driver. The auxiliary machine operation, etc. includes operations for a navigation device, an audio device, an air conditioner, a multi-information display, etc., and operations for a driving support device. The driving support device includes, for example, LKAS (Lane Keep Assistant System) and ACC (Adaptive Cruise Control).

[0012] The steering wheel 2 is, for example, annular and includes a rim portion 20 that can be gripped by the driver, a hub portion 23 provided inside the rim portion 20, and three spoke portions 25L, 25R, 25D that extend along the radial direction from the hub portion 23 and are connected to the inner peripheral portion 21 of the rim 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. On the back side of the hub portion 23 as viewed from the driver's seat, a steering shaft 3 that pivotally supports the steering wheel 2 is connected. The steering shaft 3 is a shaft-like connecting member that connects a core bar that is the skeleton of the hub portion 23 and a steering mechanism that constitutes a part of the vehicle body (not shown). Therefore, the steering torque generated when the driver rotates the steering wheel 2 is transmitted to the above-described steering mechanism by this steering shaft 3.

[0014] The rim portion 20 and the hub portion 23 are connected by three spoke portions 25L, 25R, and 25D. The left spoke portion 25L extends along the horizontal direction and connects a left portion of the hub portion 23 as viewed from the front in the driver's seat and a left spoke connection portion 26L which is a left portion of the inner peripheral portion 21 of the rim as viewed from the front in the driver's seat. The right spoke portion 25R extends parallel to the left spoke portion 25L and along the horizontal direction, and connects a right portion of the hub portion 23 as viewed from the front in the driver's seat and a right spoke connection portion 26R which is a right portion of the inner peripheral portion 21 of the rim as viewed from the front in the driver's seat. The lower spoke portion 25D extends orthogonally to each of the spoke portions 25L and 25R and along the vertical direction, and connects a lower portion of the hub portion 23 as viewed from the front in the driver's seat and a lower portion of the inner peripheral portion 21 of the rim as viewed from the front in the driver's seat.

[0015] As shown in FIG. 1, in a portion of the inner peripheral portion 21 of the rim that is connected to an upper portion of the left spoke connection portion 26L as viewed from the front in the driver's seat, a left thumb locking portion 27L that is concave outward in the radial direction as viewed from the front in the driver's seat is formed. Further, in a portion of the inner peripheral portion 21 of the rim that is connected to an upper portion of the right spoke connection portion 26R as viewed from the front in the driver's seat, a right thumb locking portion 27R that is concave outward in the radial direction as viewed from the front in the driver's seat is formed.

[0016] In the steering device 1 according to the embodiment, a posture in which the driver's left hand holds the rim portion 20 with the remaining fingers of the left hand while locking the left thumb to the left thumb locking portion 27L and bringing the base of the left thumb into contact with the left spoke connection portion 26L is defined as a recommended gripping posture for the driver's left hand. Therefore, the recommended gripping position for the driver's left hand is defined in a portion of the rim portion 20 that includes the left spoke connection portion 26L.

[0017] In addition, in the steering device 1 according to the embodiment, with the right thumb locked to the right thumb locking portion 27R and the base of the right thumb in contact with the right spoke connection portion 26R, the posture of gripping the rim portion 20 with the remaining fingers of the right hand is defined as the recommended gripping posture for the driver's right hand. Therefore, the recommended gripping position for the driver's right hand is determined at a portion of the rim portion 20 that includes the right spoke connection portion 26R.

[0018] On the left spoke portion 25L and the right spoke portion 25R, a left auxiliary operation console unit 5L and a right auxiliary operation console unit 5R for receiving auxiliary operations for the driver to operate vehicle accessories (not shown) and the like are provided, respectively. These left auxiliary operation console unit 5L and right auxiliary operation console unit 5R are substantially rectangular in shape when viewed from the driver. The driver can operate vehicle accessories and the like by operating a plurality of switches provided on the left auxiliary operation console unit 5L and the right auxiliary operation console unit 5R with fingers. Note that the left auxiliary operation console unit 5L and the right auxiliary operation console unit 5R may be referred to as a left function switch portion and a right function switch portion, respectively.

[0019] Also, in the following description, the positions of the substantially circular rim portion 20, the inner peripheral portion 21 of the rim, the hub portion 23, and the steering shaft 3, and the directions of the respective spoke portions 25L, 25R, 25D are sometimes represented by clockwise angles [deg] centered on the steering shaft 3 and with reference to the position of the upper end portion 20C of the rim portion 20 in a front view from the driver's seat. That is, the right spoke portion 25R extends along the 90 deg direction and connects the 90 deg portions of the hub portion 23 and the inner peripheral portion 21 of the rim. The lower spoke portion 25D extends along the 180 deg direction and connects the 180 deg portions of the hub portion 23 and the inner peripheral portion 21 of the rim. Also, the left spoke portion 25L extends along the 270 deg direction and connects the 270 deg portions of the hub portion 23 and the inner peripheral portion 21 of the rim. When represented by the above clockwise angle [deg], the recommended gripping position for the driver's left hand is determined at the 270 deg position of the rim portion 20. Also, the recommended gripping position for the driver's right hand is determined at the 90 deg position of the rim portion 20.

[0020] <Grip detection device> The grip detection device 6 includes, as an 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 the electrode 60.

[0021] The four electrodes 60L1, 60L2, 60R1, and 60R2 are each configured in a plate shape having conductivity. The first left electrode 60L1 and the second left electrode 60L2 are provided in the vicinity of the recommended gripping position by the left hand defined for the rim portion 20 of the steering wheel 2. More specifically, the first left electrode 60L1 is provided along the upper and radially outer side wall surface (more specifically, the end face of a printed wiring board (which may be called an electronic substrate) disposed within the left auxiliary machine operation console unit 5L) in the left spoke portion 25L as viewed from the driver. Also, the second left electrode 60L2 is provided along the lower side (more specifically, the end face of the printed wiring board) of the left auxiliary machine operation console unit 5L and the surface facing the rim portion 20 at the lower left portion of the hub portion 23 in the left spoke portion 25L as viewed from the driver.

[0022] Similarly, the first right electrode 60R1 and the second right electrode 60R2 are provided in the vicinity of the recommended gripping position by the right hand defined for the rim portion 20 of the steering wheel 2. More specifically, the first right electrode 60R1 is provided along the upper and radially outer side wall surface (more specifically, the end face of a printed wiring board disposed within the right auxiliary machine operation console unit 5R) in the right spoke portion 25R as viewed from the driver. Also, the second right electrode 60R2 is provided along the lower side (more specifically, the end face of the printed wiring board) of the right auxiliary machine operation console unit 5R and the surface facing the rim portion 20 at the lower right portion of the hub portion 23 in the right spoke portion 25R as viewed from the driver.

[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 the left wiring 61L1. The sensor unit 62L2 is connected to the second left electrode 60L2 via the left wiring 61L2.

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

[0025] <Grip detection range> FIG. 2 is a schematic diagram illustrating grip detection ranges RL1, RL2, RR1, and RR2 by the electrodes 60 (60L1, 60L2, 60R1, and 60R2) as described above. In each of the grip detection ranges RL1, RL2, RR1, and RR2, by applying a predetermined voltage to the corresponding electrodes 60L1, 60L2, 60R1, and 60R2, electric lines of force are induced from these electrodes 60L1, 60L2, 60R1, and 60R2.

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

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

[0028] <Circuit configuration example> FIG. 3 is a diagram illustrating the circuit configuration of the sensor unit 62L1 among the gripping detection devices 6. Although illustration is omitted, the same applies to the circuit configurations of the other sensor units 62L2, 62R1, and 62R2 other than the sensor unit 62L1. The sensor unit 62L1 measures the electrical characteristics (for example, the capacitance between the left electrode 60L1 and the ground (for example, the vehicle body)), detects the gripping of the steering wheel 2 by the driver based on this measurement result, and further estimates the gripping position by the driver 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 measurement unit 68, and a detection unit 69, and detects the gripping of the steering wheel 2 by the driver by using these components. In FIG. 3, the capacitance between the first left electrode 60L1 and the ground is shown divided into the capacitance Ch formed by the human body H including the hand of the driver operating the steering wheel 2 and the stray capacitance Ce formed by the stray 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. Also, the second switch SW2 and the charging capacitor 65 are connected in parallel. The series circuit composed of the pulse power supply 63 and the amplifier 64 and the parallel circuit composed 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. Also, the second switch SW2 and the charging capacitor 65 and the first left electrode 60L1 are connected via the first switch SW1 and the left wiring 61L1.

[0031] The pulse power supply 63 supplies a pulse voltage Vs of a predetermined frequency and a predetermined voltage to the amplifier 64 in response to a command from the control unit 67, for example. The amplifier 64 amplifies the pulse voltage Vs supplied from the pulse 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 a drive circuit (not shown) in the control unit 67, for example. The control unit 67, as an example, turns off the second switch SW2 to accumulate (which may be called charging) charge in the charging capacitor 65 until the voltage VCref of the charging capacitor 65 reaches a threshold voltage Vthr of a predetermined voltage. The control unit 67 further turns on the second switch SW2 after the voltage VCref reaches the threshold voltage Vthr to discharge the charge stored in the charging capacitor 65.

[0033] The first switch SW1 is a switching element that is switched and controlled by a drive circuit (not shown) in the control unit 67, for example, and is composed of, for example, an FET (Field effect transistor) or the like. In the embodiment, it 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 circuit excluding the first left electrode 60L1 among the circuits of the sensor unit 62L1 is formed, and is provided substantially parallel to at least one of the wiring pattern to the terminal t1 and the wiring pattern to the terminal t2. In FIG. 3, the ground line is illustrated in parallel with the wiring pattern to the terminal t2. By arranging the ground line (GND pattern) near the signal line (the wiring pattern to the terminal t2), it is possible to strengthen the electromagnetic coupling between the signal line and the ground line and suppress the coupling between the signal line and other patterns on the PCB. In other words, it suppresses the transmission of signals of other patterns on the PCB to the signal line as noise due to leakage current or the like passing through the PCB surface, and conversely, suppresses the transmission of the signal of the signal line to other patterns on the PCB as noise.

[0035] The first switch SW1 selects the terminal t1 of the first switch SW1 in response to the rising edge of the pulse voltage Vs of the pulse power supply 63 according to a command from the control unit 67. Thereby, the first left electrode 60L1 and the amplifier 64 are connected via the first switch SW1 and the left wiring 61L1, and the pulse voltage supplied from the pulse power supply 63 and the amplifier 64 is applied to the first left electrode 60L1, and the human body H and the floating capacitor E are charged.

[0036] Subsequently, the first switch SW1 selects the terminal t2 of the first switch SW1 in response to the falling edge of the pulse voltage Vs of the pulse power supply 63 according to a command from the control unit 67. Thereby, the first left electrode 60L1 and the charging capacitor 65 are connected via the first switch SW1 and the left wiring 61L1, and the charge charged in the human body H and the floating capacitor E is moved to the charging capacitor 65 to charge the charging capacitor 65. Thereby, the voltage VCref of the charging capacitor 65 rises.

[0037] Thus, when a pulsed voltage is repeatedly applied to the first left electrode 60L1 by the pulse power supply 63 and the amplifier 64, charging and discharging of the human body H and the floating capacitor E are alternately repeated, and the voltage VCref of the charging capacitor 65 gradually increases. At this time, the time (which may also be represented by 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 according to the capacitance Ch formed by the human body H, that is, 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 grips a portion within the grip detection range RL1 (see FIG. 2) of the rim portion 20 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. 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 the terminal t3 of the first switch SW1 at a predetermined timing according to a command from the control unit 67. Thereby, the first left electrode 60L1 and the ground line are connected via the first switch SW1 and the left wiring 61L1, and the charges charged 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. The control unit 67 controls the switching of the first switch SW1 such that when, for example, selecting the terminal t1 of the first switch SW1 described above and when selecting the terminal t2 of the first switch SW1, the terminal t3 is selected once and then the terminals t1 and t2 are selected. Also, the control unit 67 may control the switching of the first switch SW1 to select the terminal t3 of the first switch SW1 in accordance with the timing of turning on the second switch SW2 (in other words, discharging the charges stored in the charging capacitor 65). Furthermore, the switching of the first switch SW1 may be controlled to select the terminal t3 of the first switch SW1 in accordance with the timing when other auxiliary devices operate, etc. The timing for selecting the terminal t3 of the first switch SW1 is configured to be appropriately changeable by the program executed by the control unit 67.

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

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

[0041] As described above, the detection unit 69 of the sensor unit 62L1 detects the gripping by the driver in the gripping detection range RL1 of the rim portion 20 and estimates the gripping position on the rim portion 20 based on the measured value Ch_d of the capacitance Ch formed by the human body H existing in the vicinity of the first left electrode 60L1. Although the description is omitted, the detection of the gripping and the estimation of the gripping position in the gripping detection range RL2 of the rim portion 20 by the sensor unit 62L2, the detection of the gripping and the estimation of the gripping position in the gripping detection range RR1 of the rim portion 20 by the sensor unit 62R1, and the detection of the gripping and the estimation of the gripping position in the gripping detection range RR2 of the rim portion 20 by the sensor unit 62R2 are the same as the detection of the gripping and the estimation of the gripping position in the gripping detection range RL1 of the rim portion 20 by the above-described sensor unit 62L1.

[0042] <Countermeasures against leakage current> Since the measurement of the capacitance Ch by the sensor unit 62L1 described above deals with minute signals, countermeasures against leakage current flowing on the surface of the PCB are required. Generally, a method (also called guard ring) is known in which the periphery of a circuit formed on a PCB is surrounded by a shield pattern at the same potential as the signal line to disperse and relax the electric field concentrated on a specific part of the circuit. While the guard ring can suppress leakage current, there is a drawback in that the outer size of the PCB increases because it is necessary to surround the circuit with a shield pattern. On the other hand, when the terminal t3 of the first switch SW1 adopted in the present embodiment is selected, an effect of suppressing at least the same leakage current as that of the guard ring can be obtained. That is, even without adopting a guard ring, it is possible to suppress unnecessary charges from accumulating on the left electrode 60L1 via leakage current or the like flowing on the surface of the PCB, or unnecessary charges from being generated in the charge transfer path from the left electrode 60L1 to the charging capacitor 65. Therefore, it is possible to suppress the influence on the measurement of the capacitance Ch of the human body H and the stray capacitor E. In addition, by abolishing the guard ring surrounding the periphery of the circuit, it is possible to reduce the size of the PCB and improve the degree of freedom in the layout of components such as the left electrode 60L1 accordingly.

[0043] According to the embodiment described above, the following operational 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 to the steering wheel 2. The sensor unit 62L1 includes a left electrode 60L1 provided on the steering wheel 2, a measurement 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 such a configuration, for example, unnecessary charges that accumulate in the left electrode 60L1 due to leakage current or the like passing through 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 charges accumulated in the left electrode 60L1 to the measurement unit 68 side. As a result, it becomes possible to appropriately detect the gripping of the steering wheel 2.

[0044] (2) In the steering apparatus 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. The second state includes a third state in which a voltage from a pulse power source 63 as a predetermined power source 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. 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 such a configuration, it becomes possible to perform switching among three modes, namely the first state, the third state, and the fourth state, only by switching the first switch SW1 based on a control signal from the control unit 67.

[0045] (3) In the steering apparatus 1 of (2) above, the charges of the left electrode 60L1 are accumulated in the third state, moved to the charging capacitor 65 in the fourth state, and discharged to the ground line in the first state. With such a configuration, it becomes possible to perform charge accumulation in the left electrode 60L1, charge transfer to the charging capacitor 65 on the measurement unit 68 side, and discharge of unnecessary charges that accumulate in the left electrode 60L1 due to leakage current or the like, only by switching the first switch SW1 based on a control signal from the control unit 67.

[0046] (4) In the steering device 1 of the above (3), for example, in the sensor unit 62L1, at least the first switch SW1, the charging capacitor 65, and the measurement unit 68 are configured on a PCB as an electronic substrate, and at least one of the signal line patterns connecting between the first switch SW1 and the left electrode 60L1, between the first switch SW1 and the pulse power supply 63, and between the first switch SW1 and the charging capacitor 65 is formed close to the ground line. With such a configuration, by selecting the terminal t3 of the first switch SW1 (corresponding to the first state in which the left electrode 60L1 is grounded), an effect equivalent to that of a guard ring for suppressing leakage current can be obtained. That is, even without adopting a guard ring, it is possible to suppress unnecessary charges from accumulating on the left electrode 60L1 via leakage current or the like passing through the surface of the PCB, or unnecessary charges from being generated in the charge transfer path from the left electrode 60L1 to the charging capacitor 65. Therefore, it is possible to suppress the influence on the measurement of the capacitance Ch of the human body H and the floating capacitor E and improve the measurement accuracy. Also, by providing a ground line near the signal line pattern, the electromagnetic coupling between the signal pattern and the ground line becomes stronger, and it becomes possible to prevent crosstalk between the signal pattern and other signal patterns on the PCB. Furthermore, by abolishing the guard ring surrounding the circuit, it becomes possible to miniaturize the PCB and improve the degree of freedom in the layout of components such as the left electrode 60L1 associated therewith.

[0047] (5) In the steering device 1 of the above (1), the steering wheel 2 includes an annular rim portion 20, a hub portion 23 provided inside the rim portion 20, and spoke portions 25L, 25R, 25D extending in the radial direction from the hub portion 23 to connect the hub portion 23 and the inner peripheral portion of the rim portion 20. For example, the sensor unit 62L1 (or the sensor unit 62R1) is disposed in the left auxiliary machine operation console unit (left functional switch portion) 5L disposed on the spoke portion 25L (or the right auxiliary machine operation console unit (right functional switch portion) 5R disposed on the right spoke portion 25R). Generally, it is easier to ensure a larger space inside the spoke portion than the space inside the rim portion. Therefore, by adopting the configuration as described in (5) above, it becomes possible to enhance the productivity as compared with the case of insert molding the sensor unit into the rim portion of the steering wheel.

[0048] (6) In the steering apparatus 1 of the above (5), a plurality of spoke portions 25L, 25R, 25D are provided between the rim portion 20 and the hub portion 23 that are gripped by the occupant. For example, sensor units 62L1 and 62L2, 62R1 and 62R2 are respectively disposed on the left spoke portion 25L and the right spoke portion 25R when viewed from the front of the driver's seat among the plurality of spoke portions 25L, 25R, 25D, and are arranged close to switches and the like as components for performing at least one operation of vehicle information operation or driving support function operation within the left auxiliary machine operation console unit (left function switch portion) 5L and the right auxiliary machine operation console unit (right function switch portion) 5R. With such a configuration, by arranging the PCBs of the sensor units 62L1 and 62L2, 62R1 and 62R2 on the left auxiliary machine operation console unit (left function switch portion) 5L and the right auxiliary machine operation console unit (right function switch portion) 5R that are arranged opposite to the left and right spoke portions 25L, 25R, it becomes possible to appropriately perform grip detection within the recommended grip ranges on the left and right of the rim portion 20.

[0049] (7) In the steering apparatus 1 of the above (6), the sensor unit 62 (62L1, 62L2, 62R1, 62R2) has a configuration other than at least the electrodes 60 (60L1, 60L2, 60R1, 60R2) on the PCB as an electronic substrate. For example, the electrodes 60 of the sensor unit 62 disposed on the spoke portions 25L and 25R are provided in a plurality (60L1, 60L2, 60R1, 60R2) corresponding to the recommended grip ranges, which are predetermined grip ranges of the left rim portion 20 and the right rim portion 20 of the steering handle 2 when viewed from the front, and each is arranged along the end face of the PCB. With such a configuration, for example, it becomes possible to appropriately arrange a plurality of electrodes 60 (60L1, 60L2, 60R1, 60R2) in the space (end faces around the PCB) created by abolishing the guard ring surrounding the circuits of the sensor units 62L1, 62L2, 62R1, and 62R2 and reducing the size of the PCB.

[0050] The above-described embodiment can be modified into various forms. Hereinafter, modification examples will be described. (Modification Example 1) In the embodiment, an annular steering wheel is exemplified as the steering handle 2. However, the present invention may also be applied when using a non-annular rectangular or irregularly shaped steering handle such as a rod shape.

[0051] (Modification Example 2) In the embodiment, four electrodes, namely the first left electrode 60L1, the second left electrode 60L2, the first right electrode 60R1, and the second right electrode 60R2, are exemplified as the plurality of electrodes 60. However, the number of electrodes may be more or less than the four exemplified. Also, four sensor units 62L1, 62L2, 62R1, and 62R2 are exemplified corresponding to the four exemplified electrodes 60L1, 60L2, 60R1, and 60R2. However, the number of sensor units 62 may be increased or decreased according to the number of electrodes 60. Furthermore, in the embodiment, the case where one sensor unit 62 corresponds to one electrode 60 is exemplified. However, a plurality of electrodes 60 may correspond to one sensor unit 62. For example, one sensor unit 62 arranged in the left spoke portion 25L in a front view is made to correspond to the first left electrode 60L1 and the second left electrode 60L2, and another sensor unit 62 arranged in the right spoke portion 25R in a front view is made to correspond 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. In the case of integration, the integrated single sensor unit 62 may be arranged in any of the left spoke portion 25L, the right spoke portion 25R, and the lower spoke portion 25D.

[0052] The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications 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 it is also possible to combine the modifications with each other.

Description of Reference Numerals

[0053] 1 Steering device, 2 Steering wheel, 5L Left auxiliary machine operation console unit (function switch section), 5R Right auxiliary machine operation console unit (function switch section), 6 Gripping 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 Charge capacitor, 67 Control unit, 68 Measurement unit, 69 Detection unit, Ce Floating capacitance, Ch Capacitance, H Human body, RL1,RL2,RR1,RR2 Gripping detection range, SW1 First switch, SW2 Second switch

Claims

1. A steering device including a steering wheel and a sensor unit for detecting contact or proximity of a human body with the steering wheel, The sensor unit includes: An electrode provided on the steering wheel; A measurement unit for measuring the capacitance of the electrode; a switch element for switching between a first state in which the electrode is grounded and a second state in which the electrode is not grounded. A steering device characterized by:

2. 2. The steering device according to claim 1, 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 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. A steering device characterized by:

3. 3. The steering device according to claim 2, a 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:

4. 4. The steering device according to claim 3, The sensor unit includes at least the switch element, the capacitive element, and the measurement unit configured on an electronic substrate, At least one of the signal line patterns respectively connecting between the switch element and the electrode, between the switch element and the predetermined power supply, and between the switch element and the capacitive element is formed in the vicinity of the ground line. A steering device characterized by:

5. 2. The steering device according to 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 periphery of the rim portion, The sensor unit is disposed in a function switch portion disposed in the spoke portion. A steering device characterized by:

6. 6. The steering device according to claim 5, the spoke portion is provided between the rim portion and the hub portion, the spoke portion being gripped by a rider; The sensor unit is disposed in each of the left and right spoke portions of the plurality of spoke portions when viewed from the front of the driver's seat, and is disposed adjacent to a component for performing at least one of vehicle information operation or driving assistance function operation in the function switch portion. A steering device characterized by:

7. 7. The steering device according to claim 6, The sensor unit has at least a configuration other than the electrodes on an electronic substrate, The electrodes are provided in a plurality of positions 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 disposed along an end surface of the electronic board. A steering device characterized by:

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