Steering device and detection unit

Abstract

This steering device comprises: a rim part that is gripped by a driver; a spoke part that is located adjacent to the rim part; and an electrostatic detection part for detecting the state of the driver's grip on the rim part on the basis of a change in capacitance. The electrostatic detection part includes a detection electrode and an active shield electrode that are provided to the spoke part in a state of facing the rim part. The spoke part has provided thereto a drainage channel that, in the case of having water poured thereon, guides the water to a drain hole to discharge the water. The drain hole, the active shield electrode, the detection electrode, and the rim part are provided in the stated order toward the rim part, in a region near the drain hole.

Description

Steering device and detection unit

[0001] The present invention relates to a steering device and a detection unit.

[0002] The following Patent Document 1 discloses a technology that detects whether a driver's hands are close to or in contact with a steering wheel by detecting with a capacitance sensor provided on the spokes of the steering wheel.

[0003] International Publication No. 2020 / 195620

[0004] However, with the technology of Patent Document 1, if water gets on the spokes of the steering wheel, the water will capacitively couple with the capacitance sensor, causing the detection value of the capacitance sensor to fluctuate significantly, which could make it impossible to detect the driver's hands with high accuracy.

[0005] A steering device according to one embodiment is a steering device that includes a rim portion that is gripped by the driver, spoke portions adjacent to the rim portion, and an electrostatic detection portion that detects the state of the driver's grip on the rim portion by changes in electrostatic capacitance. The electrostatic detection portion has a detection electrode and an active shield electrode that are provided on the spoke portion so as to face the rim portion. The spoke portion is provided with a drainage channel that guides water that is splashed on the vehicle to a drainage hole and discharges it. In the area near the drainage hole, the drainage hole, active shield electrode, detection electrode, and rim portion are provided in this order, facing the rim portion.

[0006] According to the steering device of one embodiment, even if water gets on the spokes of the steering wheel, the driver's hands can be detected with high accuracy.

[0007] 1 is a plan view of a steering device according to an embodiment; 2 is an external perspective view of a detection unit according to an embodiment; 3 is an exploded perspective view of a detection unit according to an embodiment; 4 is a cross-sectional view schematically showing a laminated structure of an electrostatic detection unit provided in a detection unit according to an embodiment; 5 is a diagram showing a configuration of a control system provided in a detection unit according to an embodiment; 6 is a partially enlarged perspective view of a detection unit according to an embodiment;

[0008] Hereinafter, an embodiment will be described with reference to the drawings.

[0009] (Configuration of Steering Device 10) FIG. 1 is a plan view of a steering device 10 according to one embodiment.

[0010] In the following description, for convenience, the X-axis direction will be referred to as the left-right direction, the Y-axis direction as the front-rear direction, and the Z-axis direction as the up-down direction. However, the positive X-axis direction will be referred to as the right direction, the positive Y-axis direction as the forward direction, and the positive Z-axis direction as the upward direction. These directions indicate relative positional relationships within the device and do not limit the installation direction or operation direction of the device. Any devices that have the same relative positional relationship within the device, even if the installation direction or operation direction is different, are all included in the scope of the present invention.

[0011] A steering device 10 shown in FIG. 1 is mounted in the cabin of a vehicle such as an automobile, and is used by a driver to operate the steering wheel and various switches of the vehicle.

[0012] As shown in FIG. 1, the steering device 10 includes a steering wheel 12 and two detection units 100 (detection units 100L and 100R).

[0013] The steering wheel 12 is configured with a rim portion 13 and spoke portions 14. The rim portion 13 is an annular portion that is gripped by the driver's fingers to operate the steering wheel. Although not shown in the figure, the cross-sectional configuration of the rim portion 13 includes a metal rim core portion located in the center and a resin (e.g., urethane) covering portion that covers the outer surface of the rim core portion. The left side (negative side of the X-axis) of the rim portion 13 forms a grip portion 13L that is gripped by the fingers of the driver's left hand. The right side (positive side of the X-axis) of the rim portion 13 forms a grip portion 13R that is gripped by the fingers of the driver's right hand. Note that while both the steering wheel 12 and the rim portion 13 in this embodiment are annular, they are not limited thereto and may have various shapes, such as a special shape in which only the lower portion is connected and the upper portion is cut off, or a rim with a linear portion.

[0014] The spokes 14 are provided inside the rim 13 and support the rim 13 from the inside. In the present embodiment, as an example, the spokes 14 have a central portion 14A provided in the center of the steering wheel 12, a first portion 14B extending in the left-right direction (X-axis direction) from the central portion 14A, and a second portion 14C extending downward (Z-axis direction) from the central portion 14A. In other words, the spokes 14 have a substantially T-shape in a plan view.

[0015] The left-hand (X-axis negative) end of the first portion 14B of the spoke portion 14 is connected to the rim core metal portion of the rim portion 13 in the region of the gripping portion 13L of the rim portion 13, and the right-hand (X-axis positive) end is connected to the rim core metal portion of the rim portion 13 in the region of the gripping portion 13R of the rim portion 13. The lower (Z-axis negative) end of the second portion 14C of the spoke portion 14 is connected to the rim core metal portion of the rim portion 13. In this way, the spoke portion 14 supports the rim portion 13 from the inside.

[0016] The spoke portion 14 is composed of a metal spoke core portion that forms the base of the spoke portion 14, a resin (e.g., urethane) covering portion that covers part of the outer surface of the spoke core portion, and functional parts such as a resin decorative cover and horn that are attached to the surface of the spoke core portion on the driver's side.

[0017] The spokes 14 have through holes 14D formed in the spoke cores of the central portions 14A, and are fixed to a steering shaft (not shown) inserted into the through holes 14D with nuts (not shown) or the like. This allows the spokes 14 to rotate together with the steering wheel 12 in response to steering operation, thereby rotating the steering shaft about the central axis.

[0018] The detection units 100L and 100R are installed on the spoke portion 14 to operate various switches. The detection unit 100L is installed on the left side (negative side of the X axis) of the first portion 14B of the spoke portion 14. The detection unit 100R is installed on the right side (positive side of the X axis) of the first portion 14B of the spoke portion 14. The detection units 100L and 100R have a substantially rectangular shape in a plan view from the driver's side (negative side of the Y axis) and are symmetrical to each other with respect to a plane passing through the center of the steering wheel 12. The driver's side (negative side of the Y axis) surface of each of the detection units 100L and 100R forms an operation surface 100A on which various switches are operated.

[0019] The detection unit 100L is provided near the grip portion 13L of the rim portion 13. The detection unit 100L allows the driver to operate the switches on the operation surface 100A with the fingers of the driver's left hand gripping the area of ​​the grip portion 13L. The detection unit 100L can also detect the state of the grip portion 13L being held by the driver's left hand in a non-contact manner.

[0020] The detection unit 100R is provided near the grip portion 13R of the rim portion 13. The detection unit 100R allows the driver to operate the switches on the operation surface 100A with the fingers of the driver's right hand gripping the grip portion 13R area. The detection unit 100R can also detect the grip state of the grip portion 13R with the driver's right hand in a non-contact manner.

[0021] (Configuration of detection unit 100) The configuration of the detection unit 100 will be described below using the detection unit 100R as a representative example. Fig. 2 is an external perspective view of the detection unit 100R according to one embodiment. Fig. 3 is an exploded perspective view of the detection unit 100R according to one embodiment.

[0022] As shown in FIGS. 2 and 3, the detection unit 100R includes a housing 110 and an electrostatic detection section 120.

[0023] The housing 110 is a resin container-shaped member that is thin in the front-to-rear direction (Y-axis direction) and has an internal space. The housing 110 has a generally rectangular shape when viewed from the driver's side (Y-axis negative side). The housing 110 has a driver-facing side wall 111 that closes the side of the internal space facing the driver (Y-axis negative side), an outer peripheral wall 112 that surrounds the sides of the internal space, and a bottom wall 150 that closes the bottom side of the internal space (Y-axis positive side).

[0024] The driver-facing sidewall 111 of the housing 110 faces the driver via a panel (not shown). Operation knobs 113 for a plurality of switches (an example of a "switch input function") are aligned on the driver-facing sidewall 111 of the housing 110. That is, the surfaces of the operation knobs 113 form an operation surface 100A on which various switch operations are performed. Note that the front surface (positive direction of the Y axis) of the driver-facing sidewall 111 of the housing 110 is uneven due to the formation of drainage channels 115 and the like, but by attaching a panel (not shown) that covers the driver-facing sidewall 111 and the electrostatic detection unit 120, the operation surface 100A, together with the surfaces of the operation knobs 113, forms a smooth, planar operation surface 100A.

[0025] Although not shown, a circuit board and components of each of the multiple switches (such as a switch element provided on the circuit board and an actuator that links the operation knob 113 with the switch element) are provided in the internal space of the housing 110. Each of the multiple operation knobs 113 is provided to penetrate the driver-facing side wall 111 of the housing 110, and when the driver operates the switch, the switch element provided on the circuit board can be activated via the actuator or the like.

[0026] 3 , outer peripheral wall 112 of housing 110 has upper wall 112a, right wall 112b, and lower wall 112c that are provided to surround the upper side (positive side of the Z axis), right side (positive side of the X axis), and lower side (negative side of the Z axis) of driver-facing side wall 111. Portions of upper wall 112a, right wall 112b, and lower wall 112c are provided to protrude toward the driver (negative side of the Y axis) beyond the surface of driver-facing side wall 111 of housing 110.

[0027] Additionally, the outer peripheral wall 112 of the housing 110 has an extension wall 112d that is provided to extend the outer peripheral wall 112. The extension wall 112d has a wall shape that extends downward (in the negative direction of the Z axis) from the left end of the lower wall 112c of the outer peripheral wall 112 along the right side surface of the second portion 14C of the spoke 14.

[0028] The electrostatic detection unit 120 is a sheet-like sensor that is provided to electrostatically and non-contactly detect whether the driver's right hand is gripping the right grip portion 13R of the rim portion 13. The electrostatic detection unit 120 has an overall band-like shape. The electrostatic detection unit 120 is provided on the outer peripheral wall portion 112 of the housing 110.

[0029] Specifically, the electrostatic detection unit 120 is attached with double-sided tape or the like along the surfaces of the upper wall portion 112a, right wall portion 112b, lower wall portion 112c, and extension wall portion 112d of the outer peripheral wall portion 112 of the housing 110. As a result, the electrostatic detection unit 120 is disposed opposite the grip portion 13R of the rim portion 13 provided on the right side (positive direction of the X axis) of the housing 110, and can detect the fingers of the driver's right hand gripping the grip portion 13R in a non-contact manner.

[0030] The configuration of the detection unit 100R has been described above, but the configuration of the detection unit 100L is substantially symmetrical to the configuration of the detection unit 100R, and is basically the same as the configuration of the detection unit 100R.

[0031] 4 is a cross-sectional view schematically illustrating the layered structure of the electrostatic detection unit 120 included in the detection unit 100 according to one embodiment. As shown in Fig. 4, the electrostatic detection unit 120 has a layered structure in which, from the front surface side, a coverlay 121, a detection electrode 122, a base 123, an active shield electrode 124, and a coverlay 125 are layered.

[0032] The base 123 is a flexible, insulating sheet-like member that serves as the base of the electrostatic detection unit 120. In the example shown in Fig. 4, the base 123 has a configuration in which polyimide films 123b are attached to both sides of an intermediate material 123a such as silicone rubber with double-sided tape 123c.

[0033] The detection electrode 122 is formed on the surface of the base portion 123. The detection electrode 122 is provided to electrostatically detect the finger of the driver's hand that is close to the detection electrode in a non-contact manner.

[0034] The active shield electrode 124 is formed on the back surface of the base 123. The active shield electrode 124 is driven by a drive signal synchronized with the drive signal of the detection electrode 122, thereby making it possible to remove noise components that are applied to the detection electrode 122 from the back side of the detection electrode 122.

[0035] The detection electrode 122 and the active shield electrode 124 are made of a thin film conductor such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or a metal film (e.g., a composite material of silver, copper, aluminum, and molybdenum).

[0036] The coverlay 121 is a resin film-like member that is provided over the surface of the base 123 on which the detection electrodes 122 are formed. The coverlay 125 covers the surface of the base 123 to protect the surface of the base 123 and the detection electrodes 122.

[0037] The coverlay 125 is a resin film-like member that is provided on the back surface of the base 123 on which the active shield electrode 124 is formed. The coverlay 125 covers the back surface of the base 123, thereby protecting the back surface of the base 123 and the active shield electrode 124.

[0038] The electrostatic detection unit 120 having the above-described laminated structure has its back surface (the surface on the coverlay 125 side) attached to the surface of the outer peripheral wall 112 (the upper wall 112a, the right wall 112b, the lower wall 112c, and the extended wall 112d) of the housing 110. As a result, the electrostatic detection unit 120 is provided so that the detection electrode 122 and the active shield electrode 124 face the grip portion 13R of the rim portion 13 on the spoke portion 14 of the steering wheel 12. This allows the electrostatic detection unit 120 to detect the fingers of the driver gripping the grip portion 13R in a non-contact manner using the detection electrode 122. At this time, the electrostatic detection unit 120 can remove noise components applied to the detection electrode 122 from the housing 110 side on the back side of the electrostatic detection unit 120 using the active shield electrode 124.

[0039] (Configuration of the control system included in the detection unit 100)

[0040] Fig. 5 is a diagram showing the configuration of a control system included in the detection unit 100 according to one embodiment. As shown in Fig. 5, the control system included in the detection unit 100 includes the detection electrode 122 and active shield electrode 124, which have already been described, and a control device 130. The configuration of the control system of the detection unit 100 shown in Fig. 5 is common to the detection units 100L and 100R.

[0041] The control device 130 is a device that can determine whether or not the driver's fingers are gripping the rim portion 13 (grip portions 13L, 13R) of the steering wheel 12 based on the detection results from the detection electrode 122, and output the determination result.

[0042] 5, the control device 130 is electrically connected to each of the detection electrode 122 and the active shield electrode 124. The control device 130 includes a detection electrode control unit 131, a shield electrode control unit 132, a determination unit 133, and a result output unit 134.

[0043] The detection electrode control unit 131 detects a change in capacitance in the detection electrode 122. Specifically, the detection electrode control unit 131 drives the detection electrode 122 by applying an AC voltage consisting of a sine wave as a drive signal to the detection electrode 122. Then, the detection electrode 122 detects a change in the current value of the current flowing through the detection electrode 122 as a change in capacitance.

[0044] For example, the detection electrode 122 of the detection unit 100R is provided near the grip portion 13R, facing the grip portion 13R. Therefore, when the fingers of the driver's right hand grip the grip portion 13R, the fingers of the driver's right hand are located close to the detection electrode 122 of the detection unit 100R. As a result, the detection electrode 122 of the detection unit 100R is capacitively coupled with the fingers of the driver's right hand, causing a change in the value of the current flowing through the detection electrode 122. This allows the detection electrode 122 of the detection unit 100R to detect (non-contact detection) the fingers of the driver's right hand.

[0045] As shown in Figures 2 and 3, the electrostatic detection section 120 of the detection unit 100R has a shape that is bent at approximately right angles at the upper right corner and the lower right corner of the housing 110, so that it can detect the fingers of the driver's right hand within a range of approximately ±30° at the grip section 13R, based on the 90° position (positive side of the X-axis) of the rim section 13.

[0046] The shield electrode control unit 132 generates an active shield signal and outputs the active shield signal to the active shield electrode 124. In this way, the shield electrode control unit 132 drives the active shield electrode 124. The active shield signal is, for example, a signal (i.e., an AC voltage consisting of a sine wave) having a waveform synchronized with the drive signal applied to the detection electrode 122 from the detection electrode control unit 131. When the active shield electrode 124 is driven, it can remove noise components applied to the detection electrode 122 from the back side (the housing 110 side) of the active shield electrode 124. In other words, the active shield electrode 124 can remove noise components from the capacitance detected by the detection electrode 122.

[0047] The determination unit 133 determines whether or not the driver's fingers are gripping the grip portions 13L and 13R based on the change in capacitance in the detection electrodes 122 detected by the detection electrode control unit 131.

[0048] For example, if the difference value between the reference value of the capacitance of the detection electrode 122 provided in the detection unit 100R exceeds a predetermined threshold value th, the judgment unit 133 judges that the fingers of the driver's right hand are gripping the grip portion 13R.

[0049] Conversely, if the difference value between the reference value of the capacitance of the detection electrode 122 provided in the detection unit 100R is less than a predetermined threshold value th, the judgment unit 133 determines that there are no fingers on the driver's right hand gripping the grip portion 13R.

[0050] The reference value is a value set assuming a capacitance value when the driver's finger or the like is not in proximity.

[0051] The threshold value th is set to a suitable value determined in advance by actual device testing, simulation, or the like. As described above, the control device 130 drives the active shield electrode 124, and therefore the capacitance detected by the detection electrode 122 is one from which noise components from the back side (housing 110 side) of the detection electrode 122 have been removed. For this reason, in this embodiment, the threshold value th is set to a value from which noise components from the back side (housing 110 side) of the detection electrode 122 have been removed by the active shield electrode 124, and therefore the threshold value th is lower than that of a conventional configuration that does not use an active shield electrode.

[0052] The result output unit 134 outputs the judgment result by the judgment unit 133 (i.e., whether or not the driver's fingers are gripping the gripping portions 13L, 13R) to the outside (for example, a device that executes processing according to the judgment result by the judgment unit 133).

[0053] The control device 130 is realized by, for example, a computer (for example, an integrated circuit (IC)) equipped with a processor (for example, a CPU), a storage medium (for example, a read-only memory (ROM), a random access memory (RAM), a solid-state drive (SSD), etc.), an external interface, etc. For example, the control processing in each functional unit of the control device 130 shown in FIG. 5 is realized by the processor executing a program stored in a storage medium in the control device 130.

[0054] (Drainage Configuration of Detection Unit 100) Fig. 6 is a partially enlarged perspective view of the detection unit 100R according to one embodiment. Fig. 7 is a plan view of the detection unit 100R according to one embodiment as viewed from the positive direction of the Y axis.

[0055] As shown in FIG. 6, the housing 110 of the detection unit 100R has a drainage channel 115 on the surface of the driver-facing side wall 111 for draining water that has fallen on the surface of the driver-facing side wall 111.

[0056] The drainage channel 115 is provided on the surface of the driver-facing sidewall 111 and along the lower wall 112c of the outer peripheral wall 112 of the housing 110. When the steering device 10 is in the neutral steering position, the lower wall 112c is inclined downward to the right with respect to a horizontal plane that is level with the ground (a horizontal plane parallel to the X-axis). Therefore, water that enters through a gap between the operation knob 113 and a panel (not shown) covering the driver-facing sidewall 111 and the electrostatic detection unit 120 and covers the surface of the driver-facing sidewall 111 flows toward the lower wall 112c due to gravity, and further flows along the lower wall 112c toward the lower right corner (the corner on the positive side of the X-axis and the negative side of the Z-axis) of the driver-facing sidewall 111, which is downstream of the drainage channel 115 (the arrow (115) indicates the direction of water flow).

[0057] A drain hole 116 is formed in the lower right corner of the driver-facing side wall 111. The drain hole 116 penetrates the interior of the housing 110 in the front-to-rear direction (Y-axis direction) and has a generally triangular shape that is flat when viewed from the Y-axis direction (its width in the Z-axis direction is short and its width in the X-axis direction is long). That is, the drain hole 116 is formed at the most downstream position in the direction of gravity on the drain channel 115. Note that the shape of the drain hole 116 is not limited to the above-described generally triangular shape, but may be any shape suitable for the available space, such as an oval or a square. The drain channel 115 and the drain hole 116 are provided between the outer peripheral wall 112 and the operation knob 113. However, they may be spaced apart from the detection electrode 122 and the active shield electrode 124. For example, the drain channel 115 and the drain hole 116 may be located directly below the operation knob 113.

[0058] As a result, when the operation surface 100A of the detection unit 100R becomes wet, water seeps in through the gaps in the operation surface 100A, and the water that has wet the surface of the driver-facing side wall portion 111 flows downstream through the drainage channel 115 according to gravity and is discharged to the back side of the housing 110 (positive side of the Y axis) through the drainage hole 116 formed at the most downstream side of the drainage channel 115.

[0059] Near drain hole 116, an outer peripheral wall 112 (lower wall 112c and right wall 112b) of housing 110 is provided so as to surround the lower side (negative side of the Z axis) and right side (positive side of the X axis) of drain hole 116. In addition, an electrostatic detection unit 120 having a detection electrode 122 for detecting gripping of grip portion 13R by the driver's right hand is provided on the outer surface of outer peripheral wall 112.

[0060] Here, if water that has splashed onto the surface of the driver-facing side wall portion 111 adheres to the electrostatic detection portion 120, the water and the detection electrode 122 will be capacitively coupled, and there is a risk that noise components will be included in the electrostatic capacitance detected by the detection electrode 122.

[0061] However, the electrostatic detection unit 120 of this embodiment can guide water that has fallen on the surface of the driver-facing side wall 111 when the operation surface 100A is wet to the drainage channel 115 to the drainage hole 116 and discharge it from the drainage hole 116 to the back side (positive side of the Y axis) of the housing 110 without allowing it to adhere to the electrostatic detection unit 120. Therefore, the electrostatic detection unit 120 of this embodiment can prevent water that has fallen on the surface of the driver-facing side wall 111 when the operation surface 100A is wet from adhering to the electrostatic detection unit 120.

[0062] Furthermore, if water flowing through the drainage channel 115 remains on the inner wall of the drainage hole 116 or in its vicinity, the water may become capacitively coupled to the detection electrode 122, and the electrostatic capacitance detected by the detection electrode 122 may contain noise components.

[0063] However, in the electrostatic detection unit 120 of this embodiment, the active shield electrode 124 is provided on the back side of the detection electrode 122 (i.e., on the drain hole 116 side), and the active shield electrode 124 can block the capacitive coupling of water remaining on or near the inner wall of the drain hole 116 to the detection electrode 122.

[0064] Furthermore, as shown in FIG. 6, the electrostatic detection unit 120 of this embodiment has a gap portion 126 that does not have a detection electrode 122 in the portion that overlaps with the outer wall portion 112 at the lower right corner of the housing 110 where the drainage hole 116 is provided.

[0065] As a result, the electrostatic detection unit 120 of this embodiment can greatly separate the detection electrode 122 from water remaining on the inner wall of or near the drain hole 116, thereby preventing the water remaining on the inner wall of or near the drain hole 116 from flowing around the outside of the active shield electrode 124 and capacitively coupling with the detection electrode 122.

[0066] Moreover, in the electrostatic detection unit 120 of this embodiment, the width of the detection electrodes in the Y-axis direction is generally smaller than the width of the active shield electrode 124 in the Y-axis direction.

[0067] As a result, the electrostatic detection unit 120 of this embodiment can prevent water remaining on the inner wall of or near the drain hole 116 from flowing around the outside of the active shield electrode 124 and capacitively coupling with the detection electrode 122.

[0068] 8(c), a second active shield electrode (AS) adjacent to the detection electrode 122 (sensor) may be further provided in the gap 126. This makes it possible to further prevent water remaining on the inner wall of the drain hole 116 or in its vicinity from being capacitively coupled with the detection electrode 122 through the gap 126.

[0069] Comparative Examples An example of the electrostatic detection unit 120 according to an embodiment and a comparative example will be described below with reference to FIG. 8 . FIG. 8( a) is a diagram illustrating a comparative example of the electrostatic detection unit 120 according to an embodiment, and schematically illustrates the configuration of an electrostatic detection unit using a self-capacitance method without an active shield (AS). FIG. 8( b) is a diagram illustrating the configuration of a first example of the electrostatic detection unit 120 according to an embodiment, using a self-capacitance method with an active shield electrode (AS) (a configuration without a gap 126). FIG. 8( c) is a diagram illustrating the configuration of a second example of the electrostatic detection unit 120 according to an embodiment, using a self-capacitance method with an active shield electrode (AS) (a configuration with a gap 126), and corresponds to the example illustrated in FIGS. 1 to 7 .

[0070] In the configuration of the electrostatic detection unit shown in Figure 8 (a), if the dielectric constant of the dielectric is ε, the area S of the water (W) is "1", and the distance D from the water (W) to the end of the detection electrode (Sensor) is "1", the electrostatic capacitance Ca capacitively coupled from the water (W) to the detection electrode can be calculated using the following equation (1).

[0071] Ca=ε×(S / D)=ε(1 / 1)=ε...(1)

[0072] Here, if the drive voltage of the detection electrode is set to 2 V, and the potential difference between GND and the detection electrode (Sensor) is set to 2 V, the amount of charge Qa detected by the detection electrode can be calculated using the above formula (1) and the following formula (2).

[0073] Qa=CaV=Ca*(2-0)=2Ca=2ε...(2)

[0074] Therefore, the degree of influence of water (W) on the capacitance detection electrode is "2".

[0075] In the first example configuration of the electrostatic detection unit 120 shown in Figure 8(b), as in Figure 8(a), if the dielectric constant of the dielectric is ε, the area S of the water (W) is "1", and the distance D from the water (W) to the end of the detection electrode is "1", the electrostatic capacitance Cb capacitively coupled from the water (W) to the detection electrode 122 can be calculated using the following equation (3).

[0076] Cb=ε×(S / D)=ε(1 / 1)=ε...(3)

[0077] Here, if the drive voltage of the detection electrode 122 (Sensor) is 2 V and the drive voltage of the active shield electrode 124 (AS) is 2.2 V, and the potential difference between the active shield electrode 124 (AS) and the detection electrode 122 (Sensor) is −0.2 V, the amount of charge Qb detected by the detection electrode 122 (Sensor) can be calculated using the above formula (3) and the following formula (4):

[0078] Qb=CbV=Cb*(2-2.2)=-0.2Cb=-0.2ε...(4)

[0079] Therefore, the degree of influence of water (W) on the capacitance detection electrode is "0.2", that is, 1 / 10 compared to the configuration without the active shield electrode 124 (AS) shown in FIG. 8(a).

[0080] In the second example configuration of the electrostatic detection unit 120 shown in Figure 8(c), as in Figure 8(a), the dielectric constant of the dielectric is ε and the area S of the water (W) is "1", but if the distance from the water (W) to the end of the detection electrode is the sum of the distance D "1" and the width α "1" of the gap portion 126, the electrostatic capacitance Cc capacitively coupled from the water (W) to the detection electrode 122 (Sensor) can be calculated using the following equation (5).

[0081] Cc=ε×(S / (D+α))=ε(1 / (1+1))=0.5ε...(5)

[0082] Here, if the drive voltage of the detection electrode 122 (Sensor) is 2 V and the drive voltage of the active shield electrode 124 (AS) is 2.2 V, and the potential difference between the active shield electrode 124 (AS) and the detection electrode 122 (Sensor) is −0.2 V, the amount of charge Qc detected by the detection electrode 122 (Sensor) can be calculated using the above equation (5) and the following equation (6).

[0083] Qc=CcV=Cc*(2-2.2)=-0.2Cc=-0.1ε...(6)

[0084] Therefore, the degree of influence of water (W) on the capacitance detection electrode is "0.1", that is, 1 / 20 of the influence of the configuration shown in FIG. 8A without the active shield electrode 124 (AS).

[0085] The set values ​​of the parameters S, D, and α used in the above example are simply used as reference values ​​to make the effects easier to understand, and are not limited to these set values, and the set values ​​of the parameters S, D, and α are variable. However, regardless of the set values ​​of the parameters S, D, and α, in either case, it is clear that the configurations of the first and second examples of the electrostatic detection unit 120 according to an embodiment are less susceptible to the effects of water (W) than a configuration of an electrostatic detection unit that does not have an active shield electrode 124 (AS).

[0086] (Effects) As described above, the steering device 10 according to one embodiment is a steering device 10 that includes a rim portion 13 that is gripped by the driver, spoke portions 14 that are adjacent to the rim portion 13, and an electrostatic detection unit 120 that detects the state of the driver's grip on the rim portion 13 by a change in electrostatic capacitance, and the electrostatic detection unit 120 has a detection electrode 122 and an active shield electrode 124 that are provided on the spoke portion 14 so as to face the rim portion 13, and the spoke portion 14 is provided with a drainage channel 115 that guides water that is splashed on the vehicle to a drainage hole 116 and drains it away, and in the area near the drainage hole 116, the drainage hole 116, the active shield electrode 124, the detection electrode 122, and the rim portion 13 are provided in this order toward the rim portion 13.

[0087] As a result, in one embodiment of the steering device 10, even if water remains on or near the inner wall of the drain hole 116 of the drain channel 115, the active shield electrode 124 can cancel the effect of the remaining water, so the driver's grip state can be accurately detected.

[0088] In addition, in the steering device 10 according to one embodiment, the electrostatic detection section 120 is provided in the spoke section 14 as the detection unit 100 having the housing 110 .

[0089] As a result, the steering device 10 according to one embodiment can detect the driver's grip on the steering wheel 12 simply by attaching the detection unit 100 to the spoke portion 14 without making any major modifications to the steering wheel 12 .

[0090] In addition, in one embodiment of the steering device 10, the detection electrode 122 and the active shield electrode 124 are provided on the outer peripheral wall portion 112 (outer peripheral portion) of the housing 110 of the detection unit 100, and the drain hole 116 is spaced apart from the detection electrode 122 and the active shield electrode 124 and is provided so as to penetrate the inside of the housing 110.

[0091] As a result, in one embodiment of the steering device 10, the detection electrode 122 is provided on the outer wall portion 112 (outer periphery) of the housing 110 so as to make it easier to detect the driver's grip state, and the drain hole 116 is provided inside the housing 110 so as not to interfere with the detection electrode 122, so that the detection electrode 122 and the drain hole 116 can be arranged in a space-efficient manner.

[0092] In addition, in the steering device 10 according to one embodiment, the detection unit 100 has a plurality of switches (switch input functions).

[0093] As a result, the steering device 10 according to one embodiment can use the housing 110 of the electrostatic detection unit 120 as well as the switch input function, resulting in good space efficiency.

[0094] In addition, in the steering device 10 according to one embodiment, the drainage channel 115 is provided to guide water to the drainage hole 116 when the steering device is in the neutral steering position.

[0095] As a result, the steering device 10 according to one embodiment can reliably drain water when submerged in water when the steering device is in the neutral steering position, which is the state that is most likely to occur.

[0096] In addition, the detection unit 100 of one embodiment is a detection unit 100 that is provided on the spoke portion 14 of a steering device 10 that has a rim portion 13 that is gripped by the driver and a spoke portion 14 adjacent to the rim portion 13, and includes a housing 110 and an electrostatic detection portion 120 that detects the state of the driver's grip on the rim portion 13 by a change in electrostatic capacitance, and the electrostatic detection portion 120 has a detection electrode 122 and an active shield electrode 124 that are provided on the housing 110 so as to face the rim portion 13, and the housing 110 is provided with a drainage channel 115 that guides water that is splashed on the vehicle to a drainage hole 116 and discharges it, and in the area near the drainage hole 116, the drainage hole 116, the active shield electrode 124, and the detection electrode 122 are provided in this order toward the rim portion 13.

[0097] As a result, the detection unit 100 according to one embodiment can detect the driver's grip by simply attaching it to the spoke portion 14 without making any significant modifications to the steering wheel 12 .

[0098] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0099] REFERENCE SIGNS LIST 10 Steering device 12 Steering wheel 13 Rim portion 13L Grip portion 13R Grip portion 14 Spoke portion 14A Central portion 14B First portion 14C Second portion 14D Through hole 100, 100L, 100R Detection unit 100A Operation surface 110 Housing 111 Driver-facing side wall portion 112 Outer wall portion 112a Upper wall portion 112b Right wall portion 112c Lower wall portion 112d Extension wall portion 113 Operation knob 115 Drainage channel 116 Drainage hole 120 Electrostatic detection portion 121 Coverlay 122 Detection electrode (Sensor) 123 Base portion 123a Intermediate material 123b Polyimide film 123c Double-sided tape 124 Active shield electrode (AS) 125 Coverlay 130 Control device 131 Detection electrode control unit 132 Shield electrode control unit 133 Determination unit 134 Result output unit th Threshold value W Water

Claims

1. A steering device comprising a rim portion gripped by a driver, a spoke portion adjacent to the rim portion, and an electrostatic detection unit that detects the state of the driver's grip on the rim portion based on a change in capacitance, wherein the electrostatic detection unit has a detection electrode and an active shield electrode provided on the spoke portion so as to face the rim portion, a drainage channel is provided in the spoke portion to guide and discharge water when the spoke portion is wetted, and in a region near the drainage hole, the drainage hole, the active shield electrode, the detection electrode, and the rim portion are provided in this order toward the rim portion.

2. The steering device according to claim 1, wherein the electrostatic detection unit is provided in the spoke portion as a detection unit having a housing.

3. The steering device according to claim 2, wherein the detection electrode and the active shield electrode are provided on an outer peripheral portion of the housing of the detection unit, and the drainage hole is provided so as to be separated from the detection electrode and the active shield electrode and penetrate through the inside of the housing.

4. The steering device according to claim 2, wherein the detection unit has a switch input function.

5. The steering device according to any one of claims 1 to 4, wherein the drainage channel is provided to guide the water to the drainage hole in a state where the steering device is in a neutral steering position.

6. A detection unit provided in a spoke portion of a steering device including a rim portion gripped by a driver and a spoke portion adjacent to the rim portion, the detection unit comprising a housing and an electrostatic detection unit that detects the state of the driver's grip on the rim portion based on a change in capacitance, wherein the electrostatic detection unit has a detection electrode and an active shield electrode provided on the housing so as to face the rim portion, a drainage channel is provided in the housing to guide and discharge water when the housing is wetted, and in a region near the drainage hole, the drainage hole, the active shield electrode, and the detection electrode are provided in this order toward the rim portion.

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