Gripping device and steering device

Abstract

A gripping detection device comprises a capacitive sensor element mounted on a spoke section of a steering wheel and including a sensing electrode facing a rim section of the steering wheel; a control element configured to control the capacitive sensor element; and a determination element configured to determine the presence or absence of a finger gripping the rim section based on a hover detection result obtained by the capacitive sensor element. The control element uses a core metal of the steering wheel as a shielding electrode for the capacitive sensor element.

Description

Grip detection device and steering device

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

[0002] The following Patent Document 1 discloses a technology that detects whether a person's hand is close to or in contact with a steering wheel by hover detection using 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, the detection value of the capacitance sensor may fluctuate significantly due to noise from the core metal of the steering wheel rim, which may make it impossible to detect a human hand with high accuracy.

[0005] A grip detection device according to one embodiment includes an electrostatic sensor unit provided on the spoke portion of a steering wheel and having a detection electrode facing the rim portion of the steering wheel, a control unit that controls the electrostatic sensor unit, and a judgment unit that judges whether or not there are fingers gripping the rim portion based on the hover detection result by the electrostatic sensor unit, and the control unit uses the core metal of the steering wheel as a shield electrode for the electrostatic sensor unit.

[0006] According to the grip detection device of one embodiment, it is possible to detect the fingers of an operator gripping the rim portion of a steering wheel with high accuracy.

[0007] FIG. 1 is a cross-sectional view of the steering device according to the embodiment taken along the line A-A in FIG. 1; FIG. 2 is an exploded perspective view of the steering device according to the embodiment; FIG. 3 is an external perspective view of the switch unit according to the embodiment; FIG. 4 is an exploded perspective view of the switch unit according to the embodiment; FIG. 5 is a diagram showing the functional configuration of a control device provided in a grip detection device according to the embodiment; FIG. 6 is a diagram showing a comparative example of capacitance detected by the grip detection device according to the embodiment; FIG. 7 is a diagram showing a comparative example of capacitance detected by the grip detection device according to the 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 the steering device 10 according to one embodiment. Fig. 2 is a perspective view of the exterior of the steering device 10 according to one embodiment. Fig. 3 is a cross-sectional view of the steering device 10 according to one embodiment taken along the line A-A in Fig. 1. Fig. 4 is an exploded perspective view of the 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 to operate the steering wheel and various switches of the vehicle.

[0012] As shown in FIGS. 1 and 2, the steering device 10 includes a steering wheel 12, a switch unit 100L, a switch unit 100R, and a connection portion 20.

[0013] The steering wheel 12 is comprised of a rim portion 13 and spokes 14. The rim portion 13 is an annular portion that is gripped by the fingers of the operator's hand to operate the steering wheel. As shown in FIG. 3 , the cross-sectional configuration of the rim portion 13 includes a metallic rim core portion 13A located in the center and a resin (e.g., urethane) covering portion 13B that covers the outer surface of the rim core portion 13A. 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 operator'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 operator's right hand.

[0014] Each spoke 14 has a spoke core metal portion 14A. The spoke core metal portion 14A is a metal portion that extends left-right (in the X-axis direction) on the inside of the steering wheel 12. The left end (negative side of the X-axis) of the spoke core metal portion 14A is connected to the rim core metal portion 13A in the area of ​​the gripping portion 13L of the rim portion 13, and the right end (positive side of the X-axis) is connected to the rim core metal portion 13A in the area of ​​the gripping portion 13R of the rim portion 13. This allows the spoke core metal portion 14A to support the rim portion 13 from the inside. The spoke core metal portion 14A also has a recessed center toward the rear (positive side of the Y-axis). A through hole 14B is provided in the center (on the center axis AX), and is secured to a steering shaft (not shown) inserted through the through hole 14B with a nut (not shown) or the like. As a result, the spoke core metal portions 14A rotate together with the steering wheel 12 in response to steering operation, allowing the steering shaft to rotate about the central axis AX. The spoke core metal portions 14A are made of a metal material and are formed integrally with the rim core metal portion 13A of the rim portion 13. As shown in FIG. 4 , the left end of the spoke core metal portions 14A is formed with an installation surface 14C that faces the operator (negative side of the Y axis) and on which the switch unit 100L is installed. The right end of the spoke core metal portions 14A is formed with an installation surface 14D that faces the operator (negative side of the Y axis) and on which the switch unit 100R is installed. Although not shown in the drawings, in practice the spoke core metal portions 14A are covered with functional parts such as a resin cover or horn.

[0015] The switch units 100L and 100R are mounted on the spoke core 14A to perform various switch operations. The switch unit 100L is mounted on a mounting surface 14C at the left end of the spoke core 14A. The switch unit 100R is mounted on a mounting surface 14D at the right end of the spoke core 14A. The switch units 100L and 100R are roughly rectangular when viewed from the negative side of the Y axis and are symmetrical to each other with respect to a plane passing through the center axis AX. The surface of each switch unit 100L and 100R facing the operator (negative side of the Y axis) forms an operating surface 100A on which various switch operations are performed. In this embodiment, the switch units 100L and 100R are rectangular and symmetrical to each other, and both are equipped with swing-type operating knobs 104, allowing for pressing input operations in four directions. However, this is not limited to this, and the switch units may be of a shape other than rectangular and asymmetrical to each other, and any input means such as a push switch or a toggle switch may be combined as the input means.

[0016] Switch unit 100L is provided near grip portion 13L of rim portion 13 and can detect, without contact, the fingers of the operator's left hand gripping the area of ​​grip portion 13L. Switch unit 100R is provided near grip portion 13R of rim portion 13 and can detect, without contact, the fingers of the operator's right hand gripping the area of ​​grip portion 13R.

[0017] The connection unit 20 is provided to electrically connect the switch units 100L, 100R and the spoke core metal portion 14A to the control device 150 (see FIG. 7 ). The connection unit 20 includes a first cable 21, a second cable 22, a third cable 23, and a connector 24. The first cable 21 connects a terminal (not shown) of the switch unit 100R to the connector 24. The second cable 22 connects a terminal (not shown) of the switch unit 100L to the connector 24. One end of the third cable 23 is fixed to the spoke core metal portion 14A by screwing or other methods, connecting the spoke core metal portion 14A to the connector 24. The connector 24 is connected to the control device 150, thereby connecting the first cable 21, the second cable 22, and the third cable 23 together to the control device 150.

[0018] (Configuration of Switch Unit 100) First, the switch unit 100R will be described. Fig. 5 is a perspective view of the appearance of the switch unit 100R according to one embodiment. Fig. 6 is an exploded perspective view of the switch unit 100R according to one embodiment.

[0019] As shown in FIGS. 5 and 6, the switch unit 100R includes a case 102, an operation knob 104, and an electrostatic sensor unit 110.

[0020] The case 102 is a hollow, resin-made, container-like member. The case 102 has a generally rectangular parallelepiped shape. The surface 102A of the case 102 facing the user is an operation surface 100A on which various switches are operated. An operation knob 104 is provided on the surface 102A for the switch operation. Inside the case 102, a circuit board, switch elements mounted on the circuit board, an actuator for pressing the switch element in response to operation of the operation knob 104, and other components (not shown) are provided. The case 102 is configured by combining an upper case 102B and a lower case 102C. Both the upper case 102B and the lower case 102C have a thin rectangular parallelepiped shape in the Y-axis direction. However, in a plan view from the operator's side (the negative side of the Y-axis), the lower case 102C has a rectangular shape that is slightly smaller than the upper case 102B.

[0021] The electrostatic sensor unit 110 is a sheet-like sensor provided for non-contact electrostatic detection of the grip of the right grip portion 13R of the rim portion 13 by the fingers of the operator's hand, detecting the electrostatic capacitance of the fingers. The electrostatic sensor unit 110 is configured with a flexible substrate 112, and a first detection electrode 114-1 and a second detection electrode 114-2 provided on the flexible substrate 112.

[0022] The flexible substrate 112 is a bendable, insulating, sheet-like resin member. The flexible substrate 112 is bent at right angles in two locations to form a shape that conforms to the three side surfaces of the lower case 102C. Specifically, the flexible substrate 112 has a first flat surface 112A, a second flat surface 112B, and a third flat surface 112C. That is, the flexible substrate 112 is bent at approximately right angles at the boundary between the first flat surface 112A and the second flat surface 112B and the boundary between the second flat surface 112B and the third flat surface 112C.

[0023] The first flat surface 112A is arranged overlapping from approximately the middle of the side surface 102Ca on the upper side (positive side of the Z axis) of the lower case 102C to the first corner C1. The second flat surface 112B is arranged overlapping from the first corner C1 to the second corner C2 on the side surface 102Cb on the right side (positive side of the X axis) of the lower case 102C. The third flat surface 112C is arranged overlapping from approximately the middle of the side surface 102Cc on the lower side (negative side of the Z axis) of the lower case 102C to the second corner C2.

[0024] The first detection electrode 114-1 is bent at a right angle along the first and second planar portions 112A and 112B of the flexible substrate 112 from the first planar portion 112A to the midpoint between the first planar portion 112A and the second planar portion 112B. That is, the first detection electrode 114-1 is bent at a right angle along a first corner C1 (an example of "one of a pair of corners facing the rim portion") on the upper side (positive side of the Z axis) and right side (positive side of the X axis) of the lower case 102C. This allows the first detection electrode 114-1 to detect the capacitance of the fingers of the operator's right hand that are located close to the upper side (positive direction of the Z axis) and right side (positive direction of the X axis) of the case 102. That is, the first detection electrode 114-1 can detect the fingers of the operator gripping the upper (positive Z-axis) region (region closer to one corner) of the grip portion 13R.

[0025] The second detection electrode 114-2 is bent at a right angle along the third planar portion 112C and the second planar portion 112B from the third planar portion 112C to the midpoint between the third planar portion 112C and the second planar portion 112B of the flexible substrate 112. That is, the second detection electrode 114-2 is bent at a right angle along the second corner C2 (an example of the "other of the pair of corners facing the rim portion") on the lower side (negative side of the Z axis) and right side (positive side of the X axis) of the lower case 102C. This allows the second detection electrode 114-2 to detect the capacitance of the fingers of the operator's right hand that are located close to the lower side (negative direction of the Z axis) and right side (positive direction of the X axis) of the case 102. That is, the second detection electrode 114-2 can detect the fingers of the operator gripping the lower (negative Z-axis) area (area closer to the other corner) of the grip portion 13R.

[0026] The detection electrodes 114-1, 114-2 are provided integrally with the switch unit 100R provided on the spoke portion 14 of the steering wheel 12, near the connection area between the rim portion 13 and the spoke portion 14 of the steering wheel 12. The detection electrodes 114-1, 114-2 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).

[0027] The electrostatic sensor unit 110 is attached to the three side surfaces of the lower case 102C by any adhesive means (for example, double-sided tape) on the surface of the flexible substrate 112 facing the lower case 102C.

[0028] The configuration of the switch unit 100R has been described above, but the configuration of the switch unit 100L is almost bilaterally symmetrical to the configuration of the switch unit 100R, and is basically the same configuration as the configuration of the switch unit 100R.

[0029] That is, in the switch unit 100L, the first detection electrode 114-1 is disposed at a first corner C1 (an example of "one of a pair of corners facing the rim") on the upper side (positive side of the Z axis) and left side (negative side of the X axis) of the lower case 102C, and is bent at a substantially right angle along the first corner C1. This allows the first detection electrode 114-1 in the switch unit 100L to detect the hover of the fingers of the operator's left hand that are located close to the upper side (positive direction of the Z axis) and left side (negative direction of the X axis) of the case 102. That is, in the switch unit 100L, the first detection electrode 114-1 can detect the fingers of the operator gripping the upper side (positive side of the Z axis) of the grip portion 13L (the area close to one of the corners).

[0030] Furthermore, in the switch unit 100L, the second detection electrode 114-2 is disposed at a second corner C2 (an example of the "other of the pair of corners facing the rim") on the lower side (negative side of the Z axis) and left side (negative side of the X axis) of the lower case 102C, and is bent at a right angle along the second corner C2. This allows the second detection electrode 114-2 in the switch unit 100L to detect the hover of the fingers of the operator's left hand that are located close to the lower side (negative side of the Z axis) and left side (negative side of the X axis) of the case 102. That is, in the switch unit 100L, the second detection electrode 114-2 can detect the fingers of the operator gripping the lower side (negative side of the Z axis) of the grip portion 13L (the area closer to the other corner).

[0031] 7 is a diagram showing the functional configuration of the control device 150 included in the grip detection device 30 according to one embodiment. The grip detection device 30 according to one embodiment is a device that can determine the presence or absence of fingers of an operator gripping the rim portion 13 (grip portions 13L, 13R) of the steering wheel 12 based on the hover detection result by the electrostatic sensor unit 110, and output the determination result.

[0032] As shown in FIG. 7, the grip detection device 30 according to one embodiment is configured to include a control device 150 and detection electrodes 114-1 and 114-2 of the switch units 100L and 100R, respectively.

[0033] The control device 150 is electrically connected to each of the detection electrodes 114-1 and 114-2 of the switch unit 100R via the first cable 21 and the connector 24.

[0034] The control device 150 is also electrically connected to each of the detection electrodes 114-1 and 114-2 of the switch unit 100L via a second cable 22 and a connector 24.

[0035] The control device 150 is also electrically connected to the rim core portion 13A via the spoke core portions 14A, the third cable 23, and the connector 24.

[0036] As shown in FIG. 7, the control device 150 includes a detection electrode control unit 151 , a shield electrode control unit 152 , a determination unit 153 , and a result output unit 154 .

[0037] The detection electrode control unit 151 detects changes in the capacitance of the detection electrodes 114-1 and 114-2. Specifically, the detection electrode control unit 151 drives the detection electrodes 114-1 and 114-2 by applying a sinusoidal AC voltage as a drive signal to the detection electrodes 114-1 and 114-2. The detection electrodes 114-1 and 114-2 then detect changes in the current value of the current flowing through the detection electrodes 114-1 and 114-2 as changes in capacitance.

[0038] The detection electrodes 114-1 and 114-2 of the switch unit 100R are provided near the grip portion 13R, facing the grip portion 13R. Therefore, when the fingers of the operator's right hand grip the grip portion 13R, the fingers of the operator's right hand are present in close proximity to the detection electrodes 114-1 and 114-2 of the switch unit 100R. As a result, the detection electrodes 114-1 and 114-2 of the switch unit 100R are capacitively coupled with the fingers of the operator's right hand, changing the current value of the current flowing through the detection electrodes 114-1 and 114-2. This allows the detection electrodes 114-1 and 114-2 of the switch unit 100R to perform hover detection (non-contact detection) of the fingers of the operator's right hand. As described above, the detection electrodes 114-1 and 114-2 of the switch unit 100R have a shape that is bent at approximately a right angle, so that the fingers of the operator's right hand can be detected hovering over a range of approximately ±30° on the grip portion 13R, based on the 90° position (positive side of the X-axis) of the rim portion 13.

[0039] In addition, the detection electrodes 114-1 and 114-2 of the switch unit 100L are provided near the grip portion 13L, facing the grip portion 13L. Therefore, when the fingers of the operator's left hand grip the grip portion 13L, the fingers of the operator's left hand are present in close proximity to the detection electrodes 114-1 and 114-2 of the switch unit 100L. As a result, the detection electrodes 114-1 and 114-2 of the switch unit 100L are capacitively coupled with the fingers of the operator's left hand, changing the current value of the current flowing through the detection electrodes 114-1 and 114-2. As a result, the detection electrodes 114-1 and 114-2 of the switch unit 100L can perform hover detection (non-contact detection) of the fingers of the operator's left hand. As described above, the detection electrodes 114-1 and 114-2 of the switch unit 100L have a shape that is bent at approximately a right angle, so that the fingers of the operator's left hand can be detected hovering over a range of approximately ±30° on the grip portion 13L, based on the 270° position (negative side of the X-axis) of the rim portion 13.

[0040] The shield electrode control unit 152 generates an active shield signal and outputs it to the rim core metal portion 13A via the connector 24, the third cable 23, and the spoke core metal portion 14A. This causes the shield electrode control unit 152 to drive the rim core metal portion 13A as an active shield electrode. The active shield signal is, for example, a signal (i.e., a sinusoidal AC voltage) having a waveform synchronized with the drive signal applied to the detection electrodes 114-1 and 114-2 from the detection electrode control unit 151. By driving the rim core metal portion 13A as an active shield electrode, there is no increase in capacitance due to the presence of the rim core metal portion 13A, and noise components applied from the rim core metal portion 13A to the detection electrodes 114-1 and 114-2 can be removed. In other words, the increase in capacitance and noise components due to the rim core metal portion 13A can be removed from the capacitance detected by the detection electrodes 114-1 and 114-2 (see FIG. 8, described below).

[0041] The determination unit 153 determines whether or not the operator's fingers are present gripping the grip portions 13L and 13R, based on the change in capacitance at the detection electrodes 114-1 and 114-2 detected by the detection electrode control unit 151.

[0042] For example, when the difference in capacitance between detection electrodes 114-1 and 114-2 included in switch unit 100R exceeds a predetermined threshold value th, determination unit 153 determines that the fingers of the operator's right hand are present gripping grip portion 13R. Note that, because spoke portions 14 exist, there are cases where fingers are present only above (positive direction of the Z axis) or below (negative direction of the Z axis) grip portion 13R, and therefore determination unit 153 may determine that the fingers of the operator's right hand are present when the measured value or change amount of at least one of detection electrodes 114-1 and 114-2 exceeds a predetermined threshold value.

[0043] Conversely, if the difference in capacitance between the detection electrodes 114-1 and 114-2 of the switch unit 100R is less than the predetermined threshold th, the determination unit 153 determines that there are no fingers of the operator's right hand gripping the grip portion 13R.

[0044] Furthermore, for example, if the difference value of the capacitance between the detection electrodes 114-1 and 114-2 provided in the switch unit 100L exceeds a predetermined threshold th, the determination unit 153 determines that the fingers of the operator's left hand are present gripping the grip portion 13L.

[0045] Conversely, if the difference in capacitance between the detection electrodes 114-1 and 114-2 of the switch unit 100L is less than the predetermined threshold th, the determination unit 153 determines that there are no fingers of the operator's left hand gripping the grip portion 13L.

[0046] A suitable value determined in advance by actual machine testing, simulation, etc. is used for threshold value th. As described above, because control device 150 drives rim core metal portion 13A as an active shield electrode, the capacitance detected by detection electrodes 114-1, 114-2 is the capacitance of rim core metal portion 13A and a value from which noise components from rim core metal portion 13A have been removed by the active shield electrode. For this reason, in this embodiment, threshold value th is used as the value from which the capacitance of rim core metal portion 13A and noise components from rim core metal portion 13A have been removed by the active shield electrode, and therefore is a lower value compared to conventional configurations that do not use an active shield electrode.

[0047] The result output unit 154 outputs the judgment result by the judgment unit 153 (i.e., whether or not the operator's fingers are present gripping the gripping units 13L and 13R) to the outside (e.g., a device that executes processing according to the judgment result by the judgment unit 153).

[0048] The control processing in the control device 150 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 150 shown in FIG. 7 is realized by the processor executing a program stored in a storage medium in the control device 150.

[0049] 8A and 8B are diagrams illustrating a comparative example of capacitance detected by the grip detection device 30 according to an embodiment. Fig. 8A is a diagram illustrating an example of capacitance detected by a conventional grip detection device that does not have an active shield electrode. Fig. 8B is a diagram illustrating an example of capacitance detected by the grip detection device 30 according to an embodiment.

[0050] As shown in Figure 8(a), in conventional grip detection devices without an active shield electrode, the capacitance due to the rim core metal and noise components from the rim core metal are applied to the detection electrode, resulting in the capacitance detected by the detection electrode including the capacitance due to the rim core metal and noise components. However, sensors have a detectable range where the output value remains unchanged even when a certain amount of capacitance is applied, resulting in saturation. Even if a threshold value th for determining the approach of a finger is set near the detectable range, if the capacitance due to the rim core metal and noise components are included, even a slight increase in capacitance can easily exceed the threshold value th. Therefore, conventional grip detection devices cannot accurately detect the operator's finger gripping the steering wheel rim. In other words, it is difficult to improve accuracy because the capacitance component associated with the approach of a finger is small compared to the unnecessary capacitance components (capacitance due to the rim core metal and noise components from the rim core metal).

[0051] On the other hand, as shown in FIG. 8B , the grip detection device 30 according to one embodiment drives the rim core metal portion 13A as an active shield electrode, thereby eliminating the capacitance due to the rim core metal portion 13A and noise components applied from the rim core metal portion 13A to the detection electrodes 114-1 and 114-2. In other words, the grip detection device 30 according to one embodiment can eliminate noise components from the capacitance detected by the detection electrodes 114-1 and 114-2 and detect only the capacitance of the operator's finger. Therefore, the grip detection device 30 according to one embodiment can lower the finger detection threshold th, and the margin between the finger detection threshold th and the sensor's detectable range allows for highly accurate detection of the operator's finger gripping the rim portion 13 of the steering wheel 12. In other words, the capacitance component associated with the approach of a finger is large compared to the unnecessary capacitance components (the capacitance due to the rim core metal portion 13A and the noise components from the rim core metal portion 13A), making it easier to improve accuracy.

[0052] (Example of Circuit Configuration of Grip Detection Device 30) FIGS. 9 to 11 are diagrams showing an example of a circuit configuration 30A of the grip detection device 30 according to an embodiment.

[0053] The circuit configuration 30A shown in FIGS. 9 to 11 includes a signal source 32 (shield electrode control unit 152), a voltage follower circuit 155, a detection electrode 114, and a core 12A (i.e., the rim core 13A and the spoke core 14A) of the steering wheel 12. In the circuit configuration 30A, an active shield signal generated by the signal source 32 is supplied to the core 12A via the voltage follower circuit 155. When the control device 150 (shield electrode control unit 152), which is a signal source with high output impedance, is connected to the shield electrode (core 12A), which is a load with low impedance, the voltage follower circuit 155 ensures that the active shield signal generated by the shield electrode control unit 152 has sufficient voltage and outputs it to the core 12A. In other words, the inclusion of the voltage follower circuit 155 enables the core 12A to be stably driven as an active shield electrode. As a result, in the circuit configuration 30A, the core 12A is driven as an active shield electrode by an active shield signal having a stable voltage, and the capacitance of the core 12A and noise components from the core 12A are removed from the capacitance detected by the detection electrode 114.

[0054] In addition, in the circuit configuration 30A shown in FIG. 9, the voltage follower circuit 155 and the spoke core portion 14A are connected to ground via a Zener diode 35.

[0055] In addition, in the circuit configuration 30A shown in FIG. 10, the voltage follower circuit 155 and the spoke core portion 14A are grounded via the varistor 36.

[0056] In addition, in the circuit configuration 30A shown in FIG. 11, the voltage follower circuit 155 and the spoke core portion 14A are grounded via a clamp diode configuration 37 formed by diodes 37A and 37B.

[0057] As a result, the grip detection device 30 of one embodiment can be driven as an active shield electrode while grounding the rim core metal portion 13A, thereby providing sufficient noise removal effect and ESD (electrostatic discharge) countermeasures by the rim core metal portion 13A.

[0058] (Effects) As described above, the grip detection device 30 according to one embodiment includes an electrostatic sensor unit 110 that is provided on the spoke portion 14 of the steering wheel 12 and has a detection electrode 114 facing the rim portion 13 of the steering wheel 12, a control device 150 that controls the electrostatic sensor unit 110, and a determination unit 153 that determines whether or not fingers are gripping the rim portion 13 based on the hover detection result by the electrostatic sensor unit 110, and the control device 150 uses the core metal of the steering wheel 12 as a shield electrode for the electrostatic sensor unit 110.

[0059] As a result, the grip detection device 30 according to one embodiment can provide a shield electrode without providing a separate member, and therefore can have an inexpensive configuration and suppress the influence of noise on hover detection by the electrostatic sensor unit 110. Therefore, the grip detection device 30 according to one embodiment can detect the fingers of an operator gripping the rim portion 13 of the steering wheel 12 with high accuracy.

[0060] In addition, in the grip detection device 30 according to one embodiment, the control device 150 drives the core metal of the steering wheel 12 as an active shield electrode.

[0061] As a result, the grip detection device 30 according to one embodiment can improve the hover detection performance of the electrostatic sensor unit 110 .

[0062] In addition, in one embodiment of the grip detection device 30, the core of the steering wheel 12 is integrally formed with a rim core portion 13A located at the center of the rim portion 13 and a spoke core portion 14A forming the spoke portion 14, and the control device 150 is connected to the spoke core portion 14A and drives the rim core portion 13A as an active shield electrode via the spoke core portion 14A.

[0063] As a result, in the grip detection device 30 according to one embodiment, the control device 150 can be connected to the spoke core metal portion 14A, and therefore the control device 150 can be easily connected to the core metal of the steering wheel 12.

[0064] Furthermore, in the grip detection device 30 according to one embodiment, the control device 150 drives the active shield electrode with a drive signal having a waveform synchronized with the drive signal of the detection electrode 114 .

[0065] As a result, the grip detection device 30 according to one embodiment can remove noise components from the active shield electrode to the electrostatic sensor unit 110, thereby improving the hover detection performance of the electrostatic sensor unit 110.

[0066] In addition, in the grip detection device 30 according to one embodiment, the detection electrode 114 is provided near the connection area between the rim portion 13 and the spoke portions 14 .

[0067] As a result, the grip detection device 30 according to one embodiment can detect the hover of the operator's fingers gripping the rim portion 13 near the connection area of ​​the spoke portion 14 with high accuracy using the detection electrodes 114 .

[0068] In addition, in the grip detection device 30 according to one embodiment, the detection electrode 114 is provided integrally with the switch unit 100 provided on the spoke portion 14 of the steering wheel 12 .

[0069] As a result, the grip detection device 30 of one embodiment can install the detection electrode 114 in a space-efficient manner, and can detect the hover of the operator's fingers gripping the rim portion 13 with high accuracy using the detection electrode 114.

[0070] In addition, in one embodiment of the grip detection device 30, the switch unit 100 has a pair of corners C1 and C2 at a position opposite the rim portion 13, and the electrostatic sensor portion 110 has a first detection electrode 114-1 that is bent and arranged along the first corner C1 of the pair of corners C1 and C2, and a second detection electrode 114-2 that is bent and arranged along the second corner C2 of the pair of corners.

[0071] As a result, the grip detection device 30 of one embodiment can individually and accurately detect the hover of the fingers gripping the area closer to the first corner C1 of the rim portion 13 and the fingers gripping the area closer to the second corner C2 of the rim portion 13.

[0072] 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.

[0073] For example, in the above embodiment, the rim core metal portion 13A is driven as a so-called active shield electrode, in which a signal whose phase is synchronized with the drive signal applied to the detection electrode is applied to the rim core metal portion 13A. However, this is not limited to this, and the rim core metal portion 13A may also be driven as a so-called passive shield electrode, in which a constant voltage such as ground voltage or power supply voltage is applied to the rim core metal portion 13A.

[0074] Also, for example, in the above embodiment, the rim core metal portion 13A is driven as an active shield electrode via the spoke core metal portion 14A, but this is not limited to this, and the rim core metal portion 13A may also be driven as an active shield electrode without via the spoke core metal portion 14A.

[0075] This international application claims priority based on Japanese Patent Application No. 2021-212504, filed on December 27, 2021, the entire contents of which are incorporated herein by reference.

[0076] REFERENCE SIGNS LIST 10 Steering device 12 Steering wheel 12A Core 13 Rim portion 13A Rim core portion 13B Cover portion 13L Grip portion 13R Grip portion 14 Spoke portion 14A Spoke core portion 14B Through hole 14C, 14D Installation surface 20 Connection portion 21 First cable 22 Second cable 23 Third cable 24 Connector 30 Grip detection device 30A Circuit configuration 32 Signal generating source 35 Zener diode 36 Varistor 37 Clamp diode configuration 37A, 37B Diodes 100, 100L, 100R Switch unit 100A Operation surface 102 Case 102A Surface 102B Upper case 102C Lower case 102Ca, 102Cb, 102Cc Side 104 Operation knob 110 Electrostatic sensor unit 112 Flexible substrate 112A First plane unit 112B Second plane unit 112C Third plane unit 114 Detection electrode 114-1 First detection electrode 114-2 Second detection electrode 150 Control device 151 Detection electrode control unit 152 Shield electrode control unit 153 Determination unit 154 Result output unit 155 Voltage follower circuit AX Central axis th Threshold value

Claims

1. A grip detection device comprising: an electrostatic sensor unit provided on a spoke of a steering wheel and having a detection electrode facing the rim of the steering wheel; a control unit that controls the electrostatic sensor unit; and a determination unit that determines whether or not there are fingers gripping the rim based on the hover detection result by the electrostatic sensor unit, wherein the control unit uses the core metal of the steering wheel as a shield electrode for the electrostatic sensor unit.

2. The grip detection device according to claim 1, characterized in that the control unit drives the core metal of the steering wheel as an active shield electrode.

3. The grip detection device described in claim 2, characterized in that the core of the steering wheel is integrally formed with a rim core portion located at the center of the rim portion and spoke core portions forming the spoke portions, and the control unit is connected to the spoke core portions and drives the rim core portions as the active shield electrode via the spoke core portions.

4. The grip detection device according to claim 2 or 3, characterized in that the control unit drives the active shield electrode with a drive signal having a waveform synchronized with the drive signal of the detection electrode.

5. A grip detection device as described in any one of claims 1 to 4, characterized in that the detection electrode is provided in the vicinity of the connection area between the rim portion and the spoke portion.

6. The grip detection device according to claim 5, characterized in that the detection electrode is provided integrally with a switch unit provided on the spoke portion of the steering wheel.

7. The grip detection device described in claim 6, characterized in that the switch unit has a pair of corners at positions opposite the rim portion, and the electrostatic sensor portion has a first detection electrode that is the detection electrode bent and arranged along one of the pair of corners, and a second detection electrode that is the detection electrode bent and arranged along the other of the pair of corners.

8. A steering device comprising: the steering wheel; and a grip detection device according to any one of claims 1 to 7.

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