Grip detection device and steering device

Abstract

Provided is a gripping detection device comprising electrostatic sensor units each of which is provided to a spoke portion of a steering wheel and includes a detection electrode opposing a rim portion of the steering wheel, a control unit which controls the electrostatic sensor units, and a determination unit which determines whether or not the fingers holding the rim portion are present on the basis of a hovering detection result by the electrostatic sensor units, wherein the control unit uses a metal core of the steering wheel as a shield electrode of the electrostatic sensor units.

Description

Technical Field

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

Background Art

[0002] The following Patent Document 1 discloses a technique for detecting whether a person's hand is present in proximity to or in contact with a steering wheel by hover detection of a capacitance sensor provided in a spoke portion of the steering wheel.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique of Patent Document 1, the detection value of the capacitance sensor is greatly affected by noise from the rim core of the steering wheel and may fluctuate, making it impossible to accurately detect a person's hand.

Means for Solving the Problems

[0005] A gripping detection device according to an embodiment includes an electrostatic sensor unit provided in a spoke portion of a steering wheel and having a detection electrode facing a rim portion of the steering wheel, a control unit that controls the electrostatic sensor unit, and a determination unit that determines the presence or absence of fingers gripping the rim portion based on a hover detection result by the electrostatic sensor unit. The control unit uses the core of the steering wheel as a shield electrode of the electrostatic sensor unit.

Effects of the Invention

[0006] According to the gripping detection device according to one embodiment, it is possible to highly accurately detect the fingers of an operator who grips the rim portion of the steering wheel.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[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 an embodiment. FIG. 2 is an external perspective view of the steering device 10 according to an embodiment. FIG. 3 is a cross-sectional view of the steering device 10 according to an embodiment taken along the A-A cross-section line in FIG. 1. FIG. 4 is an exploded perspective view of the steering device 10 according to an embodiment.

[0010] In the following description, for convenience, the X-axis direction is the left-right direction, the Y-axis direction is the front-rear direction, and the Z-axis direction is the up-down direction. However, the positive direction of the X-axis is the right direction, the positive direction of the Y-axis is the front direction, and the positive direction of the Z-axis is the up direction. These indicate the relative positional relationship within the device and do not limit the installation direction or operation direction of the device. All those with the same relative positional relationship within the device, regardless of whether the installation direction or operation direction is different, are included in the scope of the rights of the present invention.

[0011] The steering device 10 shown in FIG. 1 is mounted in the passenger compartment of a vehicle such as an automobile and is a device for performing steering wheel operation and various switch operations 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 configured to have a rim portion 13 and a spoke portion 14. The rim portion 13 is an annular portion that is gripped by the fingers of the operator's hand to perform steering operation. As shown in FIG. 3, the cross-sectional configuration of the rim portion 13 has a metallic rim core portion 13A disposed at the center and a resin (e.g., urethane) coating portion 13B that covers the outer surface of the rim core portion 13A. The region on the left side (negative X-axis side) of the rim portion 13 is a gripping portion 13L that is gripped by the fingers of the operator's left hand. The region on the right side (positive X-axis side) of the rim portion 13 is a gripping portion 13R that is gripped by the fingers of the operator's right hand.

[0014] The spoke portion 14 has a spoke core metal portion 14A. The spoke core metal portion 14A is a metal part that extends in the left - right direction (X - axis direction) inside the steering wheel 12. The left - hand end (negative X - axis side) of the spoke core metal portion 14A is connected to the rim core metal portion 13A in the region of the gripping portion 13L of the rim portion 13, and the right - hand end (positive X - axis side) is connected to the rim core metal portion 13A in the region of the gripping portion 13R of the rim portion 13. Thereby, the spoke core metal portion 14A supports the rim portion 13 from the inside. Also, the spoke core metal portion 14A has a shape in which the central portion is recessed toward the back side (positive Y - axis side), and in the through - hole 14B provided at the central portion (on the central axis AX), it is fixed to a steering shaft (not shown) inserted into the through - hole 14B with a nut (not shown) or the like. Thereby, the spoke core metal portion 14A rotates together with the steering wheel 12 with the handle operation and can rotate the steering shaft around the axis of the central axis AX. Note that the spoke core metal portion 14A is made of a metal material and is integrally formed with the rim core metal portion 13A of the rim portion 13. Also, as shown in FIG. 4, on the left - hand end of the spoke core metal portion 14A, an installation surface 14C is formed that faces the operator side (negative Y - axis side) and on which the switch unit 100L is installed. Also, on the right - hand end of the spoke core metal portion 14A, an installation surface 14D is formed that faces the operator side (negative Y - axis side) and on which the switch unit 100R is installed. Although not shown, actually, the spoke core metal portion 14A is covered with functional parts such as a resin cover and a horn.

[0015] The switch units 100L and 100R are installed on the spoke core metal part 14A to perform various switch operations. The switch unit 100L is installed on the installation surface 14C at the left end of the spoke core metal part 14A. The switch unit 100R is installed on the installation surface 14D at the right end of the spoke core metal part 14A. The switch units 100L and 100R are generally rectangular in shape when viewed from the negative Y-axis side, and have a left-right symmetric shape with respect to the plane passing through the central axis AX. The surface on the operator side (negative Y-axis side) of each of the switch units 100L and 100R is an operation surface 100A where various switch operations are performed. In this embodiment, the switch units 100L and 100R are rectangular and symmetric about the left and right, and both are provided with a swing-type operation knob 104, enabling a pressing input operation in four directions. However, the present invention is not limited to this, and they may have a shape other than a rectangular shape that is asymmetric about the left and right, or any input means such as a push switch or a toggle switch may be combined as the input means.

[0016] The switch unit 100L is provided near the gripping part 13L of the rim part 13, and can non-contact detect the fingers of the operator's left hand that grip the area of the gripping part 13L. The switch unit 100R is provided near the gripping part 13R of the rim part 13, and can non-contact detect the fingers of the operator's right hand that grip the area of the gripping part 13R.

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

[0018] (Configuration of Switch Unit 100) First, the switch unit 100R will be described. FIG. 5 is an external perspective view of the switch unit 100R according to an embodiment. FIG. 6 is an exploded perspective view of the switch unit 100R according to an 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 resin-made and container-shaped member having a hollow structure. The case 102 generally has a rectangular parallelepiped shape. The surface 102A facing the user of the case 102 serves as an operation surface 100A where various switch operations are performed. An operation knob 104 for performing a switch operation is provided on the surface 102A. Inside the case 102, a circuit board, a switch element mounted on the circuit board, an actuator for pressing the switch element in accordance with the operation of the operation knob 104, etc. are provided (not shown). 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 side (Y-axis negative side), 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-shaped sensor provided for non-contact detection of the gripping of the gripping portion 13R on the right side of the rim portion 13 by the finger of the operator's hand by an electrostatic method that detects the electrostatic capacitance of the finger. The electrostatic sensor unit 110 includes a flexible substrate 112, a first detection electrode 114-1 provided on the flexible substrate 112, and a second detection electrode 114-2.

[0022] The flexible substrate 112 is a resin-made and sheet-shaped member that is foldable and has insulating properties. The flexible substrate 112 has a shape along three side surfaces of the lower case 102C by being bent at right angles at two locations. Specifically, the flexible substrate 112 has a first flat portion 112A, a second flat portion 112B, and a third flat portion 112C. That is, the flexible substrate 112 is bent at a substantially right angle at the boundary between the first flat portion 112A and the second flat portion 112B, and at the boundary between the second flat portion 112B and the third flat portion 112C.

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

[0024] The first detection electrode 114-1 is disposed being bent at a right angle along the first flat portion 112A and the second flat portion 112B from the first flat portion 112A of the flexible substrate 112 to the middle position of the second flat portion 112B. That is, the first detection electrode 114-1 is disposed being bent at a right angle along the first corner portion C1 (an example of "one of the pair of corner portions facing the rim portion") on the upper side (positive Z-axis side) and the right side (positive X-axis side) of the lower case 102C. Thereby, the first detection electrode 114-1 can hover-detect the capacitance of the fingers of the right hand of an operator existing in the vicinity above (positive Z-axis direction) and to the right (positive X-axis direction) of the case 102. That is, the first detection electrode 114-1 can detect the finger of an operator who grips the upper region (the region closer to one corner portion) (positive Z-axis side) in the gripping portion 13R.

[0025] The second detection electrode 114-2 is arranged to be bent at a right angle along the third flat portion 112C and the second flat portion 112B from an intermediate position between the third flat portion 112C and the second flat portion 112B of the flexible substrate 112. That is, the second detection electrode 114-2 is arranged to be bent at a right angle along the second corner C2 (an example of "the other corner of the pair of corners facing the rim portion") on the lower side (negative Z-axis side) and the right side (positive X-axis side) of the lower case 102C. Thereby, the second detection electrode 114-2 can hover-detect the capacitance of the fingers of the right hand of an operator existing in the vicinity below (negative Z-axis direction) and to the right (positive X-axis direction) of the case 102. That is, the second detection electrode 114-2 can detect the fingers of an operator who holds the region on the lower side (negative Z-axis side) (the region closer to the other corner) in the gripping portion 13R.

[0026] The detection electrodes 114-1 and 114-2 are provided integrally with a switch unit 100R provided on the spoke portion 14 of the steering wheel 12 in the vicinity of the connection region between the rim portion 13 and the spoke portion 14 of the steering wheel 12. As the detection electrodes 114-1 and 114-2, for example, a thin-film conductor such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or a metal film (for example, a composite material of silver, copper, aluminum, and molybdenum) is used.

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

[0028] As described above, the configuration of the switch unit 100R has been described. The configuration of the switch unit 100L is almost left-right symmetric with the configuration of the switch unit 100R and has 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 portion") on the upper side (positive Z-axis side) and the left side (negative X-axis side) of the lower case 102C, and is bent substantially at a right angle along the first corner C1. Thereby, in the switch unit 100L, the first detection electrode 114-1 can hover-detect the left hand finger of an operator existing close above (positive Z-axis direction) and to the left (negative X-axis direction) of the case 102. That is, in the switch unit 100L, the first detection electrode 114-1 can detect the finger of an operator who grips the upper region (region closer to one corner) in the gripping portion 13L (positive Z-axis side).

[0030] Also, in the switch unit 100L, the second detection electrode 114-2 is disposed at a second corner C2 (an example of "the other of a pair of corners facing the rim portion") on the lower side (negative Z-axis side) and the left side (negative X-axis side) of the lower case 102C, and is bent at a right angle along the second corner C2. Thereby, in the switch unit 100L, the second detection electrode 114-2 can hover-detect the left hand finger of an operator existing close below (negative Z-axis direction) and to the left (negative X-axis direction) of the case 102. That is, in the switch unit 100L, the second detection electrode 114-2 can detect the finger of an operator who grips the lower region (region closer to the other corner) in the gripping portion 13L (negative Z-axis side).

[0031] (Functional Configuration of Control Device 150) FIG. 7 is a diagram showing the functional configuration of a control device 150 included in a gripping detection device 30 according to an embodiment. The gripping detection device 30 according to an embodiment is a device capable of determining the presence or absence of the fingers of an operator's hand that grips the rim portion 13 (gripping portions 13L, 13R) of the steering wheel 12 based on the hover detection result by the electrostatic sensor unit 110 and outputting the determination result.

[0032] As shown in FIG. 7, a gripping detection device 30 according to an embodiment includes a control device 150 and detection electrodes 114-1 and 114-2 of each of switch units 100L and 100R.

[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 a first cable 21 and a connector 24.

[0034] Further, the control device 150 is 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] Further, the control device 150 is electrically connected to the rim core metal part 13A, the spoke core metal part 14A, a third cable 23, and a 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 a change in capacitance in 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 an AC voltage composed of a sine wave as a drive signal to the detection electrodes 114-1 and 114-2. Then, the detection electrodes 114-1 and 114-2 detect a change in the current value of the current flowing through the detection electrodes 114-1 and 114-2 as a change in capacitance.

[0038] In the vicinity of the gripping portion 13R, detection electrodes 114-1 and 114-2 provided in the switch unit 100R are provided to face the gripping portion 13R. For this reason, when the fingers of the operator's right hand grip the gripping portion 13R, the fingers of the operator's right hand are in proximity to the detection electrodes 114-1 and 114-2 of the switch unit 100R. Thereby, the detection electrodes 114-1 and 114-2 of the switch unit 100R are capacitively coupled to the fingers of the operator's right hand, and the current value of the current flowing through the detection electrodes 114-1 and 114-2 changes. Thereby, the detection electrodes 114-1 and 114-2 of the switch unit 100R can perform hover detection (non-contact detection) of the fingers of the operator's right hand. Note that since the detection electrodes 114-1 and 114-2 of the switch unit 100R have a shape bent at a substantially right angle as described above, with respect to a range of approximately ±30° in the gripping portion 13R with reference to the 90° position (positive X-axis side) of the rim portion 13, the fingers of the operator's right hand can be hover detected.

[0039] Also, in the vicinity of the gripping portion 13L, detection electrodes 114-1 and 114-2 provided in the switch unit 100L are provided to face the gripping portion 13L. For this reason, when the fingers of the operator's left hand grip the gripping portion 13L, the fingers of the operator's left hand are in proximity to the detection electrodes 114-1 and 114-2 of the switch unit 100L. Thereby, the detection electrodes 114-1 and 114-2 of the switch unit 100L are capacitively coupled to the fingers of the operator's left hand, and the current value of the current flowing through the detection electrodes 114-1 and 114-2 changes. Thereby, 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. Note that since the detection electrodes 114-1 and 114-2 of the switch unit 100L have a shape bent at a substantially right angle as described above, with respect to a range of approximately ±30° in the gripping portion 13L with reference to the 270° position (negative X-axis side) of the rim portion 13, the fingers of the operator's left hand can be hover detected.

[0040] The shield electrode control unit 152 generates an active shield signal and outputs the active shield signal to the rim core metal part 13A via the connector 24, the third cable 23, and the spoke core metal part 14A. Thereby, the shield electrode control unit 152 drives the rim core metal part 13A as an active shield electrode. The active shield signal is, for example, a signal 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 (that is, an AC voltage composed of a sine wave). When the rim core metal part 13A is driven as an active shield electrode, there is no increase in the capacitance value due to the presence of the rim core metal part 13A, and noise components applied from the rim core metal part 13A to the detection electrodes 114-1 and 114-2 can be removed. That is, the increase in capacitance and noise components due to the rim core metal part 13A can be removed from the capacitance detected by the detection electrodes 114-1 and 114-2 (see FIG. 8 described later).

[0041] Based on the change in capacitance at the detection electrodes 114-1 and 114-2 detected by the detection electrode control unit 151, the determination unit 153 determines the presence or absence of the fingers of the operator gripping the gripping parts 13L and 13R.

[0042] For example, when the difference value of the capacitance at the detection electrodes 114-1 and 114-2 provided in the switch unit 100R exceeds a predetermined threshold value th, the determination unit 153 determines that there are the fingers of the right hand of the operator gripping the gripping part 13R. Since there is the spoke part 14, the finger may exist only above (positive Z-axis direction) or below (negative Z-axis direction) the gripping part 13R. Therefore, when the measured value or the change amount of at least one of the detection electrodes 114-1 and 114-2 exceeds a predetermined threshold value, the determination unit 153 may determine that there are the fingers of the right hand of the operator.

[0043] Conversely, when the difference value of the capacitance at the detection electrodes 114-1 and 114-2 provided in the switch unit 100R is less than the predetermined threshold value th, the determination unit 153 determines that there are no fingers of the right hand of the operator gripping the gripping part 13R.

[0044] Further, for example, when the difference value of the capacitance in the detection electrodes 114-1 and 114-2 provided in the switch unit 100L exceeds a predetermined threshold value th, the determination unit 153 determines that there is a finger of the left hand of the operator who grips the gripping unit 13L.

[0045] Conversely, when the difference value of the capacitance in the detection electrodes 114-1 and 114-2 provided in the switch unit 100L is less than the predetermined threshold value th, the determination unit 153 determines that there is no finger of the left hand of the operator who grips the gripping unit 13L.

[0046] Note that a suitable value obtained in advance by actual machine tests, simulations, or the like is used as the threshold value th. As described above, since the control device 150 drives the rim core metal part 13A as an active shield electrode, the capacitance detected by the detection electrodes 114-1 and 114-2 is the capacitance of the rim core metal part 13A and the noise component from the rim core metal part 13A removed. Therefore, in the present embodiment, as the threshold value th, a value obtained by removing the capacitance of the rim core metal part 13A and the noise component from the rim core metal part 13A by the active shield electrode is used, so that the value is lower than that of the conventional configuration without using the active shield electrode.

[0047] The result output unit 154 outputs the determination result by the determination unit 153 (that is, the presence or absence of the fingers of the operator who grips the gripping units 13L and 13R) to the outside (for example, a device that executes processing according to the determination result by the determination unit 153).

[0048] Incidentally, the control processing in the control device 150 is realized by, for example, a computer (e.g., an IC (Integrated Circuit)) including a processor (e.g., a CPU), a storage medium (e.g., a ROM (Read Only Memory), a RAM (Random Access Memory), an SSD (Solid State Drive), 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 the storage medium in the control device 150.

[0049] (Comparative Example) FIGS. 8A and 8B are diagrams showing a comparative example of the capacitance detected by the gripping detection device 30 according to an embodiment. FIG. 8A is a diagram showing an example of the capacitance detected by a conventional gripping detection device having no active shield electrode. FIG. 8B is a diagram showing an example of the capacitance detected by the gripping detection device 30 according to an embodiment.

[0050] As shown in FIG. 8(a), in a conventional gripping detection device having no active shield electrode, since the capacitance due to the rim core metal part and the noise component from the rim core metal part are added to the detection electrode, the capacitance detected by the detection electrode includes the capacitance due to the rim core metal part and the noise component. By the way, the sensor has a detectable range in which the output value does not change and saturates even when a capacitance equal to or greater than a predetermined value is applied. Even if a threshold value th for determining that a finger has approached is set near the detectable range, in the case of including the capacitance due to the rim core metal part and the noise component in this way, even a slight increase in capacitance easily exceeds the threshold value th. Therefore, the conventional gripping detection device cannot accurately detect the finger of an operator gripping the rim part of the steering wheel. In other words, since the component of the capacitance accompanying the approach of the finger with respect to the unnecessary capacitance components (the capacitance due to the rim core metal part and the noise component from the rim core metal part) is small, it is difficult to improve the accuracy.

[0051] On the one hand, as shown in FIG. 8B, the gripping detection device 30 according to one embodiment can drive the rim core metal part 13A as an active shield electrode to remove the capacitance caused by the rim core metal part 13A and the noise components applied from the rim core metal part 13A to the detection electrodes 114-1 and 114-2. That is, the gripping detection device 30 according to one embodiment can remove the 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 gripping detection device 30 according to one embodiment can lower the threshold value th for finger detection determination, and due to the margin formed between the threshold value th for finger detection determination and the detectable range of the sensor, it can accurately detect the fingers of the operator gripping the rim portion 13 of the steering wheel 12. In other words, since the capacitance component associated with the approach of the finger is large with respect to the unnecessary capacitance components (the capacitance caused by the rim core metal part 13A and the noise component from the rim core metal part 13A), it is easy to improve the accuracy.

[0052] (An example of the circuit configuration included in the gripping detection device 30) FIGS. 9 to 11 are diagrams showing an example of the circuit configuration 30A included in the gripping detection device 30 according to one 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 metal 12A of the steering wheel 12 (that is, the rim core metal part 13A and the spoke core metal part 14A). In the circuit configuration 30A, the active shield signal generated by the signal source 32 is supplied to the core metal 12A via the voltage follower circuit 155. The voltage follower circuit 155 outputs the active shield signal generated by the shield electrode control unit 152 with sufficient voltage to the core metal 12A when connecting a control device 150 (shield electrode control unit 152), which is a signal source with a high output impedance, to a shield electrode (core metal 12A), which is a load with a low impedance. That is, by having the voltage follower circuit 155, the core metal 12A can be stably driven as an active shield electrode. As a result, in the circuit configuration 30A, the core metal 12A is driven as an active shield electrode by the active shield signal having a stable voltage, and the capacitance of the core metal 12A and the noise component from the core metal 12A are removed from the capacitance detected by the detection electrode 114.

[0054] Also, in the circuit configuration 30A shown in FIG. 9, the connection between the voltage follower circuit 155 and the spoke core metal part 14A is grounded via a channer diode 35.

[0055] Also, in the circuit configuration 30A shown in FIG. 10, the connection between the voltage follower circuit 155 and the spoke core metal part 14A is grounded via a varistor 36.

[0056] Also, in the circuit configuration 30A shown in FIG. 11, the connection between the voltage follower circuit 155 and the spoke core metal part 14A is grounded via a clamp diode configuration 37 composed of diodes 37A and 37B.

[0057] As a result, the gripping detection device 30 according to one embodiment can be driven as an active shield electrode while grounding the rim core metal part 13A to the ground, and can achieve a sufficient noise removal effect by the rim core metal part 13A and countermeasures against ESD (electrostatic discharge).

[0058] (Effect) As described above, the gripping detection device 30 according to one embodiment is provided on the spoke part 14 of the steering wheel 12, and includes an electrostatic sensor part 110 having a detection electrode 114 facing the rim part 13 of the steering wheel 12, a control device 150 for controlling the electrostatic sensor part 110, and a determination part 153 for determining the presence or absence of fingers gripping the rim part 13 based on the hover detection result by the electrostatic sensor part 110. The control device 150 uses the core metal of the steering wheel 12 as the shield electrode of the electrostatic sensor part 110.

[0059] As a result, the gripping detection device 30 according to one embodiment can provide a shield electrode without providing a separate member, and thus can suppress the influence of noise on the hover detection by the electrostatic sensor part 110 with an inexpensive configuration. Therefore, according to the gripping detection device 30 according to one embodiment, it is possible to highly accurately detect the fingers of the operator gripping the rim part 13 of the steering wheel 12.

[0060] Further, in the gripping 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 gripping detection device 30 according to one embodiment can enhance the hover detection performance by the electrostatic sensor part 110.

[0062] Also, in the gripping detection device 30 according to one embodiment, the shaft core of the steering wheel 12 is provided integrally with a rim shaft core portion 13A provided at the center of the rim portion 13 and a spoke shaft core portion 14A forming the spoke portion 14. The control device 150 is connected to the spoke shaft core portion 14A and drives the rim shaft core portion 13A as an active shield electrode via the spoke shaft core portion 14A.

[0063] Thereby, in the gripping detection device 30 according to one embodiment, since the control device 150 can be connected to the spoke shaft core portion 14A, the control device 150 can be easily connected to the shaft core of the steering wheel 12.

[0064] Also, in the gripping 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] Thereby, the gripping detection device 30 according to one embodiment can remove noise components from the active shield electrode to the electrostatic sensor unit 110. Therefore, the hover detection performance by the electrostatic sensor unit 110 can be enhanced.

[0066] Also, in the gripping detection device 30 according to one embodiment, the detection electrode 114 is provided in the vicinity of the connection region between the rim portion 13 and the spoke portion 14.

[0067] Thereby, the gripping detection device 30 according to one embodiment can accurately hover-detect the finger of an operator who grips the rim portion 13 in the vicinity of the connection region of the spoke portion 14 by the detection electrode 114.

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

[0069] As a result, the gripping detection device 30 according to one embodiment can install the detection electrode 114 with high space efficiency, and can accurately hover-detect the finger of the operator gripping the rim portion 13 by the detection electrode 114.

[0070] Further, in the gripping detection device 30 according to one embodiment, the switch unit 100 has a pair of corner portions C1 and C2 at positions facing the rim portion 13, and the electrostatic sensor unit 110 is bent and arranged along the first corner portion C1 of the pair of corner portions C1 and C2. The first detection electrode 114-1 and the second detection electrode 114-2 which are bent and arranged along the second corner portion C2 of the pair of corner portions.

[0071] As a result, the gripping detection device 30 according to one embodiment can individually and accurately hover-detect the finger gripping the region near the first corner portion C1 of the rim portion 13 and the finger gripping the region near the second corner portion C2 of the rim portion 13.

[0072] As described above, one embodiment of the present invention has been described in detail. However, the present invention is not limited to these embodiments, and various modifications or 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 that applies a signal synchronized with the drive signal applied to the detection electrode. However, the present invention is not limited to this, and the rim core metal portion 13A may be a so-called passive shield electrode having a constant voltage such as a ground voltage or a power supply voltage.

[0074] Further, 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. However, the present invention is not limited to this, and the rim core metal portion 13A may be driven as an active shield electrode without passing through 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, and incorporates the entire contents of the said application herein.

Explanation of Reference Numerals

[0076] 10 Steering device 12 Steering wheel 12A Shaft 13 Rim portion 13A Rim core portion 13B Coating portion 13L Gripping portion 13R Gripping 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 Gripping detection device 30A Circuit configuration 32 Signal source 35 Zener diode 36 Varistor 37 Clamp diode configuration 37A, 37B Diode 100, 100L, 100R Switch unit 100A Operation surface 102 Case 102A Surface 102B Upper case 102C Lower case 102Ca, 102Cb, 102Cc Side surface 104 Operation knob 110 Electrostatic sensor portion 112 Flexible substrate 112A First planar portion 112B Second planar portion 112C Third planar portion 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 Judgment unit 154 Result output unit 155 Voltage follower circuit AX Central axis th Threshold value

Claims

1. An electrostatic sensor unit provided in the spoke portion of a steering wheel and having a detection electrode facing the rim portion of the steering wheel; A control unit for controlling the electrostatic sensor unit; A determination unit for determining the presence or absence of fingers gripping the rim portion based on the hover detection result by the electrostatic sensor unit Comprising: The control unit: Uses the steering shaft of the steering wheel as the shield electrode of the electrostatic sensor unit; The detection electrode: Is provided integrally with a switch unit provided in the spoke portion of the steering wheel A gripping detection device characterized by this.

2. The control unit: Drives the steering shaft of the steering wheel as an active shield electrode The gripping detection device according to claim 1, characterized by this.

3. The steering shaft of the steering wheel: Has a rim shaft portion provided at the center of the rim portion and a spoke shaft portion forming the spoke portion integrally provided; The control unit: Is connected to the spoke shaft portion and drives the rim shaft portion as the active shield electrode via the spoke shaft portion The gripping detection device according to claim 2, characterized by this.

4. The control unit: Drives the active shield electrode with a drive signal having a waveform synchronized with the drive signal of the detection electrode The gripping detection device according to claim 2 or 3, characterized by this.

5. The detection electrode: Is provided near the connection region between the rim portion and the spoke portion The gripping detection device according to any one of claims 1 to 3, characterized by this.

6. The switch unit: Has a pair of corner portions at a position facing the rim portion; The electrostatic sensor unit: A first detection electrode which is the detection electrode bent and arranged along one of the pair of corner portions; And a second detection electrode which is the detection electrode bent and arranged along the other of the pair of corner portions The gripping detection device according to claim 1, characterized by this.

7. The steering wheel; And the gripping detection device according to any one of claims 1 to 3 A steering device characterized by comprising these.

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