JP2023173631A - Capacitive sensor and handle - Google Patents

Abstract

To provide a capacitive sensor which can maintain structural strength while suppressing maximum capacitance, and a steering wheel comprising the same.SOLUTION: A capacitive sensor 1 comprises a dielectric body 2, and paired electrodes 3, 4 that face each other in a prescribed direction with the dielectric body 2 sandwiched therebetween. The paired electrodes 3, 4 have non-electrode setting parts 6, 7. At least a part of one non-electrode setting part 6 is located at a position where the same does not overlap the other non-electrode setting part 7 in the prescribed direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a capacitive sensor having a pair of electrodes facing each other in a predetermined direction with a dielectric interposed therebetween, and a handle equipped with the same.

In recent years, there has been a demand for additional functions to be provided to the steering wheel of an automobile. For example, a steering wheel is known that includes a sensor for detecting that a driver grips a rim portion that is a grip portion. As this sensor, for example, a mat-like capacitance sensor embedded in the rim portion is used. Then, the detection result of whether or not the rim portion is gripped by the capacitance sensor is sent to the on-board control unit (ECU), and depending on the detection result, the on-board control unit performs various actions such as turning the heater on and off or switching automatic operation. Appropriate control is performed (for example, see Patent Document 1).

JP 2021-127059 (pages 4-10, Figure 1-3)

As rims have become larger in recent years, or when used on large-diameter rims, the electrode area of capacitive sensors has increased, resulting in an increase in the maximum capacitance of capacitive sensors. It is assumed that the amount of electricity (electrical energy) stored in the capacitor of the capacitive sensor exceeds the electrical energy that the on-vehicle control device can withstand. Therefore, it is required to suppress the maximum capacitance of the capacitance sensor.

One possible countermeasure is to reduce the area of the electrode, but if the outer shape of the electrode is simply reduced, the range that can be detected by the capacitance sensor becomes narrower. Therefore, in order to reduce the area of the electrode while maintaining the outer shape of the electrode, it is conceivable to remove a portion of the electrode (remove the thickness).

However, there is a physical limit to thinning the electrode; for example, if it is desired to reduce the maximum capacitance by half, it is necessary to thin out half the area of the electrode. Such thinning reduces the strength of the electrode, which may cause damage to the electrode during manufacture or use, raising concerns about strength and workability (productivity).

The present invention was made in view of the above points, and an object of the present invention is to provide a capacitance sensor that can maintain structural strength while suppressing maximum capacitance, and a handle equipped with the same. do.

The capacitance sensor according to claim 1 includes a dielectric and a pair of electrodes facing each other in a predetermined direction with the dielectric interposed therebetween, and each of the pair of electrodes has an electrode non-setting portion. , at least a portion of one of the electrode non-setting portions is arranged at a position that does not overlap the other electrode non-setting portion in the predetermined direction.

A capacitance sensor according to a second aspect of the invention is the capacitance sensor according to the first aspect, in which the electrode non-setting portion is a hole formed in the electrode.

A capacitance sensor according to a third aspect of the invention is the capacitance sensor according to the second aspect, in which the electrode non-setting portion has a circular shape.

A handle according to a fourth aspect of the present invention includes a grip section having a capacitance sensor according to any one of claims 1 to 3, and a detection section that detects a grip state of the grip section based on a detection result of the capacitance sensor. It is equipped with the following.

According to the capacitance sensor according to claim 1, it is possible to set a large area of a portion that does not function as a sensor without forming an excessive number of non-electrode portions on each electrode. This makes it possible to suppress the maximum capacitance of the capacitance sensor while suppressing an excessive decrease in the strength of the electrode, thereby maintaining structural strength.

According to the capacitance sensor according to the second aspect, in addition to the effect of the capacitance sensor according to the first aspect, the electrode non-setting portion can be easily set.

According to the capacitance sensor according to claim 3, in addition to the effect of the capacitance sensor according to claim 2, the area of the electrode non-setting portion is increased while suppressing the peripheral length of the electrode non-setting portion, In addition, since the electrode non-setting portion does not have a corner, local stress concentration is less likely to occur on the electrode, and damage to the electrode from the electrode non-setting portion can be suppressed.

According to the handle according to claim 4, the detection unit can easily detect the gripping state of the gripping portion according to the detection result of the capacitance sensor. Even when used in a gripping part, the maximum capacitance of a capacitive sensor is suppressed, making it difficult for the amount of electricity stored in the capacitive sensor to exceed the electrical energy that the detecting part can withstand, and reducing static The electrodes are less likely to be damaged when the capacitance sensor is attached to the grip or used, and good strength and workability can be obtained.

(a) is a plan view showing a capacitance sensor according to the first embodiment of the present invention, and (b) is a sectional view taken along line AA in (a). (a) is a plan view showing one electrode of the same capacitance sensor, and (b) is a plan view showing the other electrode of the same capacitance sensor. (a) is a front view showing a handle equipped with the same capacitance sensor as above, and (b) is a sectional view taken along the line BB in (a). (a) is a plan view showing a capacitance sensor according to a second embodiment of the present invention, and (b) is a sectional view taken along the line CC in (a). (a) is a plan view showing one electrode of a capacitance sensor according to the third embodiment of the present invention, (b) is a plan view showing the other electrode of the capacitance sensor according to the above, and (c) is the same as above. FIG. 2 is a plan view showing a capacitance sensor. It is a front view showing a handle provided with a capacitance sensor same as the above.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1(a) and 1(b), 1 is a capacitance sensor. The capacitance sensor 1 is a proximity sensor that detects the proximity of an object based on a change in capacitance.

The capacitance sensor 1 includes a dielectric 2 and electrodes 3 and 4 on one side and the other side sandwiching the dielectric 2, forming a capacitor. The capacitive sensor 1 is formed into a thin sheet.

The dielectric 2 is formed, for example, in a rectangular shape. Any dielectric material 2 may be used.

The electrodes 3 and 4 have the same or substantially the same external shape as the dielectric 2. That is, the electrodes 3 and 4 have a rectangular outer shape. The electrodes 3 and 4 are formed into thin flat plates made of conductive metal or the like. The electrodes 3 and 4 are opposed to each other in a predetermined direction (direction shown by arrow X in the figure) with the dielectric 2 in between. A DC power supply section is connected between the electrodes 3 and 4. That is, one of the electrodes 3 and 4 is connected to the plus side of the DC power supply, and the other is connected to the minus side of the DC power supply.

Here, the maximum capacitance C of the capacitance sensor 1 is C=εS/d [ F]. Further, the amount of electricity (electrical energy) Q stored in the capacitance sensor 1 is expressed as Q=CV[C], where V is the potential difference between the electrodes 3 and 4. Therefore, the maximum capacitance C of the capacitance sensor 1 is proportional to the area of the mutually opposing portions of the electrodes 3 and 4, and the amount of electricity stored in the capacitance sensor 1 is proportional to the maximum capacitance. In this embodiment, by forming one and the other non-electrode setting portions 6, 7 on the electrodes 3, 4, which do not function as electrodes, the effective action area of the electrodes 3, 4 is reduced, thereby increasing the capacitance. The aim is to reduce the maximum capacitance of the sensor 1, that is, the amount of electricity that can be stored.

The electrode non-setting parts 6 and 7 are holes formed by penetrating (removing) the electrodes 3 and 4, for example. Preferably, the electrode non-setting parts 6 and 7 are formed in a circular shape. In this embodiment, the electrode non-setting portion 6 and the electrode non-setting portion 7 have the same or substantially the same shape, that is, circular shapes having the same or substantially the same diameter. A plurality of electrode non-setting portions 6 and 7 are formed in each of the electrodes 3 and 4, respectively. The plurality of electrode non-setting portions 6 may have the same shape or may have mutually different shapes. Similarly, the plurality of electrode non-setting portions 7 may have the same shape or may have mutually different shapes.

In this embodiment, as shown in FIG. 2(a), the electrode non-setting portions 6 are arranged apart from each other in the electrode 3. In the illustrated example, the electrode non-setting portions 6 are arranged in a staggered manner in the electrode 3. Preferably, the electrode non-setting portions 6 are arranged at equal or approximately equal intervals. The space between the non-electrode setting portions 6 is an electrode setting portion 8 that functions as an electrode.

Similarly, as shown in FIG. 2(b), the electrode non-setting portions 7 are arranged apart from each other in the electrode 4. In the illustrated example, the electrode non-setting portions 7 are arranged in a staggered manner on the electrode 4. Preferably, the electrode non-setting portions 7 are arranged at equal or approximately equal intervals. Between the non-electrode setting portions 7 is an electrode setting portion 9 that functions as an electrode.

As shown in FIGS. 1(a) and 1(b), in the present embodiment, the electrode non-setting parts 6 and 7 are such that at least a part of one electrode non-setting part 6 is connected to the other electrode non-setting part 6. It is arranged at a position that does not overlap part 7 in a predetermined direction (direction shown by arrow X), that is, at a shifted position. That is, when viewed from a predetermined direction, the electrode non-setting portion 6 of the electrode 3 is located at least partially opposite the electrode setting portion 9 of the electrode 4, and the electrode non-setting portion 7 of the electrode 4 is located opposite the electrode setting portion 9 of the electrode 3. At least a portion thereof is located opposite to the setting section 8. In the illustrated example, each electrode non-setting portion 6 of the electrode 3 is located entirely opposite the electrode setting portion 9 of the electrode 4, and each electrode non-setting portion 7 of the electrode 4 is located opposite to the electrode setting portion 9 of the electrode 3. The entire device is located opposite to the setting section 8. Therefore, the non-electrode setting portion 6 of the electrode 3 and the non-electrode setting portion 7 of the electrode 4 are located at positions that do not face each other in the predetermined direction.

As shown in FIG. 1(a), electrode non-setting parts 7, 7 are located between electrode non-setting parts 6, 6 when viewed from a predetermined direction. That is, the electrode non-setting parts 6, 6 are located between the electrode non-setting parts 7, 7. In the illustrated example, the electrode non-setting portions 6 and the electrode non-setting portions 7 are arranged alternately along a predetermined line L. In the case of this embodiment, the electrode non-setting portions 6 and the electrode non-setting portions 7 are arranged alternately on a predetermined line L that is inclined with respect to a direction parallel to the outer edges of the electrodes 3 and 4. Further, the distance between the electrode non-setting portions 6, 6 arranged on the line L is the same or approximately the same as the outer diameter of the electrode non-setting portion 7, respectively. Similarly, the distance between the electrode non-setting portions 7, 7 arranged on the line L is the same or approximately the same as the outer diameter of the electrode non-setting portion 6, respectively. Therefore, on the line L, when viewed from a predetermined direction, the electrode non-setting portion 6 and the electrode non-setting portion 7 are located adjacent to each other without or almost without a gap, and are used as a capacitance sensor 1 (capacitor). A non-acting portion 11 (shown by a two-dot chain line in FIGS. 1(a) and 1(b)) that does not act is formed in an elongated strip shape. In this embodiment, a plurality of these non-acting portions 11 are arranged in a line and spaced apart from each other in a direction perpendicular to a predetermined line L.

In this embodiment, the capacitance sensor 1 is a vehicle sensor member also called a steering mat. For example, the capacitance sensor 1 is used in a steering wheel 15, which is a steering wheel shown in FIGS. 3(a) and 3(b).

The steering wheel 15 is used for steering a vehicle such as an automobile. The steering wheel 15 has a core metal 20 that is a handle body. The core metal 20 is made of metal, such as an alloy such as aluminum or magnesium. The core metal 20 includes a boss core metal part 21 having a substantially cylindrical boss with a serration structure that meshes with the steering shaft, and a spoke core metal part 22 is continuously and integrally formed from the boss core metal part 21. At the same time, a rim core metal part 23 as a grip part core metal is fixed to the spoke core metal part 22 by welding or the like.

A module 25 such as an air bag device is arranged in the boss core part 21 . The boss portion 27 is constituted by the boss core metal portion 21 and the module 25. The back side of the boss portion 27 is covered with a cover body also called a back cover, lower cover, or body cover.

The spoke core metal parts 22 are provided radially from the boss core metal part 21. At least a portion of these spoke core metal parts 22 constitute spoke parts 28 that extend radially from the boss part 27 . Note that the spoke portions 28 do not necessarily include the spoke core metal portion 22, and some spoke portions 28 may be configured with a finisher, a cover body, or the like without having the spoke core metal portion 22. In this embodiment, two spoke core metal parts 22 are set on the left and right sides of the boss core metal part 21, and one is set at the lower part. Although a three-spoke structure is shown in which one spoke section 28 is provided, the number of spoke sections 28 is not limited to this, and the number of spoke sections 28 may be two or four or more.

The rim core metal part 23 is formed in an annular or arcuate shape that extends over the entire circumference. A portion extending from the end of the spoke core metal portion 22 to the rim core metal portion 23 is covered with a covering portion 30. Furthermore, a skin body 31 is disposed on the surface of the covering portion 30 as required. The spoke core part 22, the covering part 30, and the skin body 31 constitute a rim part (grip part) 32 that is a grip part that is gripped and operated by a vehicle occupant (driver). The rim portion 32 is formed in an annular shape or a circular arc shape that extends over the entire circumference depending on the shape of the rim core metal portion 23.

The covering portion 30 is a resin layer made of, for example, synthetic resin. The covering portion 30 is made of, for example, finely foamed soft foamed polyurethane resin.

In this embodiment, the capacitance sensor 1 is arranged in the covering part 30. The capacitance sensor 1 may be embedded in the covering part 30 or may be wrapped around the surface of the covering part 30. The capacitance sensor 1 is supported, for example, on a sheet member that is a carrier. The capacitance sensor 1 can be placed at any position on the rim portion 32. In this embodiment, as shown in FIG. 3(b), the capacitance sensor 1 is arranged along the meridian direction, the cross-sectional circumferential direction, or the small diameter direction of the rim portion 32 so as to wrap around the rim core metal portion 23. The rim portion 32 is curved and arranged to extend in the latitude (longitude) direction, the circumferential direction in front view, or the large diameter direction of the rim portion 32 . That is, the electrodes 3 and 4 (FIG. 1(b)) are formed longitudinally in the meridian direction of the rim portion 32. As an example, in the capacitive sensor 1, the electrode 3 (FIG. 1(b)) is arranged on the outside of the rim portion 32, and the electrode 4 (FIG. 1(b)) is arranged on the inside of the rim portion 32, that is, on the side closer to the core metal 20. be done. Wiring electrically connected to each electrode 3, 4 (FIG. 1(a)) of the capacitance sensor 1 is arranged in the spoke part 28, and is electrically connected to an on-vehicle control device 35 such as an ECU located on the vehicle body side. connected. The vehicle-mounted control device 35 is a detection unit that detects the gripping state of the rim portion 32, that is, whether or not the rim portion 32 is gripped, based on the detection result of the capacitance sensor 1.

The capacitance sensor 1 determines the gripping state of the rim portion 32 in the on-vehicle control device 35 based on the magnitude of the composite capacitance that changes depending on whether the occupant (driver) is in contact with the rim portion 32 or not. Detected.

When the passenger (driver) grips the rim portion 32, the hand of the passenger (driver) forms a capacitor between the electrode 3 on the outside of the rim portion 32 and the ground, and a predetermined capacitance C1 is generated. Further, when the passenger (driver) does not grip the rim portion 32, a small parasitic capacitance (stray capacitance) C2 is generated between the electrode 3 and the ground. Therefore, in the capacitance sensor 1, the combined capacitance of the maximum capacitance C, the capacitance C1 generated when the passenger (driver) grips the rim portion 32, and the maximum capacitance The combined capacitance of C and the parasitic capacitance C2 when the passenger (driver) is not gripping the rim portion 32 is significantly different. Therefore, the vehicle-mounted control device 35 can detect the gripping state of the rim portion 32 according to the change in the combined capacitance.

At this time, in this embodiment, at least a part of the electrode non-setting parts 6 and 7 set in the pair of electrodes 3 and 4 are arranged in a position where they do not overlap in a predetermined direction, so that each electrode 3 and 4 It becomes possible to set a large area of the non-operating portion 11 that does not function as a sensor without forming excessive electrode non-setting portions 6 and 7. Therefore, it is possible to suppress the maximum capacitance of the capacitance sensor 1 according to the area of the non-acting part 11, suppress an excessive decrease in the strength of the electrodes 3 and 4, and maintain the structural strength. It becomes possible.

Moreover, since the area of the non-active portion 11 can be increased without reducing the external dimensions of the electrodes 3 and 4, the outer edge of the detection range by the capacitance sensor 1 does not become smaller.

For example, by forming holes in the electrodes 3 and 4 as the electrode non-setting parts 6 and 7, the electrode non-setting parts 6 and 7 can be easily set.

At this time, by making the electrode non-setting parts 6 and 7 circular holes, the area of the electrode non-setting parts 6 and 7 can be increased while suppressing the peripheral length of the electrode non-setting parts 6 and 7. Since the electrode non-setting portions 6 and 7 do not have corners, local stress concentration is less likely to occur on the electrodes 3 and 4, and damage to the electrodes 3 and 4 from the electrode non-setting portions 6 and 7 can be suppressed.

By using this capacitance sensor 1 in the steering wheel 15, the in-vehicle control device 35 can easily detect the gripping state of the rim portion 32 according to the detection result of the capacitance sensor 1. 32 is enlarged (has a large cross-sectional diameter) or is used for a large-diameter rim portion 32, the maximum capacitance of the capacitance sensor 1 is suppressed, so the capacitance sensor 1 The amount of electricity (electrical energy) stored in the capacitor can be prevented from exceeding the electrical energy that the on-vehicle control device 35 can withstand, and the electrodes 3 and 4 can be It is hard to break and can provide good strength and workability.

Note that the electrode non-setting portions 6 and 7 of the electrodes 3 and 4 of the capacitance sensor 1 may at least partially overlap each other when viewed from a predetermined direction. For example, as in the second embodiment shown in FIGS. 4(a) and 4(b), the electrode non-setting portion 6 and the electrode non-setting portion 7 are partially overlapped when viewed from a predetermined direction. By setting the position, the non-acting portions 11 may not be continuous on the predetermined line L. In this case, the acting part 38 on which the capacitance sensor 1 (capacitor) acts is arranged between the non-acting parts 11, 11. Therefore, the maximum capacitance of the capacitance sensor 1 can be set larger than that in the first embodiment. In this way, the area of the non-working part 11, that is, the area of the electrodes 3 and 4 that can act as an electrode, can be adjusted according to the degree of overlap between the non-electrode setting parts 6 and 7. The maximum capacitance of the capacitive sensor 1 can be adjusted.

For example, as in the third embodiment shown in FIGS. 5 and 6, if you want to set a non-detection range A (FIG. 6) that extends in the latitude direction on the front side of the rim portion 32, As shown in a) to FIG. 5(c), the electrode non-setting parts 6 and 7 are arranged along the long sides (side edges) of the electrodes 3 and 4, and As seen, by arranging the non-electrode setting parts 6 and 7 of the electrodes 3 and 4 so that they are alternately positioned along the long sides (side edges) of the electrodes 3 and 4, the non-working part 11 The capacitive sensor 1 is arranged on the rim part 32 so that the capacitance sensor 1 is continuous in the latitude direction on the front side of the rim part 32. Thereby, the above-mentioned non-detection range A can be set as a range in which the capacitance sensor 1 does not act. In this way, by setting the formation positions of the electrode non-setting parts 6 and 7 in the electrodes 3 and 4, it becomes possible to arbitrarily set the range to be detected by the capacitance sensor 1 in the rim part 32.

In each of the embodiments described above, the capacitance sensor 1 can be used for any other purpose in addition to being used as a part of a vehicle detection device applied to a vehicle steering wheel 15.

INDUSTRIAL APPLICATION This invention can be suitably used, for example as a capacitance sensor which detects the grip state of the rim part of a steering wheel for vehicles, and a steering wheel equipped with the same.

1 Capacitance sensor 2 Dielectric 3, 4 Electrode 6, 7 Non-electrode setting part 15 Steering wheel which is a handle 32 Rim part which is a grip part 35 In-vehicle control device which is a detection part

Claims (4)

dielectric and
A pair of electrodes facing each other in a predetermined direction with the dielectric interposed therebetween,
The paired electrodes each have an electrode non-setting portion,
A capacitance sensor, wherein at least a part of one of the electrode non-setting portions is arranged at a position that does not overlap the other electrode non-setting portion in the predetermined direction. The capacitance sensor according to claim 1, wherein the electrode non-setting portion is a hole formed in the electrode. The capacitance sensor according to claim 2, wherein the electrode non-setting portion has a circular shape. A gripping portion having the capacitance sensor according to any one of claims 1 to 3;
a detection unit that detects a gripping state of the gripper based on a detection result of the capacitance sensor;
A handle comprising:

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