JP2007198892A - Impact detecting sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact detecting sensor which surely avoids any incorrect judgment, without the need for any tuning operation. <P>SOLUTION: The impact detecting sensor A1, in which a pseudo capacitor is made up of a pair of opposing polar plates to detect an impact by acquiring a change in capacitance when causing current to flow in the pair of polar plates, comprises: a spherical deforming polar plate 2 (deforming plate) which is formed so as to be deformable under an impact force; a spherical fixed polar plate 1 (fixed plate) which is disposed opposite to the spherical deforming polar plate 2; and an impact sensing circuit 6 (capacitance change detecting means) which detects the change in capacitance of the polar plates 1, 2 whose capacitance changes due to the deformation of the spherical deforming polar plate 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field of an impact detection sensor that has a pair of opposing electrode plates to constitute a pseudo capacitor and detects an impact by detecting a change in capacitance when electricity is passed through the pair of electrode plates. Belonging to.

  As a conventional impact detection sensor, there is a G sensor (acceleration sensor) that is becoming more reliable as technology is improved. This is used to detect a collision in the event of an automobile accident and deploy an airbag. There are several types of sensors that detect this collision. Typical examples include a pendulum type in which the contact point inside the sensor is switched on by an impact, or a dielectric that exists between a pair of electrode plates moves by an impact. There is a capacitance type that reads changes.

Examples of the capacitance type G sensor include those using a semiconductor capacitance type collision acceleration detector as a collision detection device of an airbag system (for example, see Patent Document 1), and included in a predetermined plane. What detects the magnitude | size of the acceleration which faced the direction as an electrical signal based on the fluctuation | variation of an electrostatic capacitance is known (for example, refer patent document 2).
JP-A-4-292242 Japanese Patent Laid-Open No. 9-119943

However, in a conventional pendulum type or electrostatic capacitance type G sensor, when a certain impact or more is applied to the vehicle, it is determined that the mass body (weight body, movable electrode, etc.) moves more than a predetermined amount as a collision. . Therefore, for example, if the impact is applied to the G sensor even in a non-collision scene such as when a part of the vehicle touches the ground or rides on a curb while driving on a rough road, it is judged as a collision and air There is a possibility of expanding the back.
On the other hand, the erroneous determination is minimized by tuning the G sensor, but it is inefficient because it requires a very large number of man-hours. Further, depending on the vehicle model, the input G changes even in a collision at the same speed, and thus there is a problem that tuning must be performed for each vehicle model.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide an impact detection sensor that does not require tuning and can reliably avoid erroneous collision determination.

In order to achieve the above object, in the present invention, a pseudo capacitor is formed by having a pair of opposing plates, and an impact is detected by capturing a change in capacitance when electricity is passed through the pair of plates. In the impact detection sensor that
A deformed electrode plate formed to be deformable by an impact force;
A fixed electrode plate disposed opposite to the deformed electrode plate;
A capacitance change detecting means for detecting a change in capacitance between the two electrode plates, which is changed by deformation of the deformed electrode plate;
It is provided with.

Therefore, in the impact detection sensor of the present invention, deformation is performed in a state where electricity is passed through a pair of electrode plates composed of a fixed electrode plate and a deformed electrode plate that are concentrically fixed while being kept at equal intervals. When an impact force is applied to the electrode plate and its shape is deformed, an input of the impact force is detected by detecting a change in capacitance due to the deformation.
That is, in the case of a conventional G sensor that determines that a collision occurs when the mass moves more than a predetermined amount, for example, even when the vehicle does not collide, such as when a part of the vehicle touches the ground or rides on a curb while traveling on a rough road When the impact is applied to the G sensor, there is a possibility that it is erroneously determined as a collision. In order to minimize this erroneous determination, tuning that requires a very large man-hour must be performed for each vehicle model to be applied.
On the other hand, in the present invention, unless the deformed electrode plate is deformed by the directly applied impact force, it is not determined that the collision has occurred, so that it is not only necessary to perform the tuning operation, but also deformed even if high G occurs. Even if there is a bad road running or curb ride that does not lead to deformation of the electrode plate, the impact is not erroneously determined.
As a result, it is possible to reliably avoid erroneous collision determination without requiring tuning.

  Hereinafter, the best mode for carrying out the impact detection sensor of the present invention will be described based on Examples 1 to 4 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall perspective view illustrating an impact detection sensor according to a first embodiment, FIG. 2 is a circuit configuration diagram illustrating an example of an impact detection circuit and an impact determination circuit of the impact detection sensor according to the first embodiment, and FIG. It is a figure which shows an example of the vehicle carrying the airbag system to which the detection sensor was applied.

  The impact detection sensor of the present invention has a pair of opposing electrode plates to form a pseudo capacitor, and detects an impact by capturing a change in capacitance when electricity is passed through the pair of electrode plates. For this reason, the pair of electrode plates are configured by a fixed electrode plate and a deformed electrode plate having similar shapes fixed concentrically while maintaining an equal interval, and the deformed electrode plate is electrostatically deformed even when partly deformed by an impact force. The shape was set to change the capacity. A specific configuration will be described below.

  In the impact detection sensor A1 according to the first embodiment, the fixed plate and the deformed plate are set inside the sphere fixed plate 1 set inside and outside the sphere fixed plate 1 as shown in FIG. A spherical deformation electrode plate 2 covering the entire outer periphery of the spherical fixed electrode plate 1. An insulating support member 3 is set between the spherical fixed electrode plate 1 and the spherical deformed electrode plate 2 to keep the distance between the two electrode plates 1 and 2 at equal intervals.

The spherical deformation electrode plate 2 is formed of a thin metal plate having conductivity that is easily deformed by an external force applied thereto.
As shown in FIG. 1, the insulating support member 3 is arranged on an axis passing through a common center point O of the spherical fixed electrode plate 1 and the spherical deformed electrode plate 2, and the insulating support member 3 is a low-strength material. When formed by the above, it is possible to detect an impact from any three-dimensional direction with the single impact detection sensor A1. Further, when the insulating support member 3 is formed of a high strength material, the detection accuracy between the member setting axis direction and the member setting axis orthogonal direction is differentiated, the impact sensitivity in the member setting axis direction is low, and the member setting axis orthogonal The impact sensitivity changes depending on the direction so that the impact sensitivity of the direction becomes higher.
In addition, a dielectric is filled between the spherical fixed electrode plate 1 and the spherical deformed electrode plate 2. Here, the “dielectric material” is a substance that polarizes when in an electric field and mediates the electrostatic induction action, and for example, an insulating substance such as air, paraffin, paper, rubber, insulating oil, glass, plastic, etc. Say.

  In the impact detection sensor A1 of Example 1, as shown in FIG. 2, a power source 4 for applying an alternating current to the spherical fixed plate 1 and the spherical deformed polar plate 2, and the spherical fixed plate 1 and the spherical deformed polar plate. 2 is connected to an impact detection circuit 6 having a voltage meter 5 for measuring the voltage applied to the voltage detector 2, and the voltage waveform of the power source 4 in the impact detection circuit 6 is compared with the voltage waveform from the voltmeter 5. An impact determination circuit 7 is provided for determining that the sensor body has received an impact when the voltmeter waveform deviates from the phase delayed by 90 degrees with respect to the power supply voltage waveform or when the peak voltage changes.

That is, an alternating current is applied from the power source 4 to the impact detection sensor A1, and the voltage applied to the impact detection sensor A1 is measured. When no impact is input, the phase of the impact detection sensor A1, which is a pseudo capacitor, is delayed by 90 degrees with respect to the power supply 4. When the phase of this voltage is shifted or the peak voltage is changed, it is determined that the sensor body has received an impact. The reason why this occurs is that an impact is applied to the spherically deformed electrode plate 2 and a part thereof is recessed, whereby the distance between the electrode plates is changed.
The reason why the voltage changes due to the depression of the spherical deformation electrode plate 2 can be explained by the following equation.
V = (1 / C) ∫Idt = (S / εd) ∫Idt (1)
Where V: voltage between electrode plates, C: capacitance, I: alternating current, S: electrode plate area, ε: dielectric constant, d: electrode plate area.
As is clear from the above equation (1), the capacitance C also changes due to the change in the electrode plate area d, and the voltage V between the electrodes changes accordingly, so that the impact can be detected. .

  The impact detection sensor A1 of Example 1 was applied as a collision detection means of a vehicle airbag system, and was set at a position close to the outside of the vehicle. This is because the possibility that the impact detection sensor A1 is deformed is reduced unless the vehicle body is largely deformed. For example, as shown in FIG. 3, the impact detection sensor A1 is set at the left and right corner positions in front of the vehicle.

Next, the operation will be described.
[Background technology]
In recent years, automobiles equipped with an occupant protection device (such as an air bag or a pre-crash seat belt) that safely protects an occupant in the event of a collision are rapidly spreading. For example, as for the airbag system, automobiles equipped with a driver's seat airbag, a passenger seat airbag, a right side airbag, and a left side airbag are already on the market. In order to effectively deploy multiple airbags in this airbag system, high-precision collision detection is required not only for frontal collisions but also for collisions from all directions such as offset collisions and collisions from the side of the vehicle. Has been.

  On the other hand, in a conventional pendulum type or electrostatic capacitance type G sensor, when a certain level of impact is applied to the vehicle, if the mass body (weight body, movable electrode, etc.) moves more than a predetermined amount, judge. Therefore, for example, if the impact is applied to the G sensor even in a non-collision scene such as when a part of the vehicle touches the ground or rides on a curb while driving on a rough road, it is judged as a collision and air There is a possibility of expanding the back. In order to minimize this erroneous determination, tuning of the G sensor is necessary, but the sensor tuning is inefficient because it requires a very large number of man-hours. In addition, depending on the vehicle type, the input G changes even in a collision at the same speed, so tuning must be performed for each vehicle type.

  Furthermore, the direction that can be detected by the G sensor that detects the collision by using the movement of the mass body is limited to two directions (one direction + the direction of 180 degree inversion). For example, an impact from any direction is detected. For this purpose, it is necessary to install a number of G sensors corresponding to the desired direction. However, since the G sensor is expensive, it is difficult to arrange it in large quantities.

[About impact detection]
On the other hand, in the impact detection sensor A1 according to the first embodiment, the pair of electrode plates are configured by the spherical fixed electrode plate 1 and the spherical deformed electrode plate 2 that are disposed to face each other, so that tuning is not required and erroneous collision determination is performed. I was able to avoid it reliably.

That is, an alternating current is applied from the power source 4 of the impact detection circuit 6 to the spherical fixed electrode plate 1 and the spherical deformation electrode plate 2 of the impact detection sensor A1, and the voltage applied to the impact detection sensor A1 is the impact detection circuit 6. The voltmeter 5 is used for measurement. When no impact is input, the phase measured by the voltmeter 5 of the impact detection sensor A1, which is a pseudo capacitor, is delayed by 90 degrees with respect to the AC phase of the power supply 4.
In this state, when the spherical deformation electrode plate 2 is dented by an impact, the distance between the spherical fixed electrode plate 1 and the spherical deformation electrode plate 2 kept at a constant interval changes, and the power supply AC phase and the voltmeter measurement phase shift. Or the peak voltage changes. Therefore, it is possible to detect that the sensor body has received an impact by capturing the phase shift and the change in the peak voltage by the impact determination circuit 7.

  As described above, in the impact detection sensor A1 according to the first embodiment, unless the spherical deformation electrode plate 2 is deformed, it is not determined that the collision has occurred. Even if there is a bad road running or curb ride that does not lead to deformation of the deformed electrode plate, the impact is not misjudged.

In the impact detection sensor A1 according to the first embodiment, the fixed plate and the deformed plate are set inside the sphere fixed plate 1 and the outside of the sphere fixed plate 1. An insulating support member 3 that keeps the distance between the two electrode plates 1 and 2 at an equal interval between the spherical fixed electrode plate 1 and the spherical deformed electrode plate 2. did.
For this reason, since the number of parts is small and the structure is simple, manufacture is easy, and the impact detection sensor A1 can be manufactured at low cost.
Further, by forming the insulating support member 3 that keeps the distance between the bipolar plates 1 and 2 at an equal interval from a low-strength material, the impact detection sensor A1 can detect an impact from any three-dimensional direction.
Furthermore, by forming the insulating support member 3 that keeps the distance between the bipolar plates 1 and 2 at an equal interval with a high-strength material, the detection accuracy between the member setting axis direction and the member setting axis orthogonal direction is differentiated, and the member setting axis The impact sensitivity can be changed for each direction such that the impact sensitivity in the direction is low and the impact sensitivity in the direction orthogonal to the member setting axis is high.
It should be noted that changing the impact sensitivity depending on the direction makes it difficult to deform a part of the spherical deformation electrode plate 2 thickly, or defines the interior of the bipolar plates 1 and 2 in a plurality of chambers to fill the dielectric. It is also possible by changing part of the body material.

In the impact detection sensor A1 of the first embodiment, a power supply 4 for applying an alternating current to the spherical fixed plate 1 and the spherical deformed polar plate 2, and a voltage applied to the spherical fixed plate 1 and the spherical deformed polar plate 2 are used. An impact detection circuit 6 having a voltmeter 5 to be measured, and the voltage waveform of the power supply 4 in the impact detection circuit 6 is compared with the voltage waveform from the voltmeter 5, and the voltage is compared with the power supply voltage waveform. An impact judgment circuit 7 is provided for judging that the sensor body has received an impact when the measured waveform deviates from the phase delayed by 90 degrees or the peak voltage changes.
For this reason, it is possible to accurately detect that the sensor body has received an impact by the simple impact detection circuit 6 and the impact determination circuit 7 that can easily detect a phase shift or a change in peak voltage. .

[Installation location when the vehicle is applied]
The impact detection sensor A1 according to the first embodiment does not determine that a collision has occurred unless the surrounding parts collide with the sensor body and are deformed. For example, the closer to the outside of the vehicle, such as near the metal body of the vehicle, the lighter collision (small dent) can be detected if the spherical deformation electrode plate 2 of the impact detection sensor A1 is deformed thereby. Conversely, if installed near the center of the engine compartment (= engine room), the impact detection sensor A1 will be less likely to be deformed unless the car body is deformed that much. Minor collisions will not be detected. Therefore, if the installation location of the impact detection sensor A1 is changed depending on the form of the collision to be detected, it is possible to determine the collision more efficiently.

FIG. 3 shows a comparison of collision detection ranges when the sensor of the prior art is replaced with the impact detection sensor A1 of the first embodiment. In this case, it can be seen that the impact detection sensor A1 of the first embodiment has a detectable range that is nearly double that detectable by the conventional sensor.
When using the sensor in the method of FIG. 3, it is considered most effective to install the spherical impact detection sensor A1 of the first embodiment or the hemispherical impact detection sensor A4 of the fourth embodiment. It is done.

As described above, the impact detection sensor A1 of Example 1 was applied as a collision detection means of a vehicle airbag system, and was set at a position close to the outside of the vehicle.
For this reason, even during a mild collision that deforms the vehicle body to a small extent, the spherical deformation electrode plate 2 of the impact detection sensor A1 is recessed and deformed with the deformation of the vehicle body, and the collision can be detected with high accuracy.

In the impact detection sensor A1 of Example 1, the set position on the vehicle was set to the left and right corner positions in front of the vehicle.
For this reason, it is possible to detect a vehicle collision over a wide range that is nearly double as compared with a range that can be detected by a sensor of the prior art. In other words, if the same collision range is to be detected, the number of sensors can be reduced to half or less than half.

Next, the effect will be described.
In the impact detection sensor of the first embodiment, the effects listed below can be obtained.

  (1) In an impact detection sensor that has a pair of opposing electrode plates to form a pseudo capacitor and detects an impact by detecting changes in capacitance when electricity is passed through the pair of electrode plates, The deformed spherical deformed plate 2 (deformed plate), the fixed spherical plate 1 (fixed polar plate) disposed opposite to the deformed spherical plate 2, and the deformed spherical plate 2 Shock detection circuit 6 (capacitance change detecting means) that detects a change in capacitance between the two and two electrode plates 1 and 2 that changes due to deformation of the electrode plate. Can be avoided.

  (2) The spherical deformable electrode plate 2 (deformed electrode plate) and the spherical fixed electrode plate 1 (fixed electrode plate) constituting the pair of electrode plates have a similar shape fixed concentrically while maintaining an equal interval; The spherical deformable electrode plate 2 is set to have a shape in which the capacitance changes when even a part of the deformed electrode plate is deformed by an impact force. Therefore, if the input is to the plate surface area covered by the deformed electrode plate, an impact from any direction is detected. can do.

  (3) The impact detection circuit 6 (capacitance change detecting means) includes a power source 4 (voltage applying means) for applying a voltage to the bipolar plates, and the bipolar plates that change due to changes in capacitance between the bipolar plates. Therefore, it is possible to detect a change in capacitance with a very simple configuration.

  (4) The impact detection circuit 6 (capacitance change detection means) compares the voltage waveform of the power supply 4 (voltage application means) with the voltage waveform from the voltmeter 5 (voltage detection means) to determine the power supply voltage. Since the voltmeter waveform deviates from the phase delayed by 90 degrees with respect to the waveform, or when the peak voltage changes, the sensor main body has an impact judging circuit 7 for judging that the sensor body has undergone an impact. It is possible to accurately detect that the sensor body has received an impact by the simple impact judgment circuit 7 that simply judges the above.

  (5) Since it is applied as a collision detection means for the airbag system of a vehicle and is set at a position close to the outside of the vehicle, the impact detection sensor A1 is accompanied by the deformation of the vehicle body even at the time of a slight collision that deforms the vehicle body slightly. The spherical deformation electrode plate 2 is deformed in a concave manner, and a collision can be detected with high accuracy.

  (6) Since the set position to the vehicle is set at the left and right corner positions in front of the vehicle, it is possible to detect a vehicle collision over a wide range that is nearly double compared to the range that can be detected by the sensor of the prior art, When trying to detect the same collision range, the number of sensors can be reduced to half or less than half.

  (7) The fixed electrode plate and the deformed electrode plate are a spherical fixed electrode plate 1 set inside, and a spherical deformed electrode that is set outside the fixed ball plate 1 and covers the entire outer periphery of the fixed ball plate 1. Since the insulating support member 3 is set between the sphere fixed electrode plate 1 and the sphere deformed electrode plate 2 so as to keep the distance between the two electrode plates 1 and 2 equal to each other. The sensor A1 can be manufactured, and the impact detection sensor A1 alone can detect impacts from all three dimensions, and the impact sensitivity can be changed for each direction.

  The second embodiment is an example in which the fixed electrode plate and the deformed electrode plate are replaced with the spherical type of the first embodiment and an annular type (ring shape type or track shape type).

First, the configuration will be described.
FIG. 4 is an overall perspective view showing the impact detection sensor of the second embodiment.
In the impact detection sensor A2 according to the second embodiment, the fixed plate and the deformed plate are arranged inside an annular fixed plate 21 set inside and outside the annular fixed plate 21 as shown in FIG. An annular deformed electrode plate 22 that is set and covers the entire outer periphery of the annular fixed electrode plate 21. An insulating support member 23 is set between the annular fixed electrode plate 21 and the annular deformed electrode plate 22 to keep the distance between the two electrode plates 21 and 22 at an equal interval. In the second embodiment, an elliptical ring shape is shown, but an annular shape or an oval shape (track shape) may be used. Other configurations are the same as those in the first embodiment.

  Next, the operation will be described. While the impact detection sensor A1 of the first embodiment can detect a shock from any three-dimensional direction alone, the impact detection sensor A2 of the second embodiment Two-dimensional 360-degree impact in the X-axis direction and Y-axis direction can be detected, but the point that the impact in the Z-axis direction cannot be detected. Other functions are the same as those in the first embodiment.

Next, the effect will be described.
In the impact detection sensor A2 of the second embodiment, the following effects can be obtained in addition to the effects (1) to (6) of the first embodiment.

  (8) The fixed plate and the deformed plate are set inside the annular fixed plate 21 and outside the fixed plate 21 and cover the entire outer periphery of the fixed plate 21. An insulating support member 23 is set between the annular fixed electrode plate 21 and the annular deformed electrode plate 22 to keep the distance between the two electrode plates 21 and 22 equal. Compared to the impact detection sensor A1 of the first embodiment, the impact detection sensor A2 can be manufactured at a lower cost, and the impact detection sensor A2 can detect the impact from the two-dimensional circumferential direction alone. The impact sensitivity can be changed for each two-dimensional direction.

  Example 3 is an example in which the fixed electrode plate and the deformed electrode plate are replaced with the spherical type of Example 1 and a rectangular type (rectangular shape type or cubic shape type).

First, the configuration will be described.
FIG. 5 is an overall perspective view showing the impact detection sensor of the third embodiment.
In the impact detection sensor A3 according to the third embodiment, the fixed plate and the deformed plate are arranged in a rectangular fixed plate 31 set inside and outside the fixed plate 31 as shown in FIG. A rectangular deformation electrode plate 32 that is set and covers the entire outer periphery of the rectangular fixed electrode plate 31. Between the rectangular fixed electrode plate 31 and the rectangular deformed electrode plate 32, eight insulating support members 33 are set to keep the distance between the two electrode plates 31, 32 at an equal interval. In the third embodiment, a rectangular parallelepiped shape is shown, but of course, a cubic shape may be used.

  The rectangular fixed electrode plate 31 uses an outer case that accommodates in-vehicle components. Other configurations are the same as those in the first embodiment.

  Next, the operation will be described. In the impact detection sensor A1 of the first embodiment, it is possible to detect a shock from any three-dimensional direction alone, whereas the impact detection sensor A3 of the third embodiment Detects impacts from any three-dimensional direction so that the impact sensitivity in the X-axis direction, Y-axis direction, and Z-axis direction is the highest, and the impact sensitivity in the eight diagonal directions with the insulating support member 33 set is the lowest. It is possible to do this, but it differs in that the impact sensitivity varies with the direction.

  Since the present invention can completely cover the on-vehicle component, it is very effective for a component that particularly needs to be protected during a collision. In this case, many on-vehicle components are covered with a rectangular case in shape, and the impact detection sensor A3 of Example 3 can exhibit the most effective shape. Focusing on this point, in the impact detection sensor A3 of the third embodiment, the outer case that houses the in-vehicle component is used as the rectangular fixed plate 31 to achieve protection from collision damage of the in-vehicle component. . Other functions are the same as those in the first embodiment.

Next, the effect will be described.
In the impact detection sensor A3 of the third embodiment, in addition to the effects (1) to (6) of the first embodiment, the effects listed below can be obtained.

  (9) The fixed plate and the deformed plate are set to the inside of the rectangular fixed plate 31 set inside and the outside of the fixed plate 31 of the rectangular shape, and cover the entire outer periphery of the fixed plate 31 of rectangular shape. Because the insulating support member 33 is set between the rectangular fixed electrode plate 31 and the rectangular deformed electrode plate 32 to keep the distance between the two electrode plates 31 and 32 equal. The impact detection sensor A3 can be manufactured at a low cost, and the impact from any three-dimensional direction can be detected while changing the impact sensitivity for each direction with the impact detection sensor A3 alone.

  (10) Since the rectangular fixed plate 31 is an outer case that accommodates in-vehicle components, the in-vehicle components are protected from collision damage by covering the in-vehicle components with the rectangular deformed electrode plate 32 while sharing the components. Can do. In addition, it is possible to increase the degree of freedom of layout by enabling detection if the vehicle-mounted component is installed at any location of the vehicle if it is deformed.

  The fourth embodiment is an example in which the fixed electrode plate and the deformed electrode plate are replaced with the spherical type of the first embodiment and a hemispherical type is used.

First, the configuration will be described.
FIG. 6 is an overall perspective view showing the impact detection sensor of the fourth embodiment.
In the impact detection sensor A4 of the fourth embodiment, the fixed plate and the deformed plate are arranged on the inside of a hemispherical fixed plate 41 set inside and outside the hemispherical fixed plate 41, as shown in FIG. A hemispherical deformed electrode plate 42 that is set and covers the entire outer periphery of the hemispherical fixed electrode plate. The hemispherical fixed electrode plate 41 and the hemispherical deformed electrode plate 42 are set to a pedestal member 43 that keeps the electrode plates 41 and 42 at equal intervals.

In the impact detection sensor A4 of the fourth embodiment, the constituent elements of the hemispherical fixed electrode plate 41, the hemispherical deformed electrode plate 42, and the base member 43 are any of the following modes.
(a) The hemispherical fixed electrode plate 41, the hemispherical deformed electrode plate 42, and the pedestal member 43 are used as sensor constituent members, configured independently of the vehicle body panel, and installed on the vehicle body panel.
(b) The hemispherical fixed electrode plate 41 and the pedestal member 43 are vehicle body panels in which hemispherical convex portions or concave portions are formed, and only the hemispherical deformed electrode plate 42 is added. That is, the vehicle body panel formed of the metal body of the vehicle is regarded as one electrode plate of the sensor, and is effectively used as the hemispherical fixed electrode plate 41 and the base member 43.
(c) The base member 43 is a vehicle body panel of the vehicle, and a hemispherical fixed electrode plate 41 and a hemispherical deformed electrode plate 42 are added. That is, a vehicle body panel made of a metal body of the vehicle is used as the sensor base member 43 and is installed by being embedded in or protruding from the vehicle body.
Other configurations are the same as those in the first embodiment.

  Next, the operation will be described. The impact detection sensor A1 of the first embodiment can detect a shock from any three-dimensional direction alone, whereas the impact detection sensor A4 of the fourth embodiment The impact sensitivity from the positive Y-axis direction of the plane formed by the X-axis and the Z-axis is the highest, the input direction is shifted from the positive Y-axis direction, and the impact sensitivity gradually decreases as it approaches the X-axis or Z-axis. As described above, it is possible to detect an impact from the three-dimensional hemispherical direction, but the point that the impact sensitivity changes due to the input direction deviating from the positive direction of the Y-axis is different.

In the case of the impact detection sensor A4 of the fourth embodiment, as in the case of the first to fourth embodiments, an insulating support member is not required as a member for keeping a pair of electrode plates at equal intervals. Since the member that keeps the hemispherical deformed electrode plate 42 at equal intervals is the flat base member 43, it is possible to share parts with the vehicle body panel.
Focusing on this point, in the impact detection sensor A4 of the fourth embodiment, the hemispherical fixed electrode plate 41 and the pedestal member 43 can be configured by a vehicle body panel in which a hemispherical convex portion or concave portion is formed. In this case, it is possible to reduce two sensor parts. Moreover, the base member 43 can be comprised by the vehicle body panel of a vehicle, and it is possible to reduce one sensor component in this case. Other functions are the same as those in the first embodiment.

Next, the effect will be described.
In the impact detection sensor A4 of the fourth embodiment, in addition to the effects (1) to (6) of the first embodiment, the effects listed below can be obtained.

  (11) The fixed plate and the deformed plate are, as shown in FIG. 6, a hemispherical fixed plate 41 set inside and a hemispherical fixed plate set outside the hemispherical fixed plate 41. A hemispherical deformed electrode plate 42 covering the entire outer periphery of the plate, and the hemispherical fixed electrode plate 41 and the hemispherical deformed electrode plate 42 are set to a pedestal member 43 that keeps the two electrode plates 41, 42 at equal intervals. Therefore, the impact detection sensor A4 can be manufactured at a low cost, and the impact from the three-dimensional hemisphere direction can be detected by the single impact detection sensor A4, although the impact sensitivity changes depending on the input direction.

  (12) Since the hemispherical fixed electrode plate 41 and the pedestal member 43 are vehicle body panels formed with hemispherical convex portions or concave portions, separate sensors are unnecessary, and two sensor parts are reduced. The collision from any direction outside the vehicle can be detected by directing the hemispherical deformed electrode plate 42 to the outside of the vehicle.

  (13) Since the pedestal member 43 is a vehicle body panel, a separate sensor is not required, and the hemispherical deformation electrode plate 42 is directed to the outside of the vehicle while reducing one sensor component. It is possible to detect even a collision from the direction.

  As mentioned above, although the impact detection sensor of this invention has been demonstrated based on Example 1-Example 4, it is not restricted to these Examples about a concrete structure, Each claim of a claim Design changes and additions are allowed without departing from the gist of the invention.

  In Examples 1 to 4, a preferred example in which a fixed electrode plate and a deformed electrode plate having similar shapes fixed concentrically while maintaining an equal interval was shown, but even if the interval between the two electrode plates changes slightly, Moreover, it may not be fixed concentrically, and may not be a similar shape. In short, a pair of fixed electrode plate and deformed electrode plate are arranged to face each other, and when the deformed electrode plate is deformed by an impact force, the distance between the electrode plates is changed, and the capacitance is included in the present invention. .

Example 1 shows an example of a spherical electrode plate as a fixed electrode plate and a deformed electrode plate, Example 2 shows an example of an annular electrode plate as a fixed electrode plate and a deformed electrode plate, An example in which a rectangular plate is used as the fixed plate and the deformed plate is shown. In Example 4, an example in which a hemispherical plate is used as the fixed plate and the deformed plate is shown.
For example, in the case of the first embodiment, only a portion set to the vehicle body may be partially planarized.
For example, in the case of Example 2, it is good also as a ring shape combining a plane part and a curved surface part so that directionality may be given to impact sensitivity.
For example, in the case of Example 3, it may be divided into two by a plane passing through the center O, and two electrode plates may be fixed to the base member.
For example, in the case of Example 4, it is good also as a hemispherical shape by a polyhedron.

  In Examples 1-4, although the example of the impact detection sensor applied to the vehicle carrying an airbag system was shown, other than an airbag system, for example, the impact of an occupant protection device other than an in-vehicle airbag system As a detection sensor, it can also be applied to an impact detection sensor of a structure that is deformed or damaged by an earthquake.

1 is an overall perspective view showing an impact detection sensor of Example 1. FIG. It is a figure which shows an example of the impact detection circuit of the impact detection sensor of Example 1, and an impact determination circuit. It is a figure which shows an example of the vehicle carrying the airbag system to which the impact detection sensor of Example 1 was applied. It is a whole perspective view which shows the impact detection sensor of Example 2. FIG. It is a whole perspective view which shows the impact detection sensor of Example 3. It is a whole perspective view which shows the impact detection sensor of Example 4.

Explanation of symbols

A1 Impact detection sensor 1 Sphere fixed plate (fixed plate)
2 Spherical deformation electrode plate (deformation electrode plate)
3 Insulation support member 4 Power supply (voltage application means)
5 Voltmeter (voltage detection means)
6 Impact detection circuit (Capacitance change detection means)
7 Impact judgment circuit
A2 Impact detection sensor 21 Annular fixed plate (fixed plate)
22 Toroidal deformed plate (deformed plate)
23 Insulation support member
A3 Impact detection sensor 31 Rectangular fixed plate (fixed plate)
32 Rectangular deformation electrode plate (deformation electrode plate)
33 Insulation support member
A4 Impact detection sensor 41 Hemispherical fixed plate (fixed plate)
42 Hemispherical deformed plate (deformed plate)
43 Base member

Claims (14)

In an impact detection sensor that detects a shock by detecting a change in capacitance when electricity is passed through a pair of electrode plates, a pseudo capacitor having a pair of electrode plates facing each other,
A deformed electrode plate formed to be deformable by an impact force;
A fixed electrode plate disposed opposite to the deformed electrode plate;
A capacitance change detecting means for detecting a change in capacitance between the two electrode plates, which is changed by deformation of the deformed electrode plate;
An impact detection sensor comprising: The impact detection sensor according to claim 1,
The deformed electrode plate and the fixed electrode plate constituting the pair of electrode plates have a similar shape fixed concentrically while maintaining an equal interval, and the deformed electrode plate is electrostatically deformed even when partly deformed by an impact force. An impact detection sensor characterized by having a shape that changes its capacity. In the impact detection sensor according to claim 1 or 2,
The capacitance change detecting means includes a voltage applying means for applying a voltage to the bipolar plates, and a voltage detecting means for detecting a voltage for detecting a voltage between the bipolar plates that changes due to a change in capacitance between the bipolar plates. And an impact detection sensor. In the impact detection sensor according to claim 3,
The capacitance change detecting means compares the voltage waveform of the voltage applying means with the voltage waveform of the voltage detecting means, and the detected voltage waveform is shifted from the phase delayed by 90 degrees with respect to the applied voltage waveform, or the peak voltage An impact detection sensor comprising: an impact determination circuit that determines that the sensor body has received an impact when a change occurs. In the impact detection sensor according to any one of claims 1 to 4,
An impact detection sensor which is applied as a collision detection means of a vehicle airbag system and is set at a position near the outside of the vehicle. The impact detection sensor according to claim 5,
The impact detection sensor, wherein the set position on the vehicle is at least one of left and right corner positions in front of the vehicle. The impact detection sensor according to any one of claims 1 to 6,
The fixed electrode plate and the deformed electrode plate are a sphere fixed electrode plate set inside, and a sphere deformed electrode plate set outside the sphere fixed electrode plate and covering the entire outer periphery of the sphere fixed electrode plate,
An impact detection sensor characterized in that an insulating support member is set between the spherical fixed electrode plate and the spherical deformed electrode plate to keep the distance between the two electrode plates at an equal interval. The impact detection sensor according to any one of claims 1 to 6,
The fixed plate and the deformed plate are an annular fixed plate that is set inside, and an annular deformed plate that is set outside the annular fixed plate and covers the entire outer periphery of the annular fixed plate. , And
An impact detection sensor characterized in that an insulating support member is set between the annular fixed electrode plate and the annular deformed electrode plate to keep the distance between the two electrode plates at an equal interval. The impact detection sensor according to any one of claims 1 to 6,
The fixed electrode plate and the deformed electrode plate are a rectangular fixed electrode plate set inside, and a rectangular deformed electrode plate set outside the rectangular fixed electrode plate and covering the entire outer periphery of the rectangular fixed electrode plate, , And
An impact detection sensor, wherein an insulating support member is set between the rectangular fixed electrode plate and the rectangular deformed electrode plate to keep the distance between the two electrode plates at an equal interval. In the impact detection sensor according to claim 9,
The impact detection sensor according to claim 1, wherein the rectangular fixed electrode plate is an outer case for housing a vehicle-mounted component. The impact detection sensor according to any one of claims 1 to 6,
The fixed plate and the deformed plate are a semispherical fixed plate set inside, and a hemispherical deformed plate set outside the hemispheric fixed plate and covering the entire outer periphery of the hemispheric fixed plate , And
The impact detection sensor according to claim 1, wherein the hemispherical fixed electrode plate and the hemispherical deformed electrode plate are set as a pedestal member that keeps both electrode plates at equal intervals. The impact detection sensor according to claim 11,
The impact detection sensor according to claim 1, wherein the hemispherical fixed electrode plate and the pedestal member are vehicle body panels formed with hemispherical convex portions or concave portions. The impact detection sensor according to claim 11,
The impact detection sensor, wherein the pedestal member is a vehicle body panel. In an impact detection sensor that detects a shock by detecting a change in capacitance when electricity is passed through a pair of electrode plates, a pseudo capacitor having a pair of electrode plates facing each other,
The pair of electrode plates is constituted by a fixed electrode plate and a deformed electrode plate arranged to face each other,
When electricity is applied to a pair of electrode plates composed of the fixed electrode plate and the deformed electrode plate, when an impact force is applied to the deformed electrode plate and its shape is deformed, the capacitance changes due to the deformation. An impact detection sensor that detects an input of an impact force by detecting the impact.

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