JP4890589B2 - Vehicle collision detection device - Google Patents

Description

  The present invention relates to a vehicle collision detection device that detects a vehicle collision.

  As a technique related to a vehicle collision detection sensor for detecting a vehicle collision, there is a technique in which a large number of sensor elements each including a hexagonal piezoelectric film are continuously arranged so as to form a plane (for example, Patent Documents). 1). In such a vehicle collision detection sensor, each sensor element is provided with an electrode pair that is arranged so as to sandwich the piezoelectric film from both sides and detects the voltage, and the collision is detected from the voltage value of each sensor element. Will be detected.

JP-T 8-509934

  However, in the above-described vehicle collision detection sensor, it is necessary to continuously arrange the hexagonal piezoelectric film so as to form a plane, and to each piezoelectric film continuously disposed in the plane. Since an electrode pair for voltage detection is necessary, there is a problem that the manufacturing cost is increased.

  Therefore, an object of the present invention is to provide a vehicle collision detection device that can reduce manufacturing costs.

In order to achieve the above object, the invention according to claim 1 is directed to a single piezoelectric film (for example, the piezoelectric film 15 in the embodiment) that has a rectangular shape that is long in the vehicle width direction and that spreads continuously in a plane, and a vehicle. Three or more electrode pairs (for example, electrode pair 18 in the embodiment) which are arranged on the piezoelectric film so as to be provided on substantially the same straight line along the width direction and detect a voltage, and between these three or more electrode pairs A vehicle collision detection sensor (for example, the vehicle collision detection sensor 10 in the embodiment) provided on the inner surface of the bumper face with a space provided, and a vehicle collision based on a detection value of the vehicle collision detection sensor. And a control means for detecting (for example, the SRS control unit 27 in the embodiment). An estimate of the value, while estimating seeking gently connecting line between the detection value, based on the generation region of the maximum value and the detection value before Symbol line, to determine the form of the collision, of the collision actuating the safety device in accordance with the embodiment is characterized in Rukoto.

The invention according to claim 2 is the invention according to claim 1, wherein the control means generates a maximum value of the line at one end portion in the vehicle width direction and indicates a value lower than a predetermined value and When the generation area extends to the center in the vehicle width direction, it is determined that the collision is not a collision with a pedestrian, and the seat belt is wound by the seat belt retractor, which is the safety device, at a predetermined timing for occupant protection. And the airbag device as the safety device is activated at a predetermined timing .

According to a third aspect of the present invention, in the invention according to the first or second aspect, the control means, when the maximum value of the line is generated at the center in the vehicle width direction and indicates a value higher than a predetermined value, In order to protect the occupant, the seat belt is retracted by the seat belt retractor as the safety device at a predetermined timing, and the air as the safety device is detected at the predetermined timing. The bag device is actuated .

The invention according to a fourth aspect is the invention according to any one of the first to third aspects, wherein the control means generates a maximum value of the line at a center in the vehicle width direction and a value lower than a predetermined value. When the detection value generation area does not extend to one end in the vehicle width direction, it is determined that the collision with the pedestrian and the hood hood that is the safety device is lifted at a predetermined timing to protect the pedestrian It is characterized by operating the device and floating the hood .
The invention according to a fifth aspect is the invention according to any one of the first to fourth aspects, wherein the electrode pair is disposed so as to sandwich the piezoelectric film from both sides in the thickness direction in a state of being aligned with each other. And a pair of electrodes for detecting the electric charge generated in the piezoelectric film as a voltage.

  According to the present invention, since a plurality of pairs of electrodes are provided at intervals with respect to a single piezoelectric film that spreads continuously in a plane, the pressure applied to the position where the electrode pairs are provided is of course. The pressure applied to the position where the electrode pair of the piezoelectric film is not provided is also transmitted from the pressure portion in the in-plane direction of the piezoelectric film, and as a result, is located away from the pressure portion. The voltage can be detected by the electrode pair. And, by immediately analyzing the voltage of each electrode pair comprehensively, it is possible to detect the form of the collision and the magnitude of the collision force, and to determine what kind of collision, based on this, Appropriate selection of the collision safety device to be activated can be made. Therefore, it is not necessary to arrange a large number of piezoelectric films, and the number of electrode pairs can be reduced, so that the manufacturing cost can be reduced.

1 is a plan view schematically showing a front portion of a vehicle in which a vehicle collision detection apparatus according to an embodiment of the present invention is used. It is a perspective view which shows the vehicle collision detection sensor of the vehicle collision detection apparatus of one Embodiment of this invention. It is a characteristic line figure which shows the output characteristic of each collision form in the vehicle collision detection sensor of the vehicle collision detection apparatus of one Embodiment of this invention.

  A vehicle collision detection apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the vehicle collision detection sensor 10 of the present embodiment is provided near the outer surface of the vehicle 11 and detects an external input to the vehicle 11, that is, a collision. Specifically, It is provided on the inner surface of the front bumper face 12 and mainly detects a frontal collision.

  As shown in FIG. 2, the vehicle collision detection sensor 10 includes a piezoelectric film 15 that spreads continuously in a planar shape. The piezoelectric film 15 is made of a polymer material, and generates electric charges when strain is applied, and conversely generates distortion when electric charges are applied.

  Further, the vehicle collision detection sensor 10 includes a pair of electrodes 17 that are arranged so as to sandwich the piezoelectric film 15 from both sides in the thickness direction in a state of being aligned with each other and detect electric charges generated in the piezoelectric film 15 as a voltage. An electrode pair 18 is provided. Here, with respect to one piece of the piezoelectric film 15, a plurality of pairs of the electrode pairs 18 described above are provided at a predetermined interval.

  The piezoelectric film 15 has a rectangular shape that is long in the horizontal direction, and three or more electrode pairs 18 are provided in the length direction of the piezoelectric film 15, and six pairs in the illustrated example. That is, three or more pairs of electrode pairs 18 are provided on substantially the same straight line. The electrode pair 18 is provided at both end portions and an intermediate portion in the length direction of the piezoelectric film 15 and is disposed with a predetermined interval.

  The electrodes 17 of each electrode pair 18 are made of a rectangular thin plate, a metal paste, or a vapor deposition metal, and are pasted, applied, or vapor deposited on the piezoelectric film 15 so as to extend over the entire width of the piezoelectric film 15. A wire 20 shown in FIG. 1 is connected to each electrode 17.

  Although the vehicle collision detection sensor 10 of the present embodiment described above is not illustrated, is it attached directly to the inner surface of the front bumper face 12 in a state of being entirely covered with, for example, a bag-like covering member made of an insulating material? Alternatively, it is attached to the inner surface of the front bumper face 12 via a support plate made of a synthetic resin material or the like. At this time, the vehicle collision detection sensor 10 causes the length direction of the piezoelectric film 15 to be along the vehicle width direction so that the plurality of electrode pairs 18 are arranged in the vehicle width direction, and the width direction of the piezoelectric film 15 is set to the vertical direction. It is assumed that it is in line.

  Each electrode pair 18 of the vehicular collision detection sensor 10 is connected to a signal conditioner 25 in which each wiring 20 is disposed in the engine room. The signal conditioner 25 is connected to each electrode pair 18 from each electrode pair 18. The electrical signal is subjected to processing such as increasing the signal strength to reduce the noise and transmitting the signal to the SRS control unit (control means) 27 in the passenger compartment. The vehicle collision detection sensor 10, the signal conditioner 25, and the SRS control unit 27 constitute the vehicle collision detection device 1.

  The SRS control unit 27 determines the collision type, the magnitude of the collision force, and the like based on the voltage value detected by each electrode pair 18. Here, the vehicle 11 includes, as a collision safety device, an airbag device 29 that deploys an airbag, a seat belt retractor 30 that forcibly winds up the seat belt, and a bonnet hood that forcibly floats the hood. An upper device 31 is provided. Whether the SRS control unit 27 is a collision with a pedestrian or other collision based on detection data of the vehicle collision detection sensor 10 and vehicle speed data detected by a vehicle speed sensor (not shown). Etc., and the operation of the airbag device 29, the seat belt retractor 30 and the hood lifting device 31 is controlled.

  The SRS control unit 27 determines from the signal of each electrode pair 18 whether a full lap collision, a POLE collision, an offset collision at the initial stage of the collision, or an offset amount to the left or right if a POLE collision or an offset collision. In addition, the magnitude of the collision is estimated, and the type and magnitude of the collision are determined using the G sensor or satellite G sensor signal in the SRS control unit 27. The SRS control unit 27 controls each operation of the airbag device 29, the seat belt retractor 30, and the hood lifting device 31 according to the determination result of the collision type and the magnitude of the collision force.

  For example, as shown in FIG. 3, the positions of the electrode pairs 18 arranged in the vehicle width direction (positions (a) to (f) in FIG. 3 correspond to positions (a) to (f) in FIG. 2) When the detected value of the electrode pair 18 at each position is taken on the axis, the detected value of each electrode pair 18 is almost equal and high when the front collides with a flat rigid wall having a fixed area and a large area. Will be shown. At this time, the estimated value of the detection value of each part between each electrode pair 18 can be obtained by drawing the line which connects each detection value gently. In this case, it can be estimated that the estimated value of the detected value of each part between each electrode pair 18 also shows the same value as each detected value, as shown by the solid line A in FIG. When such data is obtained, the SRS control unit 27 determines that the collision is a collision other than a collision with a pedestrian and is a destruction mode collision, and takes up the seat belt at a predetermined timing to protect the passenger. The seat belt is wound up by the device 30 and the airbag device 29 is operated at a predetermined timing. That is, the vehicle collision detection sensor 10 functions as a collision detection sensor for airbag operation control.

  In addition, when a collision is caused by offsetting in the vehicle width direction to a soft object whose position is fixed, the detection value at each electrode pair 18 is high at the collision-side electrode pair 18 as shown by a one-dot chain line B in FIG. The lower it becomes. Also at this time, an estimated value of the detected value of each part between the electrode pairs 18 can be obtained by drawing a curve that smoothly connects the detected values, and the maximum detected value indicating the collision force and its occurrence The position can also be estimated. In this case, it can be seen that the maximum value of the detection value occurs at one end in the vehicle width direction and shows a relatively low value, and the generation position extends over a relatively wide range. Even when such data is obtained, the SRS control unit 27 determines that the collision is a collision other than a collision with a pedestrian and a destruction mode collision, and takes up the seat belt at a predetermined timing to protect the occupant. The seat belt is wound up by the device 30 and the airbag device 29 is operated at a predetermined timing.

  Further, when a frontal collision occurs in the center in the vehicle width direction on a rigid body having a small area with a fixed position such as a utility pole, the detected value at each electrode pair 18 is the value at the collision-side electrode pair 18 as shown by the broken line C in FIG. The lower the height is on both sides in the vehicle width direction. Also at this time, by drawing a curve that smoothly connects the detected values, it is possible to obtain an estimated value of the detected value of each part between the electrode pairs 18, and the maximum value indicating the collision force and the generation position thereof are also obtained. Can be estimated. In this case, it can be seen that the maximum detected value occurs at the center in the vehicle width direction where the electrode pair 18 is not disposed and shows a high value. Even when such data is obtained, the SRS control unit 27 determines that the collision is a collision other than a collision with a pedestrian and a destruction mode collision, and takes up the seat belt at a predetermined timing to protect the occupant. The seat belt is wound up by the device 30 and the airbag device 29 is operated at a predetermined timing.

  In addition, since it is possible to determine whether it is not a destructive mode collision as described above, for example, a non-destructive mode collision that collides with a curb or the like from the magnitude of the detected value indicating the collision force. In the case of a non-destructive mode collision, the SRS control unit 27 performs control so as not to activate the airbag device 29, for example.

  When a pedestrian makes a frontal collision at the center in the vehicle width direction, the detected value at each electrode pair 18 is higher at the collision-side electrode pair 18 as shown by a two-dot chain line D in FIG. Lower. Also at this time, an estimated value of the detected value of each part between the electrode pairs 18 can be obtained by drawing a curve that smoothly connects the detected values, and the maximum detected value indicating the collision force and its occurrence The position can also be estimated. Also in this case, the maximum value is generated at the center in the vehicle width direction where the electrode pair 18 is not disposed and shows a relatively low value, and the generation region of the detection value is relatively narrow. When such data is obtained, the SRS control unit 27 determines that it is a collision with a pedestrian, and in order to protect the pedestrian, the hood hood lifting device 31 is operated at a predetermined timing to remove the hood hood. Make it float. That is, the vehicle collision detection sensor 10 of the present embodiment also functions as a collision detection sensor for detecting pedestrian collisions.

  According to the vehicle collision detection sensor 10 of the present embodiment described above, a plurality of pairs of electrodes 18 are provided at intervals with respect to one piezoelectric film 15 continuously spreading in a planar shape. Of course, not only the pressure applied to the position where the electrode pair 18 is provided, but also the pressure applied to the position where the electrode pair 18 of the piezoelectric film 15 is not provided, the in-plane direction of the piezoelectric film 15 from this pressing portion. Since the stress is transmitted to the electrode pair, the voltage value can be detected by the electrode pair 18 located away from the pressurizing portion. Then, the form of collision and the magnitude of the collision force can be detected by analyzing the voltage value of each electrode pair 18 comprehensively and immediately, and it is possible to determine the type of collision. Thus, an appropriate selection of the collision safety device to be activated can be made. Therefore, it is not necessary to arrange a large number of piezoelectric films 15 and the number of electrode pairs 18 can be reduced, so that the manufacturing cost can be reduced.

  Moreover, since three or more electrode pairs 18 are provided on substantially the same straight line, the detection accuracy can be improved. Therefore, it is possible to more accurately detect the type of collision and the magnitude of the collision force, more accurately determine the type of collision, and more appropriately select the collision safety device to be activated. be able to.

  In addition, since the vehicle collision detection sensor 10 of the present embodiment serves as both a collision detection sensor for detecting pedestrian collision and a collision detection sensor for controlling airbag operation, the cost can be further reduced. it can. Moreover, since it is provided on the front bumper face 12, it is possible to determine the type of collision by detecting the type of collision and the magnitude of the collision force at the initial stage of collision without waiting for deformation of the body frame. This allows for the proper selection and early activation of the collision safety device to be activated.

  In the above description, the case where the vehicle collision detection sensor 10 is provided on the inner surface of the front bumper face 12 to detect mainly frontal collisions has been described as an example. Of course, it is possible to detect the side collision mainly by providing it on the inner surface of the door outer plate.

  In the above description, the case where the electrode pairs 18 are arranged in the length direction of the piezoelectric film 15 has been described as an example. However, the electrode pairs 18 are arranged in a matrix in the length direction and width direction (vertical direction) of the piezoelectric film 15. The voltage value may be detected by each electrode pair 18.

  Furthermore, in the above, the signal conditioner 25 serves to increase the signal strength and send a signal with less noise to the SRS control unit 27. However, the signal conditioner 25 performs a certain amount of signal processing, You may have the function etc. which judge whether it is a pedestrian collision or another collision. Here, the signal from the signal conditioner 25 to the SRS control unit 27 may be an analog signal or a digital signal.

  In addition, as shown in FIG. 1, the output of each electrode pair 18 can be processed by a single signal conditioner 25, but the signal conditioner 25 may be provided independently for each electrode pair 18. good.

11 Vehicle 12 Front Bumper Face 15 Piezoelectric Film 18 Electrode Pair

Claims (5)

And one of the piezoelectric film extending in the vehicle width direction forms a long rectangular shape in a plane to continuously disposed to the piezoelectric film to be provided on the approximate straight line along the vehicle width direction to detect a voltage three A vehicle collision detection sensor provided on the inner surface of the bumper face with a pair of or more electrode pairs and a space provided between the three or more electrode pairs;
Control means for detecting a vehicle collision based on a detection value of the vehicle collision detection sensor,
Is the control means, wherein an estimate of the maximum value of the detected values indicating the estimated value and the collision force of the detected values in space, with estimates seeking gently connecting line between the detection value, the pre-Symbol line based maximum value in the generation region of the detected value, to determine the form of the collision, the vehicle collision detection apparatus according to claim Rukoto actuates a safety device in accordance with the form of the collision. When the maximum value of the line is generated at one end portion in the vehicle width direction and is lower than a predetermined value and the detection value generation area extends to the center in the vehicle width direction, the control means It is determined that the collision is other than a collision, and for protecting the occupant, the seat belt is wound by the seat belt retractor, which is the safety device, at a predetermined timing, and the airbag device, which is the safety device, at the predetermined timing The vehicle collision detection device according to claim 1, wherein the vehicle collision detection device is operated . When the maximum value of the line occurs at the center in the vehicle width direction and shows a value higher than a predetermined value, the control means determines that the collision is other than a collision with a pedestrian, and for the purpose of passenger protection The seat belt is wound by the seat belt retractor, which is the safety device, at the timing, and the airbag device, which is the safety device, is activated at a predetermined timing. Vehicle collision detection device. When the maximum value of the line is generated at the center in the vehicle width direction and is lower than a predetermined value, and the detection value generation area does not extend to one end in the vehicle width direction, the control means The bonnet hood is floated by operating the hood hood lifting device, which is the safety device, at a predetermined timing in order to protect a pedestrian. The vehicle collision detection device according to the item. The electrode pair includes a pair of electrodes that are arranged so as to sandwich the piezoelectric film from both sides in the thickness direction in a state of being aligned with each other, and detect electric charges generated in the piezoelectric film as a voltage. Item 5. The vehicle collision detection device according to any one of Items 1 to 4 .

Images