JP6515881B2 - Vehicle collision detector - Google Patents

Description

  The present invention relates to a vehicle collision detection device for detecting a collision of a pedestrian or the like with a vehicle.

  There is a prior art related to a collision detection device in which a vehicle sensor module formed by holding a plurality of collision sensors including a piezoelectric film and a signal processing device in a housing is attached to the rear of a bumper cover (for example, patent documents 1). In the collision detection device, when a collision of a pedestrian or the like occurs in the bumper cover, an output signal is formed according to the strain generated in the collision sensor, so that the signal processing device generates a signal based on the output signal. A collision is detected.

JP 2007-223535 A

By the way, in order to accurately detect a collision that has occurred in the bumper cover in the collision detection device described above, the collision sensor needs to be securely fixed to the bumper cover. Usually, when attaching a collision sensor to a bumper cover, an adhesive agent or a double-sided adhesive tape often joins a bumper cover and a collision sensor. For this reason, it is conceivable that the bonding strength between the both is reduced due to adhesion of mud water or the like to the bonding portion, a change in the ambient temperature, a change with time of the body parts, There is a problem that it is difficult to accurately detect the occurrence of a collision in the vehicle when a part of the collision sensor peels off from the bumper cover due to the decrease in the bonding force. Therefore, in this case, in order to stop the operation of the collision detection device, it was necessary to accurately detect the separation of the collision sensor from the bumper cover.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a highly reliable vehicle collision detection device capable of accurately determining the attachment state of a collision sensor to a bumper cover. .

In order to solve the problems described above, the invention of a collision detection device for a vehicle according to claim 1 includes a piezoelectric film and a pair of flat electrodes sandwiching both sides of the piezoelectric film, and between the electrodes according to the generated deformation In the bumper cover based on the collision sensor generating a predetermined output signal, the base film interposed between the collision sensor and the inner surface of the bumper cover of the vehicle, and the output signal formed by the collision sensor, A collision detection device for a vehicle comprising: a collision determination unit that detects that a collision requiring the operation of a protection device for protecting a collision object has occurred; and it is joined to a bumper cover of a base film A deformation input unit for inputting a load to a non-existing portion to deform the base film, and a deformation signal which is an output signal generated when the base film is deformed by the deformation input unit Based on the predefined defining signal as a modified signal which respect the bumper cover occurs in a state where the collision sensor through the substrate film is attached properly, determine the presence or absence of improper mounting of the collision sensor with respect to the bumper cover And an attached state determination unit.

According to this configuration, in the vehicle collision detection device, the collision sensor is properly attached to the deformation signal generated when the base film is deformed by the deformation input unit and the bumper cover via the base film. And a mounting state determination unit that determines the presence or absence of a mounting failure of the collision sensor on the bumper cover based on the deformation signal in the case where the vehicle is mounted. Thereby, the attachment defect of the collision sensor with respect to the bumper cover resulting from the base film having peeled off from the bumper cover or the collision sensor having peeled off from the base film can be detected. Therefore, when a mounting failure of the collision sensor occurs, the driver of the vehicle can be warned and the operation of the collision detection device for the vehicle can be stopped, so that the collision detection device for the vehicle can be made highly reliable. be able to.
The collision detection device for a vehicle according to the present invention is not intended to detect only pedestrian collisions, but is directed to all collision detections that require the pedestrian protection device to be activated.

Top view of a vehicle equipped with a pedestrian protection system according to Embodiment 1 of the present invention II-II sectional view of FIG. 1 A view of the collision detection sensor shown in FIG. 2 as viewed from the rear of the vehicle IV-IV sectional view of FIG. 3 Block diagram showing the configuration of the pedestrian protection system Diagram showing the operation at the time of mounting defect determination by the collision detection sensor shown in FIG. 3 VII-VII sectional drawing of FIG. 6 Diagram showing a control flowchart of the pedestrian protection system The collision detection sensor according to the first modification of the first embodiment viewed from the rear of the vehicle A view of a collision detection sensor according to a second modification of the first embodiment as viewed from the rear of the vehicle The collision detection sensor according to the second embodiment viewed from the rear of the vehicle The collision detection sensor according to the third embodiment viewed from the rear of the vehicle XIII-XIII sectional view of FIG. 12

  The first to third embodiments of the present invention will be described below. Unless otherwise specified, the descriptions indicating directions in the description and in FIGS. 1 to 12 correspond to the directions for the driver seated on the vehicle VE. For example, in the drawing, the display of "front" indicates that the direction of the arrow corresponds to the front of the vehicle VE. Further, the following description is focused on the collision of the pedestrian with the vehicle VE. However, the pedestrian protection system 1 (corresponding to the collision detection device for a vehicle) according to the present invention is not only intended to detect pedestrian collisions, but it is also possible to use a pedestrian protection device 5 (described later) such as a bicycle or a stroller. It covers all collision detection that needs to be activated.

<Configuration of Embodiment 1>
A pedestrian protection system 1 according to a first embodiment of the present invention will be described based on FIGS. 1 to 8.
(Overall configuration of pedestrian protection system)
As shown in FIG. 1, a front bumper 21 is attached to the front end of the vehicle VE. The front bumper 21 extends in the left-right direction, and includes a bumper cover 22 and a bumper absorber 23. The bumper cover 22 is formed of a synthetic resin material, and forms a design surface at the front of the vehicle VE. The bumper absorber 23 is provided at the rear of the bumper cover 22 as an impact absorbing material when a collision occurs in the front bumper 21. The bumper absorber 23 is formed of, for example, a foamed resin such as foamed polypropylene.

  The bumper absorber 23 is attached to the front surface 24 a of the bumper reinforcement 24 at the rear end face 23 a. The bumper reinforcement 24 is a strength member hollow inside by a metal material such as an aluminum alloy and extends in the left-right direction. The bumper reinforcements 24 are fixed to the front end portions of the pair of left and right side members 25R, 25L extending in the front-rear direction. A body unit 2 is formed by the front bumper 21, the bumper reinforcement 24 and the side members 25R, 25L described above.

  As shown in FIGS. 1 and 2, a collision detection sensor 3 is attached to a back surface 22 a (corresponding to an inner side surface of the bumper cover) which is a rear surface of the bumper cover 22. The collision detection sensor 3 extends in the vehicle width direction (lateral direction) so as to connect both ends of the bumper cover 22. The collision detection sensor 3 is preferably mounted at a height at which a pedestrian or the like collides on the vehicle VE.

  As shown in FIG. 3, the collision detection sensor 3 includes a plurality of sensor elements 31 (each corresponding to a collision sensor and a sensor cell) and a base film 32 holding the sensor elements 31. In addition, in FIG. 3, the full length in the left-right direction of the collision detection sensor 3 is shortened from actual and schematically shown, and the same applies to FIG. The configuration including the plurality of sensor elements 31 corresponds to a collision sensor. Each of the sensor elements 31 is a flat plate-shaped first division which is joined to the piezoelectric polymer film 31a (corresponding to a piezoelectric film and a divided piezoelectric film) formed in a thin film shape and the piezoelectric polymer film 31a. It has an electrode 31 b and a second divided electrode 31 c (both correspond to a pair of electrodes and a pair of divided electrodes) (shown in FIG. 4). In FIGS. 3 and 6, only one of the plurality of sensor elements 31 and the first divided electrodes 31b is denoted by the reference numeral.

  The piezoelectric polymer film 31a is formed of a piezoelectric polymer material such as polyvinylidene fluoride (PVDF), a polypeptide, polylactic acid, polymethyl glutamate, and polybenzyl glutamate. The first divided electrode 31 b and the second divided electrode 31 c are formed of a conductive metal film such as copper, aluminum, silver paste or the like, and sandwich the piezoelectric polymer film 31 a from both sides. Hereinafter, the first divided electrodes 31 b and the second divided electrodes 31 c are collectively referred to as divided electrodes 31 b and 31 c.

  The base film 32 is formed of a synthetic resin material in a film shape, and is interposed between each sensor element 31 and the back surface 22 a of the bumper cover 22. The surface 32a on one side of the base film 32 is bonded to the surface of the second divided electrode 31c not attached to the piezoelectric polymer film 31a. As a result, the plurality of sensor elements 31 are arranged on the base film 32 so as to form columns and rows, and adjacent ones are held apart from each other (see FIG. 3). The sensor element 31 is bonded to the base film 32 by an adhesive or a double-sided adhesive tape.

  The surface 32 b of the base film 32 not bonded to the second divided electrode 31 c (hereinafter, referred to as the other surface 32 b) is attached to the back surface 22 a of the bumper cover 22. The base film 32 has a substantially rectangular shape, and is bonded to the bumper cover 22 at four corners CP which is a portion to which the sensor element 31 is not bonded. The base film 32 is bonded to the bumper cover 22 by an adhesive or double-sided adhesive tape.

When the bumper cover 22 is deformed due to the collision, the base film 32 is deformed together with the bumper cover 22. Due to the deformation of the base film 32, the sensor element 31 is also deformed in the pulling direction or in the compression direction, and a predetermined output voltage Vpz (corresponding to an output signal corresponding to the amount of deformation generated between divided electrodes 31b and 31c). The piezo film voltage Vpz is generated.
Conversely, when a predetermined drive voltage Vip is applied between the divided electrodes 31b and 31c, the sensor element 31 is deformed in the pulling direction or the compression direction. The piezoelectric polymer film itself is known, and is disclosed, for example, in Japanese Patent Application Laid-Open Nos. 2004-96980, 2007-212436, and 2013-29368, which are public patent publications.

Returning to FIG. 1, the speed sensor 4 provided in the vehicle VE is attached to the wheel or transmission of the vehicle VE, and detects the traveling speed of the vehicle VE.
The cowl airbag device 51 is included in the pedestrian protection device 5 (corresponding to the protection device). When a pedestrian collides with the front bumper 21, the cowl airbag device 51 deploys the bag from above the engine hood HE shown in FIG. 1 to the lower part of the front window WF to protect collision objects such as pedestrians who collided.

The pop-up hood 52 is also included in the pedestrian protection device 5. The pop-up hood 52 raises the rear end of the engine hood HE when a pedestrian or the like collides with the front bumper 21. As a result, the engine hood HE serves as a buffer member to prevent a pedestrian from colliding with a rigid member such as an engine, thereby protecting a colliding object such as a pedestrian who has collided.
An instrument panel 6 (hereinafter referred to as an instrument panel 6) is provided in front of the driver's seat of the vehicle VE. The instrument panel 6 is formed to be able to display a warning to the driver when a mounting defect of the sensor element 31 with respect to the bumper cover 22 via the base film 32 is detected. Hereinafter, attachment of the sensor element 31 to the bumper cover 22 through the base film 32 may be referred to as attachment of the sensor element 31 to the bumper cover 22 by omitting “through the base film 32”.

(Configuration of pedestrian protection ECU)
In the vehicle VE, a pedestrian protection ECU 7 is mounted on a floor tunnel on the front side of the driver's seat (not shown). The pedestrian protection ECU 7 is a control device formed by an input / output device (not shown), a CPU, a RAM, and the like. As shown in FIG. 1, the collision detection sensor 3, the speed sensor 4, the cowl airbag device 51, the pop-up hood 52 and the instrument panel 6 described above are connected to the pedestrian protection ECU 7 by communication lines.

As shown in FIG. 5, the pedestrian protection ECU 7 includes a vehicle speed determination unit 71, a collision determination unit 72, a deformation application unit 73, an attachment state determination unit 74, an AND circuit 75, and a protection device driver 76.
The vehicle speed determination unit 71 is connected to the speed sensor 4. The vehicle speed determination unit 71 determines whether the vehicle speed detection value Sdet detected by the speed sensor 4 is equal to or greater than a predetermined first vehicle speed threshold Sth1 and equal to or less than a predetermined second vehicle speed threshold Sth2 greater than the first vehicle speed threshold Sth1. judge. The vehicle speed determination unit 71 outputs a high (H) signal when the vehicle speed detection value Sdet is equal to or greater than the first vehicle speed threshold Sth1 and equal to or less than the second vehicle speed threshold Sth2.

  The collision determination unit 72 is connected to the collision detection sensor 3. The collision determination unit 72 compares the piezo film voltage Vpz input from the sensor element 31 with a predetermined voltage threshold Vth. When the piezo film voltage Vpz is equal to or higher than the voltage threshold Vth, the collision determination unit 72 detects that a collision requiring the operation of the pedestrian protection device 5 has occurred in the bumper cover 22 and outputs an H signal. Further, a predetermined operation voltage is formed based on the piezoelectric film voltage Vpz for the reason of operation processing, and when the operation voltage is equal to or higher than the voltage threshold Vth, the operation of the pedestrian protection device 5 is performed in the collision determination unit 72. It may be determined that a collision has occurred that requires.

The deformation applying unit 73 (corresponding to a deformation input unit) inputs a load to a portion of the base film 32 which is not joined to the bumper cover 22 and deforms the base film 32 in a direction in which the base film 32 is pulled.
The attachment state determination unit 74 detects a deformation voltage Vdg (corresponding to a deformation signal) generated between the divided electrodes 31 b and 31 c when the base film 32 is deformed by the deformation application unit 73. The attachment state determination unit 74 determines the presence or absence of an attachment defect of the sensor element 31 via the base film 32 to the bumper cover 22 based on the deformation voltage Vdg. The mounting state determination unit 74 outputs an H signal when it is detected that a mounting failure of the sensor element 31 to the bumper cover 22 has not occurred. Details of the method of deforming the base film 32 and the method of determining the presence or absence of the mounting failure of the sensor element 31 will be described later. Hereinafter, determining the presence or absence of a mounting defect of the sensor element 31 with respect to the bumper cover 22 is referred to as a mounting defect determination.

The three input ends of the AND circuit 75 are connected to the vehicle speed determination unit 71, the collision determination unit 72, and the attachment state determination unit 74. The AND circuit 75 outputs an H signal when all of the vehicle speed determination unit 71, the collision determination unit 72, and the attachment state determination unit 74 output an H signal.
The protection device driver 76 is connected to the output end of the AND circuit 75, and operates the cowl airbag device 51 or the pop-up hood 52 when the H signal is output from the AND circuit 75.

(Method of deformation of base film and method of determining mounting defect of sensor element)
Hereinafter, based on FIG. 6 and FIG. 7, the method of deforming the base film 32 by the deformation applying unit 73 and the method of determining the mounting defect of the sensor element 31 to the bumper cover 22 by the mounting state determination unit 74 will be described in detail. The deformation application unit 73 selects a plurality (or one) of the sensor elements 31 and indicates the selected sensor element 31S (shown by hatching in FIG. 6), hereinafter referred to as the deformation input element 31S. A predetermined drive voltage Vip is applied between the divided electrodes 31b and 31c included in the above to shrink the deformation input element 31S. The deformation input element 31S corresponds to a deformation input unit.

  As described above, since the base film 32 is fixed to the bumper cover 22 at the four corners CP, the base film 32 is deformed in the pulling direction by the contraction of the deformation input element 31S. Due to the deformation of the base film 32, a plurality of (or even one) sensor elements 31D (each corresponding to a detection cell, hereinafter referred to as a detection element 31D) adjacent to the deformation input element 31S are also deformed in the tensile direction A predetermined deformation voltage Vdg is generated between the divided electrodes 31b and 31c (shown in FIG. 7). The drive voltage Vip is not applied to the detection element 31D by the deformation application unit 73. The detection element 31D does not necessarily have to be adjacent to the deformation input element 31S, but the detection element 31D is at a distance from the deformation input element 31S within a range where the deformation voltage Vdg can be separated from electrical noise. May be

  The mounting state determination unit 74 stores a predetermined specified voltage Vfx. The prescribed voltage Vfx is generated in the detection element 31D when the drive voltage Vip is applied to the deformation input element 31S in a state where the sensor element 31 is normally attached to the bumper cover 22 via the base film 32. Deformation voltage Vdg. The state in which the sensor element 31 is normally attached to the bumper cover 22 via the base film 32 means that the base film 32 is normally attached to the bumper cover 22 and the sensor element 31 is in a state of being properly attached to the base film 32. The specified voltage Vfx is obtained in advance experimentally.

  On the other hand, when a mounting defect of the sensor element 31 to the bumper cover 22 occurs, the deformation voltage Vdg generated in the detection element 31D is defined even if the drive voltage Vip described above is applied to the deformation input element 31S. The value is different from the voltage Vfx. The poor attachment of the sensor element 31 to the bumper cover 22 is at least one of the peeling of the base film 32 to the bumper cover 22 and the peeling of the sensor element 31 to the base film 32.

For example, when the base film 32 is peeled off with respect to the bumper cover 22, even if the drive voltage Vip is applied to the deformation input element 31S, the base film 32 merely moves following the movement of the deformation input element 31S. The predetermined deformation does not occur in the base film 32. Therefore, the detection element 31D does not generate a predetermined deformation voltage Vdg.
On the other hand, when the deformation input element 31S is peeled off from the base film 32, deformation is not transmitted from the deformation input element 31S to the base film 32 even if the drive voltage Vip is applied to the deformation input element 31S. Further, when the detection element 31D is peeled from the base film 32, even if a predetermined deformation occurs in the base film 32, the deformation is not transmitted to the detection element 31D, and the detection element 31D is deformed in a predetermined manner. It does not generate voltage Vdg.
The attachment state determination unit 74 detects the sensor element 31 with respect to the bumper cover 22 when at least one of the plurality of detection elements 31D in which the generated deformation voltage Vdg is separated from the specified voltage Vfx by a predetermined amount is at least one. It is determined that a mounting failure has occurred.

  When the mounting defect determination is performed, the application of the drive voltage Vip to the deformation input element 31S and the deformation voltage Vdg generated in the detection element 31D while changing the deformation input element 31S and the detection element 31D to be selected in the sensor element 31 The detection may be repeated sequentially. The mounting failure determination of the base film 32 by the mounting state determination unit 74 may be performed at any timing. For example, as shown in FIG. 8, it may be performed each time the control flow routine, or may be performed immediately after the ignition switch of the vehicle VE is turned on, or while the ignition switch is turned on. The determination may be repeated at predetermined time intervals.

(Control method of pedestrian protection system)
Hereinafter, based on FIG. 8, the control method of the pedestrian protection system 1 by pedestrian protection ECU7 is demonstrated. First, the drive voltage Vip is applied to the deformation input element 31S by the deformation applying unit 73 (step S101).
Next, the attachment state determination unit 74 detects the deformation voltage Vdg generated in the detection element 31D (step S102).
Thereafter, the attachment state determination unit 74 determines whether or not the difference | Vdg-Vfx | between the detected deformation voltage Vdg and the specified voltage Vfx is less than or equal to the reference deviation ε for each of the plurality of detection elements 31D. (Step S103). The reference deviation ε is set to a predetermined positive value very close to zero.
When it is determined that the difference | Vdg−Vfx | between the deformation voltage Vdg and the prescribed voltage Vfx for at least one of the plurality of detection elements 31D is larger than the reference deviation ε, the bumper cover 22 of the sensor element 31 in the instrument panel 6 Is warned that a mounting failure has occurred (step S110), and this control flow ends. In this case, collision detection by the collision detection sensor 3 is not performed.

When it is determined that the difference | Vdg-Vfx | between the deformation voltage Vdg and the prescribed voltage Vfx is less than or equal to the reference deviation ε for all the detection elements 31D, the speed sensor 4 sends the vehicle speed determination unit 71 to the vehicle speed of the vehicle VE. The detected value Sdet is input (step S104).
Next, the vehicle speed determination unit 71 determines whether the vehicle speed detection value Sdet is equal to or greater than the first vehicle speed threshold Sth1 and equal to or less than the second vehicle speed threshold Sth2 (step S105).
When it is determined that the vehicle speed detection value Sdet is less than the first vehicle speed threshold Sth1 or exceeds the second vehicle speed threshold Sth2, the present control flow is ended. When it is determined that the vehicle speed detection value Sdet is equal to or greater than the first vehicle speed threshold Sth1 and equal to or less than the second vehicle speed threshold Sth2, the piezoelectric film voltage Vpz is input from the sensor element 31 toward the collision determination unit 72. (Step S106).

It is determined whether the piezo film voltage Vpz input to the collision determination unit 72 is equal to or higher than the voltage threshold Vth (step S107). The voltage threshold value Vth is set between the piezoelectric film voltage Vpz1 generated when the pedestrian or the bicycle collides with the bumper cover 22 and the piezoelectric film voltage Vpz2 generated when the ground workpiece collides.
If it is determined that the piezo film voltage Vpz is equal to or higher than the voltage threshold value Vth, it is detected in the bumper cover 22 that a collision requiring the operation of the pedestrian protection device 5 has occurred (step S108). The device 5 is operated (step S109).
When it is determined in step S107 that the piezo film voltage Vpz is less than the voltage threshold Vth, the present control flow ends.

<Operation and effect of Embodiment 1>
According to the present embodiment, the pedestrian protection system 1 includes the attachment state determination unit 74 that determines the presence or absence of the attachment failure of the sensor element 31 via the base film 32 to the bumper cover 22. The attachment state determination unit 74 is a mounting defect of the sensor element 31 to the bumper cover 22 based on the deformation voltage Vdg generated by the sensor element 31 when the base film 32 is deformed by the deformation application unit 73 and the prescribed voltage Vfx. The presence or absence of Thereby, the attachment defect of the sensor element 31 to the bumper cover 22 caused by at least one of the peeling of the base film 32 from the bumper cover 22 and the peeling of the sensor element 31 from the base film 32 is detected can do. Therefore, when a mounting defect of the sensor element 31 occurs, the driver of the vehicle VE can be warned and the operation of the pedestrian protection system 1 can be stopped, so that the pedestrian protection system 1 with high reliability can be obtained. Can be

  The deformation applying unit 73 applies the drive voltage Vip to the deformation input element 31S to deform the base film 32 using the deformation input element 31S. The attachment state determination unit 74 determines the attachment defect of the sensor element 31 to the bumper cover 22 based on the deformation voltage Vdg generated in the detection element 31D to which the drive voltage Vip is not applied. As a result, the mounting defect of the sensor element 31 can be determined using only the sensor element 31 for detecting a collision, and a special actuator or the like for deforming the base film 32 is necessary for the determination of the mounting defect. And never.

The detection element 31D whose deformation voltage Vdg is detected by the attachment state determination unit 74 is adjacent to the deformation input element 31S to which the drive voltage Vip is applied by the deformation application unit 73. Thereby, the deformation of the base film 32 generated by the deformation input element 31S can be easily detected, and the mounting defect determination of the sensor element 31 on the bumper cover 22 can be performed with high accuracy.
The base film 32 has a rectangular shape, and is attached to the bumper cover 22 at its four corners CP. Thereby, the attachment process of the base film 32 to the bumper cover 22 can be simplified. In addition, since the base film 32 can be deformed at portions other than the four corners CP, the range in which the deformation input element 31S can be arranged can be widened on the base film 32.

<Configuration of First Modification>
Hereinafter, based on FIG. 9, the attachment method to the bumper cover 22 of the collision detection sensor 3 by the 1st modification of Embodiment 1 is demonstrated. In FIG. 9, the overall length in the left-right direction of the collision detection sensor 3 is schematically shown shorter than in actuality. As in the first embodiment, the base film 32 according to the present modification has a rectangular shape, and the bumper cover 22 is provided at the peripheral fixing portion FP (corresponding to the peripheral portion) which is a portion to which the sensor element 31 is not joined. Is attached to As shown in FIG. 9, the peripheral fixing portion FP includes the upper edge, the lower edge, and the left and right edges of the base film 32, and the base film 32 has an outer peripheral portion with respect to the bumper cover 22. It is fixed all around. The other configuration of the collision detection sensor 3 is the same as that of the first embodiment, and thus the description thereof will be omitted.

<Operation and effect of first modification>
According to this modification, the base film 32 has a rectangular shape, and is attached to the bumper cover 22 at the peripheral fixing portion FP. Thus, the base film 32 can be firmly attached to the bumper cover 22. In addition, deformation can be applied to the base film 32 at any position of the portion surrounded by the peripheral edge fixing portion FP, and the mounting defect determination of the sensor element 31 can be easily performed.

<Configuration of Second Modification>
Hereinafter, based on FIG. 10, the attachment method to the bumper cover 22 of the collision detection sensor 3 by the 2nd modification of Embodiment 1 is demonstrated. In FIG. 10, the overall length in the left-right direction of the collision detection sensor 3 is schematically shown shorter than in actuality. Also in this modification, the base film 32 has a rectangular shape as in the first embodiment, and the plurality of sensor elements 31 are arranged on the base film 32 so as to form columns and rows.

  The base film 32 has a bumper at a position corresponding to the inter-row fixing portion BP between adjacent rows of the sensor elements 31 and an end fixing portion OP which is an upper and lower end portion where the sensor element 31 is not joined. It is attached to the cover 22. The corresponding position is that while the sensor element 31 is attached to the surface 32 a on one side of the base film 32, the base film 32 is joined to the bumper cover 22 as follows: This is because the other side 32b is not in the same plane. The base film 32 may be attached to the bumper cover 22 at a corresponding position between adjacent columns of the sensor element 31. The other configuration of the collision detection sensor 3 is the same as that of the first embodiment, and thus the description thereof will be omitted.

<Operation and effect of the second modification>
According to this modification, the base film 32 is attached to the bumper cover 22 at a position corresponding to the inter-row fixing portion BP between adjacent rows of the sensor element 31. Thereby, the attachment position with respect to the bumper cover 22 can be equally provided on the base film 32, and the collision generated in the bumper cover 22 can be accurately detected by the collision detection sensor 3. Further, by using the sensor elements 31 adjacent in the lateral direction as the deformation input element 31S and the detection element 31D, the deformation of the base film 32 given by the deformation input element 31S is accurately detected by the detection element 31D. can do.

<Configuration of Embodiment 2>
The collision detection sensor 3A according to the second embodiment will be described below based on FIG. In FIG. 11, the overall length in the left-right direction of the collision detection sensor 3A is schematically shown shorter than in actuality. As in the first embodiment, the base film 32 according to the present embodiment has a substantially rectangular shape, and is joined to the bumper cover 22 at its four corners CP. A plurality of actuator metal pieces 33 (corresponding to a deformation input unit) are formed on the base film 32. As shown in FIG. 11, each actuator metal piece 33 is disposed between adjacent rows of sensor elements 31. As indicated by broken lines in FIG. 11, the actuator metal pieces 33 may be disposed between adjacent columns of the sensor element 31 instead of between the rows.

  Each actuator metal piece 33 is formed of a shape memory alloy, and is fixed to the base film 32 over the entire length thereof. The deformation applying unit 73 applies a current to the actuator metal piece 33 to generate heat instead of deforming the substrate film 32 by the sensor element 31, and deforms the substrate film 32 by deforming the actuator metal piece 33. ing. The attachment state determination unit 74 mounts the sensor element 31 to the bumper cover 22 based on the deformation voltage Vdg generated in any of the sensor elements 31 when a current is applied to the actuator metal piece 33 by the deformation application unit 73. Execute defect judgment. Even if the actuator metal pieces 33 are respectively disposed between adjacent columns of the sensor elements 31, they function in the same manner as described above. The other configuration of the present embodiment and the method of determining the attachment defect of the sensor element 31 to the bumper cover 22 according to the present embodiment are the same as in the case of the first embodiment, and thus further description will be omitted.

<Operation and effect of Embodiment 2>
According to the present embodiment, the actuator metal piece 33 provided on the base film 32 is supplied with current to generate heat, and the base film 32 is deformed together with the actuator metal piece 33. As a result, the sensor element 31 is not used to deform the base film 32, and the mounting defect determination does not affect the function of the sensor element 31. Therefore, the mounting defect determination of the sensor element 31 can be performed without disturbing the collision detection of the bumper cover 22.
Each actuator metal strip 33 is disposed between adjacent rows of sensor elements 31. Thereby, it is possible to prevent the influence on the arrangement and the shape of the sensor element 31 on the base film 32.

<Configuration of Embodiment 3>
Hereinafter, the collision detection sensor 3B according to the third embodiment will be described based on FIGS. 12 and 13. In FIG. 12, the overall length in the left-right direction of the collision detection sensor 3B is schematically shown shorter than in actuality. The collision detection sensor 3B according to the present embodiment includes a sensor element 34 (corresponding to a collision sensor) and a base film 32. As shown in FIG. 12, unlike the first embodiment, the sensor element 34 is not divided into a plurality but integrally formed. The sensor element 34 includes a piezoelectric polymer film 34a (corresponding to a piezoelectric film) and a flat plate-like first electrode 34b and a second electrode 34c (both of which are a pair of electrodes) sandwiching both sides of the piezoelectric polymer film 34a. (Corresponding to FIG. 13). The sensor element 34 generates a predetermined piezo film voltage Vpz between the first electrode 34 b and the second electrode 34 c according to the generated deformation.

  The base film 32 similar to that of Embodiment 1 is bonded to the surface of the second electrode 34c not attached to the piezoelectric polymer film 34a on the surface 32a on one side thereof. The sensor element 34 is bonded to the base film 32 by an adhesive or a double-sided adhesive tape. The other surface 32 b of the base film 32 is attached to the back surface 22 a of the bumper cover 22. As in the first embodiment, the base film 32 has a substantially rectangular shape, and is joined to the bumper cover 22 at its four corners CP.

  A deformation input device 35 (corresponding to a deformation input portion) is connected to the upper end portion input point UP formed at the upper edge portion and the side end portion input point SP formed at the right side portion of the base film 32. ing. The upper end input point UP and the side end input point SP are formed at positions different from the four corners CP. The deformation input device 35 is formed by an electromagnetic actuator or an electrostatic actuator. The deformation input device 35 may be formed of a piezoelectric element or a shape memory alloy. The deformation applying unit 73 deforms the base film 32 by the deformation input device 35 instead of deforming the base film 32 by the sensor element 31. The deformation application unit 73 operates the deformation input device 35 to pull the upper end input point UP of the base film 32 upward or pull the side end input point SP to the right.

  When the base film 32 is pulled by the deformation input device 35, the attachment state determination unit 74 determines the attachment defect of the sensor element 34 to the bumper cover 22 based on the deformation voltage Vdg generated in the sensor element 34. . The deformation input device 35 may be connected to only one of the upper end input point UP and the side end input point SP. Also, the deformation input device 35 may be connected to the lower edge or the left side of the base film 32. Furthermore, the sensor element 34 may be divided into a plurality of sensor elements 31 as in the first embodiment. The other configuration of the present embodiment and the method of determining the attachment defect of the sensor element 31 to the bumper cover 22 according to the present embodiment are the same as those of the first embodiment, and thus further description will be omitted.

Other Embodiments
The present invention is not limited to the embodiments described above, and can be modified or expanded as follows.
When the mounting defect determination of the sensor element 31 on the bumper cover 22 is performed, the base film 32 does not necessarily have to be deformed in the pulling direction. The substrate film 32 may be deformed in the compression direction, and the generated deformation voltage Vdg may be detected to determine the mounting defect of the sensor element 31.
In the second embodiment, the actuator metal piece 33 may be attached to the peripheral portion of the base film 32, and the integrally formed sensor element 34 similar to that of the third embodiment may be bonded to the base film 32.

  In the drawing, 1 is a pedestrian protection system (collision detection device for vehicles), 5 is a pedestrian protection device (protection device), 22 is a bumper cover, 22a is a back surface (inner side of bumper cover), 31 is a sensor element (collision Sensor, sensor cell), 31a is a piezoelectric polymer film (piezoelectric film, divided piezoelectric film), 31b is a first divided electrode (electrode, divided electrode), 31c is a second divided electrode (electrode, divided electrode), 31D is detected Element (detection cell) 31S: deformation input element (any sensor cell, deformation input part) 32: base film 33: actuator metal piece (shape memory alloy, deformation input part) 34: sensor element (collision sensor , 34a is a piezoelectric polymer film (piezoelectric film), 34b is a first electrode (electrode), 34c is a second electrode (electrode), 35 is a deformation input device (deformation input unit), 7 The collision determination unit, 73 modification applying unit (changed input unit) 74 attached state determination unit, VE represents the vehicle.

Claims (8)

A piezoelectric film (31a, 34a) and a pair of flat plate electrodes (31b, 31c, 34b, 34c) sandwiching both sides of the piezoelectric film, and a predetermined output signal (Vpz) between the electrodes according to the generated deformation. Collision sensor (31, 34) to generate
A substrate film (32) interposed between the collision sensor and an inner surface (22a) of a bumper cover (22) of a vehicle (VE);
A collision determination unit (72) that detects that a collision requiring the operation of a protection device (5) for protecting a collision object has occurred in the bumper cover based on the output signal formed by the collision sensor When,
Collision detection apparatus (1) for vehicles provided with
A deformation input unit (31S, 33, 35, 73) that inputs a load to a portion (UP, SP) of the base film not joined to the bumper cover, and deforms the base film;
The output signal a is deformed signal (Vdg), said collision sensor is mounted correctly through the Kimotozai film previous to said bumper cover that occurs when the base film is deformed by the deformation input unit An attachment state determination unit (74) that determines the presence or absence of an attachment failure of the collision sensor to the bumper cover based on a predefined signal (Vfx) defined in advance as the deformation signal generated in the state of
Collision detection device for vehicles. The collision sensor is
Divided into a plurality of sensor cells (31) each having a split piezoelectric film (31a) and a pair of split electrodes (31b, 31c) sandwiching both sides of the split piezoelectric film,
The base film is
By being joined to one of the divided electrodes (31c) included in each of the sensor cells, adjacent ones of the plurality of sensor cells are held apart from each other,
The deformation input unit is
Applying a voltage to the divided electrodes included in any of the sensor cells (31S) to deform the base film using the sensor cells;
The attachment state determination unit
The sensor cell is normally attached via the base film to the deformation signal generated in the detection cell (31D) which is the sensor cell to which a voltage is not applied by the deformation input unit and the bumper cover The collision detection apparatus for vehicles according to claim 1 which judges existence of poor attachment of said collision sensor to said bumper cover based on said modification signal which occurred in said detection cell when it has.   The vehicle collision detection device according to claim 2, wherein the detection cell is adjacent to the sensor cell to which a voltage is applied by the deformation input unit. A plurality of said sensor cells are arranged to form columns and rows on said substrate film,
The base film is attached to the bumper cover at a position corresponding to any one of the adjacent columns of the sensor cells and the adjacent rows (BP) of the sensor cells. The collision detection device for vehicles according to or 3. The deformation input unit is
Comprising a shape memory alloy (33) mounted on the substrate film,
The collision detection device for vehicles according to claim 1 which makes a current generate heat in said shape memory alloy, and makes said base film deform with said shape memory alloy. The collision sensor is
A plurality of sensor cells (31) each including a split piezoelectric film (31a) and a pair of split electrodes (31b, 31c) sandwiching both sides of the split piezoelectric film;
The base film is
A plurality of sensor cells are arranged to form columns and rows by being joined to one of the divided electrodes (31 c) of each of the sensor cells, and the sensor cells are held such that adjacent ones are separated from each other Yes,
The shape memory alloy is
Arranged between adjacent ones of the columns of the sensor cells or between adjacent ones of the rows;
The attachment state determination unit
When the current is applied to the shape memory alloy, the sensor cell is normally attached via the base film to the deformation signal generated in one of the sensor cells and the bumper cover. The collision detection device for vehicles according to claim 5 which judges existence of poor attachment of said collision sensor to said bumper cover based on said modification signal in a case.   The collision detection device for vehicles according to any one of claims 1 to 6, wherein the base film has a rectangular shape and is attached to the bumper cover at four corners (CP).   The collision detection apparatus for vehicles according to any one of claims 1 to 6, wherein the base film has a rectangular shape, and a peripheral portion (FP) is attached to the bumper cover.

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