JP2017030721A - Vehicle collision detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle collision detecting apparatus which may accurately detect occurrence of collision onto a vehicle and which may be easily assembled.SOLUTION: A piezo film 31 covered by sensor housing 32 is attached onto backside 22a of a bumper cover 22 of a vehicle. The sensor housing 32 has a rigidity stronger than the piezo film 31 and has predetermined flexibility. The sensor housing 32 is fixed onto the bumper cover 22 with adhesive agent etc. in a state where it supports the piezo film 31. When collision onto bumper cover 22 occurs, the sensor housing 32 is deformed together with the bumper cover 22 so that the piezo film 31 generates piezo film voltage Vpz. In a case where piezo film voltage Vpz generated by the piezo film 31 is larger than a predetermined voltage threshold Vth, a collision determining part determines occurrence of collision to the bumper cover 22 where a walker protecting apparatus should work.SELECTED DRAWING: Figure 2

Description

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

  There has been a conventional technology related to a vehicle collision detection device that provides a shock absorber behind the bumper cover, disposes a detection tube between the shock absorber and the cross member, and detects a pedestrian collision with the front end of the vehicle ( For example, see Patent Document 1). The collision detection device according to the related art is intended to enable detection of a collision with respect to a wide area in the bumper cover. In this prior art, when a pressure exceeding a threshold value is generated in a detection tube that extends long in the vehicle width direction, it is detected that a pedestrian has collided with the bumper cover.

Special table 2014-505629 gazette

However, in the vehicle collision detection device, since the collision to the front end of the vehicle is detected via the buffer, when the collision occurs in the bumper cover at the front end of the vehicle, the shock caused by the collision is the buffer. Attenuates while propagating to For this reason, for example, when the impact due to the collision is small, the detection tube disposed behind the buffer cannot accurately detect the pressure increase due to the impact due to the collision.
Further, in the above-described conventional vehicle collision detection device, it is necessary to arrange the detection tube so as to extend in the vehicle width direction without dropping from the buffer body, which is an impediment to the efficiency of assembly work. It was.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle collision detection device that can accurately detect that a collision with a vehicle has occurred and can be easily assembled. .

  In order to solve the above-described problem, the invention of the vehicle collision detection device according to claim 1 is a piezoelectric polymer film that generates a predetermined output voltage by being deformed, and is more rigid than the piezoelectric polymer film. A film support that includes a support wall that supports at least one surface of the piezoelectric polymer film, is attached to an inner surface of a bumper cover provided at a front portion of the vehicle, and is deformable together with the bumper cover; A collision that detects the occurrence of a collision on the bumper cover that requires the operation of a protective device that protects the collision object, based on the output voltage generated by the piezoelectric polymer film according to the deformation amount of the bumper cover. And a determination unit.

According to this structure, the piezoelectric polymer film which generates the output voltage according to the deformation amount of the bumper cover is provided. And the collision determination part has detected that the collision generate | occur | produced in the bumper cover of the vehicle based on the output voltage formed with the piezoelectric polymer film. Accordingly, it is possible to accurately detect that a collision has occurred in the bumper cover of the vehicle based on the output voltage that directly affects the deformation amount of the bumper cover.
The piezoelectric polymer film is supported by a more rigid film support, and the film support is attached to the bumper cover. For this reason, the thin film-like piezoelectric polymer film can be easily assembled to the vehicle, and the vehicle collision detection device can be easily manufactured.
The vehicle collision detection apparatus according to the present invention is not intended for detection of only pedestrian collisions, but for all collision detections that require the pedestrian protection apparatus to be activated.

The top view of the vehicle with which the pedestrian protection system by Embodiment 1 of this invention was attached. II-II sectional view of FIG. Diagram showing the back view of the sensor unit Block diagram showing the configuration of the pedestrian protection system The figure which showed the control flowchart of a pedestrian protection system FIG. 5 is an exploded cross-sectional view of a sensor unit according to a first modification of the first embodiment. Sectional drawing showing the assembled state of the sensor unit shown in FIG. 6A FIG. 6 is an exploded cross-sectional view of a sensor unit according to a second modification of the first embodiment. Sectional drawing showing the assembled state of the sensor unit shown in FIG. 7A Sectional drawing at the time of cutting the front part of the vehicle by Embodiment 2 in the front-back direction The figure showing the back view of the sensor unit shown in FIG. FIG. 8 is an enlarged sectional view showing a different fastening method for the fastening part shown in the IXB part of FIG. The figure showing the back view of the sensor unit by Embodiment 3. XIA-XIA cross section of FIG. Sectional drawing showing the state which attached the sensor unit shown to FIG. 11A to the bumper cover Sectional drawing at the time of cutting the sensor unit by the modification of Embodiment 3 in the front-back direction Sectional drawing showing the state which attached the sensor unit shown to FIG. 12A to the bumper cover XIIC-XIIC cross section of Fig. 12B Sectional drawing at the time of cutting the state which attached the clearance sonar by Embodiment 4 to the bumper cover in the horizontal direction 13A is an enlarged cross-sectional view illustrating the XIIIB portion of FIG. Exploded sectional view of a sensor unit according to Embodiment 5 Sectional drawing showing the assembled state of the sensor unit shown in FIG. 14A Sectional drawing at the time of cutting the sensor unit by Embodiment 6 horizontally Sectional drawing showing the state which attached the sensor unit shown to FIG. 15A to the bumper cover Sectional drawing showing the state which attached the sensor unit by the modification of Embodiment 6 to the bumper cover. The top view of the sensor unit by Embodiment 7 XVIIA-XVIIA sectional view of FIG. XVIIB-XVIIB sectional view of FIG. The figure which showed the graph showing the output characteristic of the sensor unit by Embodiment 7 The figure which showed the graph showing the output characteristic of the sensor unit as a comparative example Sectional drawing at the time of cut | disconnecting the sensor unit by the 1st modification of Embodiment 7 perpendicularly | vertically with respect to the vehicle width direction in the center shown in FIG. Sectional drawing at the time of cutting the sensor unit by the 1st modification of Embodiment 7 in the corner part shown in FIG. In the sensor housing by the 2nd modification of Embodiment 7, the schematic diagram which showed a part of outer peripheral surface by a 1st pattern The schematic diagram which showed a part of outer peripheral surface by the 2nd pattern of a sensor housing The schematic diagram which showed a part of outer peripheral surface by the 3rd pattern of a sensor housing

  Hereinafter, Embodiments 1 to 7 of the present invention will be described. In addition, the description which shows the direction in description and FIG. 1 thru | or FIG. 19B shall correspond with the direction for the driver | operator who seated on the vehicle VE. For example, in FIG. 1 to FIG. 19B, the indication “front” indicates that the direction of the arrow corresponds to the front of the vehicle VE. In the following, the description will focus on the collision of a pedestrian with respect to the vehicle VE, but the vehicle collision detection device according to the present invention is not only intended for detection of a pedestrian collision, but a pedestrian such as a bicycle or a stroller. All collision detections that require the protection device 5 to operate are intended.

<Configuration of Embodiment 1>
A pedestrian protection system 1 (corresponding to a vehicle collision detection apparatus) according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 5.
(Overall configuration of pedestrian protection system)
As shown in FIG. 1, a front bumper 21 (corresponding to a front portion of the vehicle) is attached to the front end portion 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 in the front portion of the vehicle VE. The bumper absorber 23 is provided behind the bumper cover 22 as an impact absorbing material when a collision occurs in the front bumper 21. The bumper absorber 23 is made of a foamed resin such as foamed polypropylene, for example.

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

  As shown in FIGS. 1 and 2, the sensor unit 3 is attached to the rear surface 22 a (corresponding to the inner surface of the bumper cover) which is the rear surface of the bumper cover 22. The sensor unit 3 is desirably mounted at a height at which a pedestrian or the like collides on the vehicle VE. As shown in FIGS. 2 and 3, in the sensor unit 3, the entire outer peripheral surface of the piezo film 31 (corresponding to the piezoelectric polymer film) is covered with the sensor housing 32 (corresponding to the film support). It is formed by. The piezo film 31 is integrally formed with the sensor housing 32 by insert molding or the like. The sensor unit 3 extends in the vehicle width direction (lateral direction) so as to connect both ends of the bumper cover 22 (shown in FIG. 1).

  The piezo film 31 included in the sensor unit 3 is formed by sandwiching a piezo element formed in a thin film shape with a pair of electrodes (not shown) made of a metal film. The piezoelectric element is made of a piezoelectric polymer material such as polyvinylidene fluoride (PVDF), polypeptide, polylactic acid, polymethylglutamate, or polybenzylglutamate. When the bumper cover 22 is deformed by the collision, a tensile stress or a compressive stress is applied to the piezoelectric film 31 due to the deformation, and a predetermined output voltage (hereinafter referred to as a piezoelectric film voltage Vpz) corresponding to the deformation amount Q of the bumper cover 22 is applied between the electrodes. Say). Piezo films themselves are known, and are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-96980, 2007-212436, and 2013-29368, which are publicly known patent publications. Instead of the piezo film 3, the pyroelectric body (pyro) film may be covered with the sensor housing 32 to form the sensor unit 3.

  The sensor housing 32 is formed of a synthetic resin material or a synthetic rubber material such as polypropylene, polyethylene, elastomer, EPDM (Ethylene Propylene Diene Monomer), or silicon rubber. The sensor housing 32 is more rigid than the piezo film 31 and has a predetermined flexibility. The sensor housing 32 has a pair of support walls 32 a and 32 b that respectively support both surfaces of the piezo film 31. The sensor housing 32 is fixed to the bumper cover 22 with an adhesive or the like while supporting the piezo film 31. Further, the sensor housing 32 can be deformed following the shape of the bumper cover 22 when attached to the bumper cover 22. Further, the sensor housing 32 is formed so as to be deformable together with the bumper cover 22 at the time of collision with the front bumper 21. The sensor housing 32 may be formed of a material other than those listed above as long as it can satisfy predetermined rigidity and deformability.

Returning to FIG. 1, the speed sensor 4 provided in the vehicle VE is attached to a wheel or a 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 a protection device). When a pedestrian collides with the front bumper 21, the cowl airbag device 51 deploys a bag from the engine hood HE shown in FIG. 1 to the lower part of the front window WF, and protects colliding objects such as a pedestrian colliding.
A 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, preventing a pedestrian from colliding with a rigid member such as an engine, and protecting colliding objects such as a colliding pedestrian.

(Configuration of pedestrian protection ECU)
In the vehicle VE, a pedestrian protection ECU 6 is mounted on a floor tunnel in front of the driver's seat (not shown). The pedestrian protection ECU 6 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 piezo film 31, the speed sensor 4, the cowl airbag device 51, and the pop-up hood 52 are connected to the pedestrian protection ECU 6 by communication lines.

As shown in FIG. 4, the pedestrian protection ECU 6 includes a vehicle speed determination unit 61, a collision determination unit 62, an AND circuit 63, and a protection device driver 64.
The vehicle speed determination unit 61 is connected to the speed sensor 4. The vehicle speed determination unit 61 determines whether the vehicle speed detection value Sdet by the speed sensor 4 is equal to or greater than a predetermined first vehicle speed threshold value Sth1 and equal to or less than a predetermined second vehicle speed threshold value Sth2. The vehicle speed determination unit 61 outputs a high (H) signal when the vehicle speed detection value Sdet is not less than the first vehicle speed threshold value Sth1 and not more than the second vehicle speed threshold value Sth2.
The collision determination unit 62 is connected to the piezo film 31. The collision determination unit 62 compares the piezo film voltage Vpz input from the piezo film 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 62 detects that a collision that requires the operation of the pedestrian protection device 5 has occurred in the bumper cover 22 and outputs an H signal. In addition, for reasons of arithmetic processing, when a predetermined detection voltage is formed based on the piezo film voltage Vpz and the detection voltage is equal to or higher than the voltage threshold Vth, the collision determination unit 62 activates the pedestrian protection device 5. It may be determined that a necessary collision has occurred.
A pair of input ends of the AND circuit 63 is connected to the vehicle speed determination unit 61 and the collision determination unit 62. The AND circuit 63 outputs an H signal when the vehicle speed determination unit 61 outputs an H signal and the collision determination unit 62 outputs an H signal.
The protection device driver 64 is connected to the output terminal of the AND circuit 63 and operates the cowl airbag device 51 or the pop-up hood 52 when the H signal is output from the AND circuit 63.

(Control method for pedestrian protection system)
Hereinafter, based on FIG. 5, the control method of the pedestrian protection system 1 by pedestrian protection ECU6 is demonstrated. First, the vehicle speed detection value Sdet of the vehicle VE is input from the speed sensor 4 to the vehicle speed determination unit 61 (step S101). Next, the vehicle speed determination unit 61 determines whether or not the vehicle speed detection value Sdet is greater than or equal to the first vehicle speed threshold Sth1 and less than or equal to the second vehicle speed threshold Sth2 (step S102). When it is determined that the vehicle speed detection value Sdet is less than the first vehicle speed threshold value Sth1 or exceeds the second vehicle speed threshold value Sth2, this control flow ends. 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 piezo film voltage Vpz is input from the piezo film 31 toward the collision determination unit 62. (Step S103).

  It is determined whether or not the piezo film voltage Vpz input to the collision determination unit 62 is equal to or higher than the voltage threshold Vth (step S104). The voltage threshold Vth is set between a piezo film voltage Vpz that is generated when a pedestrian or a bicycle collides with the bumper cover 22 and a piezo film voltage Vpz that is generated when a ground workpiece collides. When it is determined that the piezo film voltage Vpz is equal to or higher than the voltage threshold Vth, the bumper cover 22 detects that a collision requiring the operation of the pedestrian protection device 5 has occurred (step S105), and protects the pedestrian. The device 5 is activated (step S106). If it is determined in step S104 that the piezo film voltage Vpz is less than the voltage threshold value Vth, this control flow ends.

<Effect of Embodiment 1>
According to the present embodiment, the piezoelectric film 31 that generates the piezoelectric film voltage Vpz corresponding to the deformation amount Q of the bumper cover 22 is provided. Then, the collision determination unit 62 detects that a collision has occurred in the bumper cover 22 of the vehicle VE based on the piezo film voltage Vpz formed by the piezo film 31. Accordingly, it is possible to accurately detect that a collision has occurred in the bumper cover 22 of the vehicle VE, based on the piezo film voltage Vpz that is directly affected by the deformation amount Q of the bumper cover 22.
Further, it is not necessary to provide a pressure detection tube in the bumper absorber 23, and the pedestrian protection system 1 that is easy to manufacture can be obtained.

  Further, since the piezo film 31 is a thin film sensor, there is a problem that it is greatly deformed only by its own weight and is difficult to handle. Furthermore, since it is a thin film, when attaching to the bumper cover 22, there exists a subject that the intensity | strength holding fastening members, such as a volt | bolt and a clip, cannot be ensured. On the other hand, in this embodiment, the piezo film 31 is supported by the sensor housing 32 having higher rigidity. For this reason, handling property at the time of carrying the thin film-like piezo film 31 and attaching to the vehicle VE is improved, and the piezo film 31 can be easily attached to the bumper cover 22. Further, by attaching the sensor housing 32 supporting the piezo film 31 to the bumper cover 22, it is possible to ensure sufficient strength to hold a bolt or the like for attachment. Furthermore, the piezo film 31 can be prevented from being damaged during the mounting operation, and the reliability of the pedestrian protection system 1 can be increased.

Further, since the piezo film 31 is integrally formed with the sensor housing 32, the forming process of the sensor housing 32 and the assembling process of the sensor unit 3 can be integrated, and the sensor unit 3 is easily formed. be able to.
The sensor housing 32 includes support walls 32a and 32b that support both surfaces of the piezo film 31, respectively. Thereby, damage of the piezo film 31 at the time of attachment work can be prevented, and attachment workability to the vehicle VE can be improved.
In addition, since the entire outer peripheral surface of the piezo film 31 is covered with the sensor housing 32, waterproofness, insulation, and dustproofness with respect to the piezo film 31 can be improved.
The sensor housing 32 is formed so as to be deformable following the shape of the bumper cover 22 when attached to the bumper cover 22. Thereby, irrespective of the shape of the back surface 22a of the bumper cover 22, the adhesion between the sensor housing 32 and the bumper cover 22 can be ensured, and the holding force of the sensor housing 32 by the bumper cover 22 can be increased. it can.

<Configuration of First Modification of First Embodiment>
Hereinafter, based on FIG. 6A and FIG. 6B, a sensor unit 3 </ b> A according to a first modification of the first embodiment will be described. In the present embodiment, a sensor housing 32A (corresponding to a film support) included in the sensor unit 3A is formed of a pair of first housing piece 33a and second housing piece 33b that are fitted to each other. Hereinafter, the first housing piece 33a and the second housing piece 33b are collectively referred to as housing pieces 33a and 33b (corresponding to a pair of support pieces).
The housing pieces 33a and 33b are formed separately, and a piezo film 31 is interposed between the housing pieces 33a and 33b (corresponding to support pieces). The housing pieces 33a and 33b have support walls 33a1 and 33b1 that support both sides of the piezo film 31, respectively. The housing pieces 33a and 33b are coupled to each other by press-fitting, fitting, snap-fit, adhesion, welding, etc. with the piezo film 31 interposed therebetween, and cover the entire outer peripheral surface of the piezo film 31 (see FIG. 6B). Since other configurations of the sensor unit 3A are the same as those of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Operational effects of the first modification>
According to this modification, the sensor housing 32A is formed by a pair of housing pieces 33a and 33b joined together, and the piezo film 31 is interposed between the housing pieces 33a and 33b. Accordingly, the sensor unit 3A can be formed without integrally forming the piezo film 31 and the housing pieces 33a and 33b. For this reason, the mold structure for forming the housing pieces 33a and 33b can be simplified.

<Configuration of Second Modification of First Embodiment>
Hereinafter, based on FIG. 7A and FIG. 7B, the sensor unit 3B by the 2nd modification of Embodiment 1 is demonstrated. The sensor housing 32B (corresponding to the film support) included in the sensor unit 3B is formed by joining the first housing piece 33c and the second housing piece 33d in the same manner as the sensor unit 3A according to the first modification. Has been. A piezo film 31 is sandwiched between the first housing piece 33c and the second housing piece 33d, and the sensor housing 32B covers the entire outer peripheral surface of the piezo film 31 (shown in FIG. 7B). Hereinafter, the first housing piece 33c and the second housing piece 33d are collectively referred to as housing pieces 33c and 33d (corresponding to a pair of support pieces).

  The first housing piece 33 c (corresponding to one of the support pieces) has a support wall 33 c 1 that supports one surface of the piezo film 31. Unlike the sensor unit 3A, the first housing piece 33c has a pair of upper and lower holding pieces 33c2 (corresponding to a holding portion) formed so as to face the support wall 33c1. Each holding piece 33c2 holds the piezo film 31 together with the support wall 33c1. Since the piezo film 31 is formed of a thin film and has flexibility, the piezo film 31 can be inserted from the periphery between the holding piece 33c2 and the support wall 33c1 and held by both. The shape and size of the holding piece 33c2 and the number provided in the first housing piece 33c are not limited to this modification, and can be freely set according to the required holding force of the piezo film 31 and the like. Is possible. On the other hand, the second housing piece 33 d has a support wall 33 d 1 that supports the other surface of the piezo film 31. Since the other configuration of the sensor unit 3B is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<The effect of the 2nd modification of Embodiment 1>
According to this modification, the first housing piece 33c is formed to be in contact with one surface of the piezo film 31, and to be opposed to the support wall 33c1, and to hold the piezo film 31 together with the support wall 33c1. 33c2. Accordingly, the piezoelectric film 31 can be held only by the first housing piece 33c before the housing pieces 33c and 33d are joined together. Therefore, workability at the time of joining the first housing piece 33c and the second housing piece 33d can be improved.

<Configuration of Embodiment 2>
Hereinafter, the sensor unit 3C according to the second embodiment will be described with reference to FIGS. 8, 9A, and 9B. The sensor unit 3C according to the present embodiment is formed by integrally forming a piezo film 31 with respect to a sensor housing 32C (corresponding to a film support), similarly to the sensor unit 3 according to the first embodiment (see FIG. 8). ). The entire outer peripheral surface of the piezo film 31 is covered with a sensor housing 32C. The sensor housing 32 </ b> C extends in the vehicle width direction so as to connect both ends of the bumper cover 22. The sensor housing 32C has a pair of support walls 32C3 and 32C4 that respectively support both surfaces of the piezo film 31. A material similar to that of the sensor housing 32 according to the first embodiment is applied to the sensor housing 32C, which is more rigid than the piezo film 31 and has a predetermined flexibility. The sensor housing 32 </ b> C can be deformed following the shape of the bumper cover 22 when attached to the bumper cover 22. Further, the sensor housing 32 </ b> C is formed to be deformable together with the bumper cover 22 at the time of collision with the front bumper 21.

  As shown in FIG. 9A, a plurality of fixed pieces 32C1 protruding upward are formed at the upper end of the sensor housing 32C. The fixed pieces 32C1 are formed so as to be arranged in the vehicle width direction at equal intervals. Also at the lower end of the sensor housing 32C, a plurality of fixed pieces 32C1 protrude downward, and the fixed pieces 32C1 are formed at equal intervals in the vehicle width direction. A mounting hole 32C2 passes through each of the fixed pieces 32C1 formed at the upper end and the lower end of the sensor housing 32C. Each mounting hole 32C2 is formed as a long hole extending in the vehicle width direction.

As shown in FIG. 8, a recess 22b is formed on the back surface 22a of the bumper cover 22, and the peripheral portion of the sensor unit 3C described above is fitted therein. Fastening pins 34 (corresponding to fastening members) are inserted into the mounting holes 32C2 formed in the fixed piece 32C1 of the sensor housing 32C. The fastening pin 34 is made of a synthetic resin material or metal. The fastening pin 34 penetrating through the mounting hole 32C2 is fixed to the fixing hole 22c formed on the back surface 22a of the bumper cover 22 by press fitting, welding, screwing, or the like. Thereby, the sensor housing 32 </ b> C is attached to the bumper cover 22.
As described above, each attachment hole 32C2 is formed as a long hole extending in the vehicle width direction. For this reason, when the sensor housing 32C is attached to the bumper cover 22, the variation in the position in the vehicle width direction between the fixing hole 22c of the bumper cover 22 and the attachment hole 32C2 of the sensor housing 32C is absorbed by the elongated hole. Is made possible. The shape, size, and number of the fixing pieces 32C1 and the mounting holes 32C2 are not limited to the present embodiment, and can be freely set according to the space around the sensor unit 3C, the required holding force for the bumper cover 22, and the like. It is possible.

  The attachment structure of the sensor housing 32C to the bumper cover 22 may be configured as shown in FIG. 9B. In FIG. 9B, a fastening protrusion 22 d protrudes rearward from the back surface 22 a of the bumper cover 22. When the sensor housing 32C is attached to the bumper cover 22, the fastening protrusion 22d formed on the bumper cover 22 is inserted into the attachment hole 32C2, and the distal end of the fastening protrusion 22d protruding from the attachment hole 32C2 (projecting from the attachment hole). Fastening plug 35 is fixed to the corresponding part). Thereby, the sensor housing 32 </ b> C is attached to the bumper cover 22. The fastening plug 35 is fixed to the fastening projection 22d by heat welding or the like. Since the other configuration of the sensor unit 3C is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Effects of Second Embodiment>
According to the present embodiment, the sensor housing 32C has the mounting hole 32C2 extending therethrough, and the fastening pin 34 passed through the mounting hole 32C2 is fixed to the bumper cover 22, whereby the sensor housing 32C is mounted on the bumper cover 22. Is attached. Alternatively, the fastening protrusion 22d protruding from the back surface 22a of the bumper cover 22 is inserted into the mounting hole 32C2, the fastening plug 35 is fixed to the fastening protrusion 22d protruding from the mounting hole 32C2, and the sensor housing 32C is attached to the bumper cover 22. It is attached. As a result, the holding force of the sensor unit 3C with respect to the bumper cover 22 can be increased, and the sensor unit 3C is attached to the bumper cover 22 against changes in ambient temperature, submersion of the bumper cover 22, stepping stones from the road surface, and the like. On the other hand, it can be firmly fixed.

<Configuration of Embodiment 3>
Hereinafter, a sensor unit 3D according to Embodiment 3 will be described with reference to FIGS. 10, 11A, and 11B. The sensor housing 32D (corresponding to the film support) included in the sensor unit 3D is similar to the sensor housing 32B (shown in FIG. 7B) according to the second modification of the first embodiment described above and the first housing piece 33e and the first housing piece 33e. Two housing pieces 33d are joined and formed. In addition, the piezoelectric film 31 is sandwiched between the first housing piece 33e and the second housing piece 33d in a state where they are joined to each other. (Shown in FIG. 11A). Similarly to the sensor unit 3 according to the first embodiment, the sensor unit 3D may be formed by integrally forming the piezo film 31 with respect to the sensor housing 32D.

The sensor housing 32 </ b> D covers the entire outer peripheral surface of the piezo film 31. The sensor housing 32 </ b> D extends in the vehicle width direction so as to connect both end portions of the bumper cover 22. A material similar to that of the sensor housing 32 according to the first embodiment is applied to the sensor housing 32D, which is more rigid than the piezo film 31 and has a predetermined flexibility. The sensor housing 32 </ b> D can be deformed following the shape of the bumper cover 22 when attached to the bumper cover 22. Further, the sensor housing 32 </ b> D is formed to be deformable together with the bumper cover 22 at the time of collision with the front bumper 21. Hereinafter, the first housing piece 33e and the second housing piece 33d are collectively referred to as housing pieces 33e and 33d (corresponding to a pair of support pieces).
Similar to the sensor housing 32B, the first housing piece 33e (corresponding to one of the support pieces) is a support wall 33e1 that supports one surface of the piezo film 31, and a pair of holding pieces 33e2 (holding) that face the support wall 33e1. Corresponds to the section). Accordingly, the piezoelectric film 31 is held between the holding piece 33e2 and the support wall 33e1 before the first housing piece 33e and the second housing piece 33d are joined.

A plurality of mounting bosses 33e3 project forward from the first housing piece 33e of the sensor housing 32D. As shown in FIG. 10, the plurality of mounting bosses 33e3 are formed so as to be arranged at equal intervals in the vehicle width direction. Each mounting boss 33e3 is formed in a tapered shape (shown in FIG. 11A).
As shown in FIG. 11B, each mounting boss 33 e 3 is inserted into a holding hole 22 e formed on the back surface 22 a of the bumper cover 22. Thereby, the sensor housing 32D is attached to the bumper cover 22. The holding hole 22e is formed in a shape that matches the outer peripheral surface of the mounting boss 33e3. The mounting boss 33e3 is fixed to the holding hole 22e by press fitting, welding, adhesion, or the like. The shape, size, and number of the mounting boss 33e3 and the holding hole 22e are not limited to those in the present embodiment, and can be freely set according to the space around the sensor unit 3D, the required holding force for the bumper cover 22, and the like. It is possible. Since the other configuration of the sensor unit 3D is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Effect of Embodiment 3>
According to this embodiment, the sensor unit 3D can be attached to the bumper cover 22 by inserting the attachment boss 33e3 of the sensor housing 32D into the holding hole 22e of the bumper cover 22. Thereby, there is no need for work such as screw tightening, and the work of attaching the sensor unit 3D to the bumper cover 22 can be simplified.

<Configuration of Modified Example of Embodiment 3>
Hereinafter, based on FIG. 12A, FIG. 12B, and FIG. 12C, the sensor unit 3E by the modification of Embodiment 3 is demonstrated. The sensor housing 32E (corresponding to the film support) included in the sensor unit 3E is formed by joining the first housing piece 33f and the second housing piece 33d in the same manner as the sensor housing 32D according to Embodiment 3 described above. Has been. In addition, the piezoelectric film 31 is sandwiched between the first housing piece 33f and the second housing piece 33d in a state of being joined to each other (shown in FIG. 12A). Similarly to the sensor unit 3 according to the first embodiment, the sensor unit 3E may be formed by integrally forming the piezo film 31 with respect to the sensor housing 32E. Hereinafter, the first housing piece 33f and the second housing piece 33d are collectively referred to as housing pieces 33f and 33d (corresponding to a pair of support pieces).

  Similar to the sensor housing 32D according to the third embodiment, the first housing piece 33f (corresponding to one of the support pieces) has a support wall 33f1 and a pair of holding pieces 33f2 (corresponding to the holding portion). . Similarly to the sensor housing 32D, a plurality of mounting bosses 33f3 project forward from the first housing piece 33f. Similarly to the sensor housing 32D, each mounting boss 33f3 is formed in a substantially tapered shape. On the other hand, unlike the sensor housing 32D, a retaining rib 33f4 is formed at the tip of the mounting boss 33f3. The retaining rib 33f4 protrudes outward in the radial direction on the circumference of each mounting boss 33f3.

  As shown in FIG. 12B, holding holes 22e are formed on the back surface 22a of the bumper cover 22, and hook portions 22f (corresponding to engaging portions) are formed at the bottoms of the holding holes 22e. The hook portion 22f is formed such that the inner peripheral surface of the holding hole 22e protrudes outward in the radial direction over the entire periphery. Further, an annular circumferential groove 22g having a predetermined depth in the front-rear direction is formed around the holding hole 22e so as to surround the holding hole 22e. Furthermore, between the holding hole 22e and the circumferential groove 22g, a plurality of divided slits 22h are provided on the circumference so as to connect both. Thereby, a plurality of engagement pieces 22i are formed on the circumference between the holding hole 22e and the circumferential groove 22g (shown in FIG. 12C).

  When the sensor housing 32E is attached to the bumper cover 22, the attachment boss 33f3 of the sensor housing 32E is inserted into the holding hole 22e of the bumper cover 22. Thereby, all the engagement pieces 22i are pressed radially outward by the retaining ribs 33f4. The engaging piece 22i pressed by the retaining rib 33f4 is bent toward the circumferential groove 22g, and the mounting boss 33f3 smoothly enters the holding hole 22e. When the mounting boss 33f3 further enters the holding hole 22e, the retaining rib 33f4 engages with the hook portion 22f formed in the holding hole 22e in the direction of removal from the holding hole 22e. As a result, the attachment boss 33f3 is prevented from coming off from the holding hole 22e, and the attachment of the sensor housing 32E to the bumper cover 22 is completed. Since the other configuration of the sensor unit 3E is the same as that of the sensor unit 3D according to the third embodiment, further description thereof is omitted.

<Effects of Modification of Embodiment 3>
According to this modification, in the state where the insertion of the mounting boss 33f3 into the holding hole 22e is completed, the retaining rib 33f4 of the sensor housing 32E extends from the holding hole 22e with respect to the hook portion 22f formed in the holding hole 22e. It is engaged in the direction of pulling out. Thereby, the mounting boss 33f3 can be prevented from falling off the holding hole 22e, and the holding force of the sensor housing 32E with respect to the bumper cover 22 can be increased.
Further, when the mounting boss 33f3 is inserted into the holding hole 22e, the engagement piece 22i of the bumper cover 22 is formed to be able to bend toward the circumferential groove 22g. For this reason, the mounting boss 33f3 can enter the holding hole 22e without any trouble, and the sensor unit 3E can be easily attached to the bumper cover 22.

<Configuration of Embodiment 4>
Hereinafter, based on FIG. 13A and FIG. 13B, the attachment structure to the bumper cover 22 of the piezo film 31 by Embodiment 4 is demonstrated. In the present embodiment, a clearance sonar 26 is attached to the bumper cover 22. The clearance sonar 26 is a device that detects that the bumper cover 22 and the obstacle are approaching each other, and includes a sonar housing 26a (corresponding to a film support) fixed to the bumper cover 22. The sonar housing 26a is formed of a synthetic resin material, and includes an extension portion 26a1 extending in the vehicle width direction so as to connect both ends of the bumper cover 22 and a distance measuring sensor 26b, and from the extension portion 26a1 to the front. And a plurality of protruding detection portions 26a2. The sonar housing 26a is attached to the back surface 22a of the bumper cover 22 by adhesion, fitting, or the like. Each detection unit 26 a 2 passes through a sensor hole 22 j formed in the bumper cover 22 and protrudes from the front surface 22 k of the bumper cover 22.

  The piezo film 31 according to the present embodiment is held in the sonar housing 26a by being incorporated in the extending portion 26a1 of the sonar housing 26a. The extending part 26a1 corresponds to a pair of support walls that support both sides of the piezoelectric polymer film. The piezo film 31 is integrally formed with the sonar housing 26a by insert molding or the like. The sonar housing 26 a covers the entire outer peripheral surface of the piezo film 31. The sonar housing 26a is more rigid than the piezo film 31 and has a predetermined flexibility. The sonar housing 26 a is formed so as to be deformable together with the bumper cover 22 at the time of collision with the front bumper 21. In the present embodiment, other configurations are the same as those according to the first embodiment, and thus further description thereof is omitted.

<Effect of Embodiment 4>
According to the present embodiment, the piezo film 31 is integrally formed with the extending portion 26a1 of the sonar housing 26a. Thereby, it is not necessary to provide a sensor housing other than the sonar housing 26a, and a space on the vehicle VE can be saved and the number of parts can be reduced.

<Configuration of Embodiment 5>
Hereinafter, based on FIG. 14A and FIG. 14B, the sensor unit 3F by Embodiment 5 is demonstrated. A support plate 32F (corresponding to a film support) included in the sensor unit 3F according to the present embodiment is formed in a flat plate shape, and is fitted into a support recess 22m formed on the back surface 22a of the bumper cover 22. The support plate 32F extends in the vehicle width direction so as to connect both ends of the bumper cover 22, and is fixed to the bumper cover 22 by adhesion or the like. The peripheral edge of the support plate 32 </ b> F is engaged with the locking claw 22 n of the bumper cover 22, thereby preventing the support plate 32 </ b> F from falling off the bumper cover 22. When the support plate 32F is attached to the bumper cover 22, the peripheral portion of the support plate 32F is fitted into the support recess 22m while bending the locking claw 22n of the bumper cover 22.
The support plate 32F is made of the same material as that of the sensor housing 32 according to the first embodiment, and is more rigid than the piezo film 31 and has a predetermined flexibility. Further, the support plate 32 </ b> F can be deformed following the shape of the bumper cover 22 when attached to the bumper cover 22. Further, the support plate 32 </ b> F is formed to be deformable together with the bumper cover 22 at the time of collision with the front bumper 21.

  The piezo film 31 in this embodiment is sandwiched between the back surface 22a of the bumper cover 22 and the front surface 32F1 of the support plate 32F (corresponding to the outer peripheral surface of the film support). The front surface 32F1 supports one surface of the piezo film 31 and corresponds to a support wall. The support plate 32F and the bumper cover 22 cover the entire outer peripheral surface of the piezo film 31. When the piezo film 31 is attached to the bumper cover 22, the piezo film 31 is fixed to the front surface 32 </ b> F <b> 1 of the support plate 32 </ b> F in advance by adhesion or the like, and then the support plate 32 </ b> F is attached to the bumper cover 22. The shape and size of the support plate 32F are not limited to this embodiment, and can be freely set according to the peripheral space of the sensor unit 3F, the shape of the bumper cover 22, and the like. Since the other configuration of the sensor unit 3F is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Effects of Embodiment 5>
According to this embodiment, the piezo film 31 is sandwiched between the back surface 22a of the bumper cover 22 and the support plate 32F. Thereby, since it is not necessary to make the support plate 32F into a complicated shape, the mold structure for forming the support plate 32F can be simplified.

<Configuration of Embodiment 6>
Hereinafter, based on FIG. 15A and FIG. 15B, the sensor unit 3G by Embodiment 6 is demonstrated. Similar to the sensor unit 3 according to the first embodiment, the sensor unit 3G according to the present embodiment extends in the vehicle width direction so as to connect both ends of the bumper cover 22 (in FIGS. 15A and 15B, Only the left half of the width is shown). The sensor unit 3G holds the piezo film 31 by the sensor housing 32G by covering the entire outer peripheral surface of the piezo film 31 with a sensor housing 32G (corresponding to a film support). The sensor housing 32G has a pair of support walls 32G1 and 32G2 that support both surfaces of the piezo film 31, respectively. The piezo film 31 is integrally formed with the sensor housing 32G by insert molding or the like.
The sensor housing 32 </ b> G is formed in a shape that matches the back surface 22 a of the bumper cover 22. The sensor housing 32G is made of a hard synthetic resin material so as to be fitted to the back surface 22a of the bumper cover 22, and is formed of a resin material that can be deformed together with the bumper cover 22 when it collides with the front bumper 21. . The sensor housing 32G is attached to the bumper cover 22 by bonding or fastening pins. A sensor interface 36 is connected to an end of the sensor housing 32G in the vehicle width direction. Since the other configuration of the sensor unit 3G is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Effect of Embodiment 6>
According to the present embodiment, the sensor housing 32 </ b> G is formed in a shape that matches the back surface 22 a of the bumper cover 22. Thereby, even if the back surface 22a of the bumper cover 22 has an uneven portion such as the grill portion 22p (shown in FIG. 15B), the sensor unit 3G can be mounted without deforming the sensor housing 32G according to the shape of the bumper cover 22. It can be easily attached to the bumper cover 22.

<Configuration and Effect of Modification of Embodiment 6>
Hereinafter, a modification of the sixth embodiment will be described based on FIG. 15C. The sensor housing 32 </ b> H according to this modification is attached to the bumper cover 22 so that at least a part in the vehicle width direction has a predetermined gap δ between the sensor housing 32 </ b> H and the bumper cover 22. That is, the sensor housing 32H is fixed so as to abut against the back surface 22a of the bumper cover 22 at both end portions in the vehicle width direction (only the left end portion is shown in FIG. 15C). There is a gap δ between 22p.
As a result, in the sensor unit 3H according to the present modification, by setting the gap δ between the sensor housing 32H and the bumper cover 22 to an appropriate value, the collision by the sensor unit 3H according to the position in the vehicle width direction. Sensitivity of detection can be adjusted. In FIG. 15C, a gap δ is provided between the grille portion 22p of the bumper cover 22 and the sensor housing 32H at the center in the vehicle width direction. For this reason, compared with the both ends of the vehicle width direction, the sensitivity of collision detection can be reduced in the vehicle width direction central portion where the deformation amount Q of the bumper cover 22 due to the collision is large.

Here, it is not always necessary to provide the gap δ between the bumper cover 22 and the sensor housing 32H at the center in the vehicle width direction. For example, the gap δ may be set according to the design of the bumper cover 22. That is, in the bumper cover 22, when a collision occurs at an uneven part or a part formed by a curved surface, since the deformation amount Q tends to be small, the gap δ is set to a small value (including 0) at the part. It may be set. Further, in the bumper cover 22, when a collision occurs in a wide plane part, the deformation amount Q tends to increase. Therefore, the gap δ may be set to a large value in the part.
Further, the gap δ may be set in accordance with the rigidity of the bumper cover 22. That is, in the bumper cover 22, when a collision occurs at a portion where a highly rigid structure such as a headlamp is present inside, the deformation amount Q tends to be small, and therefore the gap δ is set to a small value (0 May be included).

<Configuration of Embodiment 7>
Hereinafter, based on FIG. 16 thru | or FIG. 18B, the sensor unit 3J by Embodiment 7 is demonstrated. The sensor unit 3J according to the present embodiment is formed by integrally forming a piezo film 31 with respect to a sensor housing 32J (corresponding to a film support) in the same manner as the sensor unit 3 according to the first embodiment (see FIG. 17A). ). The entire outer peripheral surface of the piezo film 31 is covered with a sensor housing 32J. However, the sensor unit 3J according to the present embodiment is not necessarily limited to this, and the sensor housing 32J is formed of a pair of housing pieces that are fitted to each other as in the first modification of the first embodiment. Also good. The sensor housing 32J extends in the vehicle width direction so as to connect both ends of the bumper cover 22 (shown in FIG. 16). The sensor housing 32J has a pair of support walls 32J1 and 32J2 that support both surfaces of the piezo film 31, respectively.

  In the sensor unit 3J, the thickness of the sensor housing 32J differs depending on the position in the vehicle width direction. Accordingly, the rigidity of the sensor housing 32J varies depending on the position in the vehicle width direction. In the center CR in the vehicle width direction shown in FIG. 16 (hereinafter simply referred to as the center CR), the sensor housing 32J has a thickness D (shown in FIG. 17A). On the other hand, at the corner portion RH at the right end portion in the vehicle width direction and the corner portion LH at the left end portion in the vehicle width direction, the thickness of the sensor housing 32J is formed to be d smaller than D (shown in FIG. 17B). Hereinafter, the corner portion RH and the corner portion LH are collectively referred to as the corner portions RH and LH. Although not limited to this, the thickness D of the center CR is set to, for example, twice the thickness d of the corner portions RH and LH. As a result, the sensor housing 32J according to the present embodiment is formed such that the rigidity of the center CR is larger than the rigidity of the corner portions RH and LH, and the rigidity of the center CR is approximately twice the rigidity of the corner portions RH and LH. Is set to

The pedestrian protection system 1 activates the pedestrian protection device 5 when a pedestrian collides with the vehicle VE, and operates the pedestrian protection device 5 when a small animal collides. Absent. However, as shown in FIG. 18B, when the vehicle VE collides, the center CR has a larger deformation amount of the bumper cover 22 due to the collision than the corner portions RH and LH, and the piezo film voltage Vpz generated by the sensor unit 3J. Tend to be higher. Therefore, it is very difficult to set a certain threshold value Vthc that can distinguish between a collision caused by a pedestrian and a collision caused by a small animal or the like.
On the other hand, there is a method of setting a map-type threshold value Vthv (shown in FIG. 18B) having different values depending on the collision position in the vehicle width direction. However, in this case, there is a problem that the pedestrian protection ECU 6 needs to detect the collision position in the vehicle width direction, and a complicated algorithm for collision detection or the like is required.

  As described above, the sensor housing 32J according to the present embodiment is formed such that the rigidity of the center CR is larger than that of the corner portions RH and LH. For this reason, as shown in FIG. 18A, when the vehicle VE collides, the center CR and the corner portions RH and LH have the same displacement amount due to the collision, and the piezo film voltage Vpz generated by the sensor unit 3J. The difference between the two has been reduced. Therefore, it is possible to distinguish between a collision caused by a pedestrian and a collision caused by a small animal or the like based on a certain threshold value Vthc.

The sensor housing 32J is not limited only to the center CR having a larger rigidity than the corners RH and LH. For example, the rigidity of the sensor housing 32J may be set in accordance with the design of the bumper cover 22. That is, in the bumper cover 22, when a collision occurs at an uneven portion or a portion formed by a curved surface, the deformation amount of the bumper cover 22 tends to be small, so the rigidity of the sensor housing 32 </ b> J is set to a small value. Also good. Further, in the bumper cover 22, when a collision occurs in a wide plane portion, the deformation amount is likely to increase, and therefore the rigidity of the sensor housing 32J may be set to a large value. Also, in the bumper cover 22, when a collision occurs at a portion where a highly rigid structure such as a headlamp is present inside, the deformation amount is likely to be small. Therefore, the rigidity of the sensor housing 32J is set to a small value. Also good.
The sensor housing 32J of the sensor unit 3J may be formed of a foam material such as slab urethane or molded urethane. In this case, the foam density of the center CR can be made larger than the foam density of the corner portions RH and LH, and the rigidity of the center CR can be made larger than the stiffness of the corner portions RH and LH. Further, in the sensor housing 32J formed of a foam material, the thickness of the center CR may be larger than the thickness of the corner portions RH and LH.
Since the other configuration of the sensor unit 3J is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<Effects of Embodiment 7>
According to the present embodiment, since the sensor housing 32J has different rigidity according to the position in the vehicle width direction, the amount of displacement due to the collision is substantially the same regardless of the position in the vehicle width direction where the collision has occurred. can do. For this reason, it is possible to accurately detect a collision by a pedestrian based on a certain threshold value Vthc.
In addition, it is possible to accurately detect a collision by a pedestrian based on a certain threshold value Vthc regardless of the position in the vehicle width direction where the collision has occurred. The algorithm can be simplified.
Further, since the sensor housing 32J has a different thickness depending on the position in the vehicle width direction, the rigidity of the sensor housing 32J can be varied depending on the position in the vehicle width direction with a simple configuration. Furthermore, the sensor housing 32J can easily vary the rigidity of each position by only changing its mold.

<Configuration of First Modification of Embodiment 7>
Hereinafter, based on FIG. 19A and FIG. 19B, the sensor unit 3K by the 1st modification of Embodiment 7 is demonstrated. Similar to the sensor unit 3 according to the first embodiment, the sensor unit 3K according to the present embodiment is formed by integrally forming a piezo film 31 with respect to a sensor housing 32K (corresponding to a film support). The entire outer peripheral surface of the piezo film 31 is covered with a sensor housing 32K. The sensor housing 32K has a pair of support walls 32K1 and 32K2 that support both surfaces of the piezo film 31, respectively. The sensor housing 32K extends in the vehicle width direction so as to connect both end portions of the bumper cover 22.

As shown in FIG. 19A, the sensor housing 32K has a plurality of ribs 32K3 on the support wall 32K2 (corresponding to at least part of the outer peripheral surface) in the center CR. On the other hand, the sensor housing 32K does not have the rib 32K3 at the corner portions RH and LH (shown in FIG. 19B). Thereby, the sensor housing 32K is formed such that the rigidity of the center CR is larger than that of the corner portions RH and LH.
The sensor housing 32K may include ribs 32K3 on both the center CR and the corner portions RH and LH, and the number of ribs 32K3 on the center CR may be larger than the number of ribs 32K3 on the corner portions RH and LH.
Further, the sensor housing 32K may be provided with ribs 32K3 on both the center CR and the corner portions RH and LH, and the rib 32K3 of the center CR may be formed larger than the ribs 32K3 of the corner portions RH and LH.
The sensor housing 32K is provided with ribs 32K3 on both the center CR and the corner portions RH and LH, and the shape of the rib 32K3 of the center CR is larger than the shape of the ribs 32K3 of the corner portions RH and LH. Also good.
Further, the rib 32K3 according to the present embodiment may be combined with that according to the seventh embodiment described above. That is, the thickness of the center CR may be larger than the thickness of the corner portions RH and LH, and the rib 32K3 may be formed only in the center CR.
Since the other configuration of the sensor unit 3K is the same as that of the sensor unit 3 according to the first embodiment, further description thereof is omitted.

<The effect of the 1st modification of Embodiment 7>
According to the present embodiment, the plurality of ribs 32K3 are formed only in the center CR of the sensor housing 32K. Thereby, the rigidity of the center CR can be formed larger than the corner portions RH and LH of the sensor housing 32K with a simple configuration. Further, the rigidity of each position of the sensor housing 32K can be easily changed by changing the mold.

<Configuration of Second Modification of Embodiment 7>
Hereinafter, based on FIG. 20A thru | or FIG. 20C, the sensor unit (no code | symbol) by the 2nd modification of Embodiment 7 is demonstrated. Similar to the sensor unit 3 according to the first embodiment, the sensor unit according to the present embodiment is formed by covering the entire outer peripheral surface of the piezo film 31 with a sensor housing 32L (corresponding to a film support). The sensor housing 32L extends in the vehicle width direction so as to connect both end portions of the bumper cover 22. The sensor housing 32L according to the present embodiment is formed of a fiber cloth. The fiber cloth used for the sensor housing 32K is not limited to these, but, for example, woven cloth or felt such as nylon or polyamide, or other non-woven cloth is applicable.

Similarly to the sensor housing 32J according to the seventh embodiment, the sensor housing 32L is formed such that the thickness of the center CR is larger than the thickness of the corner portions RH and LH, and the rigidity of the center CR is set larger than the rigidity of the corner portions RH and LH. May be.
Further, if the sensor housing 32L is formed of a woven fabric, the thickness (denier) of the fibers used for the sensor housing 32L may be varied according to the position in the vehicle width direction. For example, a fiber thicker than the corner portions RH and LH is used for the center CR. Thereby, the rigidity of the center CR is formed larger than the rigidity of the corner portions RH and LH.
Further, if the sensor housing 32L is formed of a woven fabric, the pattern of the weave may be varied depending on the position in the vehicle width direction. For example, as shown in FIG. 20A, a pattern of weaving the corner portions RH and LH is a pattern 32L1 (first pattern) woven vertically and horizontally. Then, as shown in FIG. 20B, the pattern of the center CR weaving pattern is a pattern 32L2 (second pattern) similarly woven vertically and horizontally, and pattern 2 is denser than pattern 1, The rigidity may be larger than the rigidity of the corner portions RH and LH.
Furthermore, as shown in FIG. 20C, by using a weaving pattern 32L3 (third pattern) woven in an oblique direction in a part of the sensor housing 32L, the sensor can be adjusted in accordance with the position in the vehicle width direction. The rigidity of the housing 32L may be varied.

<The effect of the 2nd modification of Embodiment 7>
According to the present embodiment, the sensor housing 32L includes a fiber cloth, and the thickness of the fibers used in the fiber cloth or the pattern of the weave differs depending on the position in the vehicle width direction. Thereby, the rigidity of each position of the sensor housing 32L can be easily changed with a simple configuration.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
As long as those skilled in the art can implement the above-described first to seventh embodiments and their respective modifications using technical techniques, they may be combined in any manner.
Further, a plurality of sensor units 3 may be mounted on the bumper cover 22 so as to be aligned in the vehicle width direction or the vertical direction.
Further, the entire outer peripheral surface of the piezo film 31 is not necessarily covered by the sensor housing 32. If supported by the sensor housing 32, a part of the outer peripheral surface of the piezo film 31 may be exposed from the sensor housing 32.
In the sensor unit 3J according to the seventh embodiment, the rigidity of each position may be changed by changing the material of the sensor housing 32J according to the position in the vehicle width direction.

  In the drawings, 1 is a pedestrian protection system (vehicle collision detection device), 5 is a pedestrian protection device (protection device), 21 is a front bumper (front part of the vehicle), 22 is a bumper cover, 22a is a back surface (bumper cover). Inner surface), 22d is a fastening protrusion, 22e is a holding hole, 22f is a hook part (engagement part), 26a is a sonar housing (film support), 26a1 is an extension part (support wall), and 26b is a distance measuring sensor. , 31 is a piezo film, (piezoelectric polymer film), 32, 32A, 32B, 32C, 32D, 32E, 32G, 32H, 32J, 32K, 32L are sensor housings (film supports), 32a, 32b, 32C3 32C4, 32G1, 32G2, 32J1, 32J2, 32K1, 32K2, 33a1, 33b1, 33c1, 33d1, 33e1, 33f1 Support wall, 32K3 is a rib, 32L1, 32L2, and 32L3 are weaving patterns, 32C2 is a mounting hole, 32F is a support plate (film support), and 32F1 is a front surface of the support plate (outer peripheral surface of the film support, support wall) 33a, 33c, 33e and 33f are first housing pieces (support pieces), 33b and 33d are second housing pieces (support pieces), 33c2, 33e2 and 33f2 are holding pieces (holding portions), and 33e3 and 33f3 are mounting bosses. , 33f4 is a retaining rib, 34 is a fastening pin (fastening member), 35 is a fastening plug, 62 is a collision determination unit, Q is a deformation amount of the bumper cover, VE is a vehicle, Vpz is a piezo film voltage (output voltage), and δ is A predetermined gap is shown.

Claims (17)

A piezoelectric polymer film (31) that generates a predetermined output voltage (Vpz) by being deformed; and
Support walls (32a, 32b, 32C3, 32C4, 32G1, 32G2, 32J1, 32J2, 32K1, 32K2, 33a1, support walls that are more rigid than the piezoelectric polymer film and support at least one surface of the piezoelectric polymer film. 33b1, 33c1, 33d1, 33e1, 33f1, 26a1, 32F1) and attached to the inner side surface (22a) of the bumper cover (22) provided at the front portion (21) of the vehicle (VE). A film support (32, 32A, 32B, 32C, 32D, 32E, 32F, 32G, 32H, 32J, 32K, 32L, 26a) that can be deformed together with the cover;
Depending on the deformation amount (Q) of the bumper cover, the bumper cover needs to be activated by a protective device (5) for protecting the collision object based on the output voltage generated by the piezoelectric polymer film. A collision determination unit (62) for detecting that a collision has occurred;
A vehicle collision detection device (1).   The film support (32, 32A, 32B, 32C, 32D, 32E, 32G, 32H, 32J, 32K, 26a) is a pair of support walls (32a, 32b, The vehicle collision detection device according to claim 1, further comprising: 32C3, 32C4, 32G1, 32G2, 32J1, 32J2, 32K1, 32K2, 33a1, 33b1, 33c1, 33d1, 33e1, 33f1, 26a1).   3. The vehicle collision detection device according to claim 1, wherein the piezoelectric polymer film is integrally formed with the film support (32, 32 C, 32 G, 32 H, 32 J, 32 K, 26 a). The film support is
Formed from a pair of support pieces (33a, 33b, 33c, 33d, 33e, 33f) joined together,
The piezoelectric polymer film is
The vehicle collision detection device according to claim 1, wherein the vehicle collision detection device is interposed between the support pieces. One of the support pieces (33c, 33e, 33f)
The holding part (33c2, 33e2, 33f2) formed so as to oppose the support wall (33c1, 33e1, 33f1) and sandwiching the piezoelectric polymer film together with the support wall. Vehicle collision detection device.   A mounting hole (32C2) passes through the film support (32C), and is formed in the fastening member (34) that passes through the mounting hole and is fixed to the bumper cover, or the bumper cover. In addition, the film support is attached to the bumper cover by a fastening protrusion (22d) inserted into the attachment hole, and a portion protruding from the attachment hole is fixed to the fastening plug (35). The vehicle collision detection device according to any one of claims 1 to 5.   Mounting bosses (33e3, 33f3) protrude from the film support (32D, 32E), and the mounting bosses are inserted into holding holes (22e) formed in the bumper cover, thereby The vehicle collision detection device according to any one of claims 1 to 5, wherein the film support is attached to the bumper cover.   The mounting boss (33f3) is formed with a retaining rib (33f4) protruding in the radial direction. In the state where the mounting boss is inserted into the holding hole, the retaining rib is formed in the holding hole. The vehicle collision detection device according to claim 7, wherein the engagement portion (22f) is engaged with the engagement portion (22f) in a direction in which the engagement portion (22f) is removed from the holding hole. The film support is
A sonar housing (26a) containing a distance measuring sensor (26b),
4. The vehicle collision detection device according to claim 1, wherein the piezoelectric polymer film is integrally formed with the sonar housing. 5. The piezoelectric polymer film is
The vehicle collision detection device according to claim 1, wherein the vehicle collision detection device is sandwiched between an outer peripheral surface of the film support (32F) and the bumper cover.   The collision detection device for a vehicle according to any one of claims 1 to 5, wherein the film support (32G, 32H) is formed in a shape that matches the inner surface of the bumper cover.   The film support (32H) is attached to the bumper cover so that at least a part of the film support (32H) has a predetermined gap (δ) between the film support (32H) and the bumper cover. The vehicle collision detection device according to any one of the above. The film support (32J, 32K, 32L)
The vehicle collision detection device according to any one of claims 1 to 12, wherein the rigidity differs according to a position in a vehicle width direction. The film support is
The vehicle collision detection device according to claim 13, wherein the thickness differs according to the position in the vehicle width direction. The film support (32K)
A rib (32K3) is provided on at least a part of the outer peripheral surface, and the presence or absence of the rib, the number of the ribs, the size of the rib, or the shape of the rib varies depending on the position in the vehicle width direction. The vehicle collision detection device according to claim 13 or 14. The film support (32L)
A fiber cloth is included, and the thickness of the fiber used in the fiber cloth or the pattern of the weave of the fiber cloth (32L1, 32L2, 32L3) differs depending on the position in the vehicle width direction. The vehicle collision detection device according to 13 or 14. The film support (32J)
The vehicle collision detection device according to claim 13 or 14, wherein the vehicle collision detection device is formed of a foam material and has a foam density different depending on a position in a vehicle width direction.

Images