JP2015105085A - Pedestrian collision detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pedestrian collision detection device which has an improved sensitivity while protecting a pedestrian.SOLUTION: In a pedestrian collision detection device according to the present invention, a first foam material 16 is fixedly disposed on a top surface upper part of a bumper support member 14, and a second foam material 20, which is independent from the first foam material 16, is disposed on a front surface lower part of the bumper support member 14. Further, a detection tube 24, which functions as a sensor for detecting a pedestrian, is located between the second foam material 20 and the bumper support member 14. Consequently, it is possible to specialize a shape and a blank of the second foam material 20 for the purpose of detecting a pedestrian, and to improve an accuracy of detection of a pedestrian at the time of collision.

Description

  The present invention relates to a pedestrian collision detection device for inflating and deploying an airbag on a hood when a pedestrian collides with a traveling vehicle.

  It is known that a secondary collision occurs when a traffic accident occurs between a pedestrian and a vehicle. This secondary collision means that when a vehicle traveling at a predetermined speed or more collides with a pedestrian, the pedestrian collides with a vehicle bumper, and then is lifted onto the front hood and collides with a windshield or the like. is there.

  In order to protect a pedestrian from this secondary collision, Patent Document 1 discloses a pedestrian protection device that inflates and deploys an airbag on a front hood. Referring to FIG. 1 of Patent Document 1, an airbag module 10 provided in the pedestrian protection device is installed on a front hood 4 of a vehicle. The airbag module 10 is configured to inflate and deploy the airbag 15 on the front hood 4.

  Further, the following Patent Document 2 to Patent Document 4 describe matters in which a collision is detected by a sensor arranged in front of the vehicle and the airbag on the hood is activated according to the detected result.

  In Patent Literature 2, an absorber 20 and a chamber member 18 are disposed on the front surface of the bumper reinforcement 14 with reference to FIG. The chamber member 18 is attached to the front upper portion of the front surface of the bumper reinforcement 14. In this state, when the vehicle collides with a pedestrian, the pressure change of the chamber member 18 to which the impact has been applied is detected by the pressure sensor 22, and the airbag is activated.

  In Patent Document 3, with reference to FIG. 2 and the explanation thereof, a chamber member 71 is disposed on the upper front surface of the bumper reinforcement 4, and an absorber 6 is disposed on the lower front surface thereof. When a collision is applied to the vehicle, the chamber member 71 is deformed, and the pressure change in the chamber member 71 is detected by the pressure sensor 72. Further, the airbag or the like is operated in accordance with the output of the pressure sensor 72.

  In Patent Document 4, referring to FIG. 2 and the explanation thereof, the displacement sensor 2 is arranged on the front surface of the reinforcement 3. Then, when the displacement sensor 2 generates a signal indicating detection of a pedestrian when the vehicle collides, control is performed to raise the hood.

Japanese Patent No. 2920284 JP 2011-245910 A JP 2010-100075 A Japanese Patent Laid-Open No. 11-28994

  However, in the detection devices described in Patent Document 2 to Patent Document 4 described above, pedestrians may not be properly protected.

  Specifically, with the pedestrian detection device described in Patent Document 2, with reference to FIG. 2, the chamber member 18 that functions as a sensor includes an absorber 20 that absorbs an impact, a bumper reinforcement 20, It is arranged between. Therefore, by arranging the absorber 20 for detection, the effective area of the absorber 20 that functions as an impact reducing material is reduced, and there is a possibility that the action of reducing the impact by the absorber 20 may be reduced.

  In the vehicle collision detection device described in Patent Document 3, with reference to FIG. 2 and the like, a detection chamber 71 is disposed at the upper front surface of the bumper reinforcement 4, and the absorber 6 is disposed only at the lower front surface. Has been placed. Therefore, there is a possibility that the effect of absorbing shock may be reduced by reducing the cross-sectional area of the absorber 6.

  In the protection sensor system described in the cited document 4, referring to FIG. 2 and the explanation thereof, the displacement sensor 2 is arranged on the front surface of the reinforcement 3, and the displacement sensor 2 and the front bumper 1 are There is no shock absorber in between. Therefore, there is a problem that it is difficult to protect pedestrians and the like from accidents because they have little action of absorbing impacts at the time of collision. Moreover, since the front bumper 1 directly contacts the displacement sensor 2 at the time of an impact action, it may be difficult to determine whether or not the target with which the vehicle collides is a pedestrian.

  This invention is made | formed in view of an above-described subject, and the objective of this invention is providing the pedestrian collision detection apparatus which improved the sensitivity, protecting a pedestrian.

  The pedestrian collision detection device according to the present invention includes a foam material disposed between a bumper support member and a bumper skin, and an impact that is disposed between the bumper support member and the foam material and acts on the bumper skin. A sensor part for measuring the size of the air bag, and an airbag that inflates and deploys based on the output of the sensor part, wherein the foam material is attached to the front surface of the bumper support member and acts on the bumper skin A first foam material that absorbs water and a second foam material attached to the front surface of the bumper support member as a separate body from the first foam material, and the sensor unit includes the second foam material It is arrange | positioned between the said bumper support parts, It is characterized by the above-mentioned.

  According to the present invention, the first foam material for shock absorption is disposed on the front surface of the bumper support member, and the second foam material is disposed on the front surface separately from the first foam material. Is disposed between the second foam material and the bumper support portion. Thereby, a pedestrian is protected because the impact at the time of a collision is absorbed favorably by the 1st foam material. Furthermore, since the second foam material disposed in front of the sensor unit is separate from the first foam material, the hardness of the second foam material can be appropriately selected in order to operate the sensor unit appropriately. It becomes possible.

It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is a perspective view which shows the vehicle with which a pedestrian collision detection apparatus is equipped, (B) is a perspective view which shows a pedestrian collision detection apparatus. It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is a perspective view which shows the vehicle with which an impact-absorbing member is equipped, (B) is sectional drawing in the BB 'line of (A). is there. It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is sectional drawing which shows the condition where each foam material is crushed at the time of a collision, (B) is a block diagram which shows the structure of a pedestrian collision detection apparatus. (C) is a graph showing the relationship between time and sensor output.

  Hereinafter, the pedestrian collision detection device of the present embodiment will be described with reference to the drawings. In the following description, UP indicates the upward direction, DOWN indicates the downward direction, LH indicates the left direction when facing the traveling direction of the vehicle, RH indicates the right direction in the same case, and FR indicates the forward direction. RE indicates backward.

  With reference to FIG. 1A, the pedestrian collision detection device of the present embodiment is provided on the back side of the bumper skin 18 disposed at the front end portion of the vehicle 10. And if a pedestrian detection apparatus detects that the vehicle 10 collided with the pedestrian, the airbag arrange | positioned in the vicinity of the front bumper 12 will inflate and deploy, and will protect a pedestrian from a secondary collision.

  With reference to FIG. 1 (B), the pedestrian collision detection apparatus 22 of this form is equipped with the bumper support member 14 attached to the vehicle body side from the RE side, and the detection tube 24 arrange | positioned at the front lower part of the bumper support member 14. And a first foam material 16 disposed on the front upper portion of the bumper support member 14 and a second foam material 20 disposed between the detection tube 24 and the bumper skin 18. The airbag is operated based on the output of the pressure sensor that detects the atmospheric pressure. Further, these members are arranged at the same height as the bumper skin 18.

  The bumper support member 14 is a metal member extending in the width direction of the vehicle, and has a role of supporting the first foam material 16 and the like and absorbing energy at the time of a large collision. When the vehicle 10 is impacted when traveling at a low speed, the bumper support member 14 is not deformed in principle.

  The detection tube 24 is a pipe-shaped resin member having a circular cross section, and the inside is sealed. The detection tube 24 is continuously arranged from the vicinity of the RH side end of the bumper support member 14 to the vicinity of the LH side end. A pressure sensor (not shown) is arranged inside the detection tube 24, and a pedestrian's collision is detected by detecting the pressure fluctuation when the detection tube 24 is compressed by an impact at the time of collision. doing.

  The first foam material 16 is made of a resin material, and is continuously arranged from the vicinity of the LH side end of the bumper support member 14 to the vicinity of the RH side end. As the material of the first foam material 16, a foamed resin made of PP foam material or polyethylene is adopted. Since the first foam material 16 has an action of absorbing an impact generated at the time of collision, the first foam material 16 is harder than the second foam material 20. Specifically, the expansion ratio of the first foam material 16 is set smaller than the expansion ratio of the second foam material 20. For example, if the expansion ratio of the second foam material 20 is about 30 times, the expansion ratio of the first foam material 16 is less than half (for example, about 15 times). For the same reason, the cross-sectional area of the first foam material 16 is formed larger than that of the second foam material 20. Further details of the first foam material 16 will be described later with reference to FIG.

  Similar to the first foam material 16, the second foam material 20 is made of a foamed resin continuously formed from the vicinity of the end portion on the LH side of the bumper support member 14 to the vicinity of the end portion on the RH side. Further, the second foam material 20 is disposed between the detection tube 24 and the bumper skin 18. The main role of the second foam material 20 is to appropriately transmit the collision energy generated by the collision to the detection tube 24. Further details of the first foam material 16 will be described later with reference to FIG.

  With reference to FIG. 2, the configuration of the above-described pedestrian collision detection apparatus of the present invention will be further described. 2A is a perspective view showing the vehicle 10, and FIG. 2B is a cross-sectional view taken along the line B-B 'of FIG. 2A.

  2A and 2B, a first foam material 16 and a second foam material 20 are disposed between the bumper skin 18 and the bumper support member 14 disposed at the front end portion of the vehicle 10. And the detection tube 24 is arrange | positioned. Thereby, when the vehicle 10 collides with a pedestrian, the impact which acts on the leg part 28 of a pedestrian is relieved because the 1st foam material 16 compresses and deforms. Furthermore, the second foam material 20 is compressed and deformed, so that collision energy is transmitted to the detection tube 24 and the detection accuracy is improved.

  Referring to FIG. 2A, the first foam material 16 has a cross-sectional shape obtained by rotating the shape of the katakana “ko” by 180 degrees, and the end on the FR side is closest to the inner surface of the bumper skin 18. Is arranged. Thereby, immediately after the leg part 28 contacts the bumper skin 18 at the time of the collision, the first foam material 16 is pressed toward the RE side from the inner surface of the bumper skin 18 and is compressed and deformed, so that the effect of protecting the leg part 28 is great. Become.

  Similarly, in the second foam material 20, the end on the FR side is disposed in the immediate vicinity of the inner surface of the bumper skin 18. The FR side end of the second foam material 20 may contact the inner surface of the bumper skin 18 or a slight gap may exist between them. Thereby, immediately after the bumper skin 18 collides with the leg portion 28, the second foam material 20 starts to be deformed, and at the same time, the compression deformation of the detection tube 24 also begins to increase the internal pressure. Therefore, since the time during which a collision can be detected by the detection tube 24 becomes longer, the accuracy of the determination of a pedestrian collision can be increased using the speed parameter obtained by this detection.

  The detection tube 24 is disposed between the second foam material 20 and the bumper support member 14 in a state where it can be deformed by a compressive force due to a collision. Here, it is built in the second foam material 20 in the vicinity of the bumper support member 14. Theoretically, it is possible to detect a collision with a pedestrian using only the detection tube 24 arranged in front of the bumper support member 14. However, if it does in this way, since the internal pressure of the detection tube 24 will fluctuate rapidly with a collision, it will not be easy to determine whether or not the colliding target is a pedestrian. In this embodiment, the second foam material 20 is arranged between the detection tube 24 and the bumper skin 18 to improve the accuracy of detecting a collision with a pedestrian, and the airbag is activated at an unnecessary timing. So-called false explosions are prevented.

  In this embodiment, the first foam material 16 and the second foam material 20 are not formed from the same foamed resin material, but are separated from each other. Specifically, the first foam material 16 has a role of absorbing impact when colliding with a pedestrian, while the second foam material 20 has a role of transmitting impact energy at the time of collision to the detection tube 24. Therefore, by using the first foam material 16 and the second foam material 20 as separate members, it is possible to select an optimal shape, position, material, etc. according to each role. In addition, the first foam material 16 can be used in common for a plurality of vehicle types regardless of the presence or absence of the pedestrian detection mechanism, so that development efficiency is also improved.

  Furthermore, in this embodiment, on the front surface of the bumper support member 14, the first foam material 16 is provided at the upper portion, and the second foam material 20 is disposed at the lower portion. When the vehicle 10 collides with a pedestrian, compression stress mainly acts on the upper part of the bumper support member 14. Therefore, by arranging the first foam material 16 on the upper part, this compressive stress can be well absorbed by the first foam material 16 whose material and the like are optimized for absorbing the impact, so that the pedestrian legs 28 are provided. The effect of protecting is increased. Further, since the detection tube 24 is not disposed on the first foam material 16, the remaining crushing is reduced, and this also secures the effect of absorbing shock.

  Furthermore, when the vehicle 10 collides with a pedestrian, the leg portion 28 rotates, so that the foam material disposed in front of the lower portion of the bumper support member 14 has a small effect of absorbing the impact. Therefore, even if the 2nd foam material 20 for a pedestrian detection is arrange | positioned in this lower part front, the fall of the impact absorption as the whole apparatus is small.

  In the present embodiment, the second foam material 20 is made of a softer material than the first foam material 16. Specifically, as described above, the second foam material 20 is made of a resin material having a higher expansion ratio than the first foam material 16. Further, the second foam material 20 has a hardness that can be deformed by a load that can be detected by the detection tube 24. Thereby, when the second foam material 20 is pressed to the RE side by the bumper skin 18 when a collision impact is applied, the second foam material 20 and the detection tube 24 are simultaneously deformed. Therefore, the impact acting by the collision is detected well.

  With reference to FIG. 3, an operation when the vehicle 10 collides with a pedestrian will be described. 3A is a cross-sectional view showing the vehicle 10 at the time of a collision, FIG. 3B is a block diagram showing a connection configuration of the pedestrian collision detection device 22, and FIG. 3C is a sensor output value. It is a graph which shows a time-dependent change.

  Referring to FIG. 3A, when vehicle 10 collides with a pedestrian, pedestrian's legs 28 collide with bumper skin 18 and grill 26, and the pedestrian's torso temporarily rises above grill 26. You can jump up. As a result, the bumper skin 18 and the grill 26 of the vehicle 10 are deformed to the RE side. The lower end of the grill 26 and the upper end of the bumper skin 18 are supported by a plate-like support plate 38 provided at the upper end of the bumper support member 14. As a result, the intrusion of the grill 26 and the bumper skin 18 into the vehicle 10 is suppressed.

  With the deformation of the bumper skin 18 toward the RE side, the first foam material 16 is compressed and deformed by the compressive force generated by the collision. Since the pedestrian's leg portion 28 is rotated clockwise by the collision, most of the impact energy generated by the collision is absorbed by the first foam material 16, and the effect of protecting the pedestrian's leg portion 28 is increased. .

  Simultaneously with the deformation of the first foam material 16, the second foam material 20 disposed below the first foam material 16 also undergoes compression deformation due to the collision. As described above, the second foam material 20 is made of a softer material than the first foam material 16, and the hardness thereof is approximately the same as that of the detection tube 24. Further, the FR-side end portion of the second foam material 20 is substantially in contact with the inner surface of the bumper skin 18. Therefore, the second foam material 20 gradually compresses and deforms immediately after the collision. Simultaneously with this deformation, the detection tube 24 is also compressed and deformed, and the internal pressure rises.

  Referring to FIG. 3B, the pressure inside detection tube 24 is measured by pressure sensor 34, and information indicating this pressure is output to ECU 30 (Electronic Control Unit). In addition, information indicating the speed of the vehicle 10 is input to the ECU 30 from the speed sensor 36. This is because the pedestrian airbag is deployed only when the vehicle speed is constant.

  The ECU 30 determines whether or not the vehicle 10 has collided with a pedestrian based on information obtained from these sensors. When it is determined that the vehicle 10 has collided with a pedestrian, the airbag 32 is inflated and deployed on the upper surface of the front hood based on the output of the ECU 30 to protect the pedestrian.

  With reference to the graph shown in FIG. 3C, the above-described determination is performed using the compression speed as a parameter by the configuration of the second foam material 20 of the present embodiment described above, and the airbag 32 is deployed based on the erroneous determination. Can be prevented. In this graph, the horizontal axis represents the elapsed time since the collision, and the vertical axis represents the output value (pressure change value) of the pressure sensor 34.

  Referring to this graph, in the region indicated by T1, the change over time of the sensor output schematically shows a primary waveform. This is realized by the second foam material 20 and the detection tube 24 shown in FIG. 3 having the same hardness and being deformed at the same time. Since the temporal change of the sensor output shows a primary waveform, it is possible to easily determine a pedestrian collision based on the time information (speed information). If a foamed resin material that is harder than the detection tube 24 is adopted as the material of the second foam material 20, this waveform rapidly changes at an early stage, making it difficult to make a judgment based on time. In addition, when a foamed resin material that is extremely softer than the detection tube 24 is used as the material of the second foam material 20, the waveform similarly suddenly fluctuates, so the above determination is not easy.

  In this embodiment, by adopting the above-described configuration, the pressure sensor 34 allows the inside of the detection tube 24 for a long time until the second foam material 20 is compressed after the vehicle 10 collides with a pedestrian. It becomes possible to measure the pressure change in this. Therefore, the time required to compress the second foam material 20 and the applied pressure can be accurately measured.

  Specifically, in this embodiment, it is determined that the vehicle 10 has collided with a pedestrian and the airbag is deployed only when the time T1 from when the pressure starts to reach a certain sensor output value is within a certain range. doing.

  When this time T1 is less than a certain time, it is a result of the second foam material 20 being rapidly compressed. For example, it is presumed that the vehicles have collided with each other, so the airbag is not deployed. Further, when the time T1 is longer than the predetermined time, for example, it is estimated that an object other than a human body such as a ball has contacted the bumper portion of the vehicle 10, so that the airbag is not deployed in this case as well. Such a configuration prevents accidental explosion of the airbag.

  The above is the description regarding the pedestrian collision detection device 22 of the present embodiment.

DESCRIPTION OF SYMBOLS 10 Vehicle 12 Front bumper 14 Bumper support member 16 1st foam material 18 Bumper skin 20 2nd foam material 22 Pedestrian collision detection apparatus 24 Detection tube 26 Grill 28 Leg 30 ECU
32 Airbag 34 Pressure sensor 36 Speed sensor 38 Support plate

Claims (5)

A foam material disposed between the bumper support member and the bumper skin;
A sensor unit that is disposed between the bumper support member and the foam material and measures the magnitude of an impact acting on the bumper skin,
An airbag that inflates and deploys based on the output of the sensor unit,
The foam material is attached to the front surface of the bumper support member as a separate body from the first foam material that is attached to the front surface of the bumper support member and absorbs an impact applied to the bumper skin. A second foam material,
The pedestrian collision detection device, wherein the sensor unit is disposed between the second foam material and the bumper support unit.   The pedestrian collision detection device according to claim 1, wherein the second foam material is disposed below the first foam material.   The pedestrian collision detection device according to claim 1 or 2, wherein the second foam material is softer than the first foam material.   The pedestrian collision detection device according to any one of claims 1 to 3, wherein a front tip portion of the second foam material is brought close to the bumper skin. The pedestrian collision detection device according to any one of claims 1 to 4, wherein the sensor unit is a detection tube disposed on a front surface of the bumper support member and deformed by the impact.

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