JP2016055710A - Pedestrian collision detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pedestrian collision detection device with higher accuracy of collision detection.SOLUTION: A pedestrian collision detection device 11 includes a bumper support member 18 extending in a vehicle width direction, a foam material 20 arranged in front of the bumper support member 18; and a detection tube 22 which is arranged on the foam material 20 and deforms by an impact acting on a vehicle. The foam material 20 includes a front surface member 20A facing a collision direction, an upper member 20B extending from an upper part of the front surface member 20A to a rear side, and a lower member 29C extending from a lower part of the front surface member 20A to the rear side. At least either of the upper member 20B or the lower member 20C has an inclined shape in which a rear part separates from a horizontal line than a front part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pedestrian collision detection device, and more particularly to a pedestrian collision detection device incorporating a sensor unit that detects a collision with a pedestrian by a pressure change.

  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.

  Patent Document 1 discloses a pedestrian protection device that inflates and deploys an airbag on a front hood in order to protect a pedestrian from a secondary collision. 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.

  Moreover, the matter which makes a sensor operate | move suitably by devising the shape of an impact-absorbing member is described in the following patent documents 2.

  In Patent Document 2, referring to FIG. 5 and the explanation thereof, a collision detection sensor that simplifies the assembly work is disclosed. Specifically, the collision detection sensor 1 includes a load detection unit 2 that detects a load at the time of collision and a mold material 3. The molding material 3 is formed integrally with the load detection unit 2, covers at least the surface of the load detection unit 2 in the collision direction, and can absorb at least a part of impact energy at the time of collision by elastic deformation. Yes.

  Patent Document 3 discloses a pedestrian collision detection device with improved detection accuracy, with reference to FIG. 1 and the explanation thereof. Specifically, the collision determination system includes a chamber member 20 that is arranged with the vehicle width direction as a longitudinal direction and that has a pressure chamber 22 inside. The chamber member 20 is disposed adjacent to the front surface 14 </ b> A of the bumper reinforcement 14. A bumper absorber 28 is disposed between the bumper cover and the bumper reinforcement 14. The bumper absorber 28 includes a main body portion 30 disposed in the lower portion and a gap filling portion 32 disposed in a gap between the chamber member 20 and the bumper cover.

Japanese Patent No. 2920284 JP 2006-125999 A JP 2011-143825 A

  However, with the above-described apparatus for collision detection, it may be difficult to accurately detect a collision with a person.

  Specifically, referring to FIG. 5 of Patent Document 1, as a general property of the molding material 3 (foam material), when collision energy is applied, the initial load is temporarily generated after the initial load is generated, and thereafter In some cases, the load increases again. Therefore, when a collision detection tube is disposed at the tip of the foam material, the tube is crushed halfway at the beginning of the collision, and then the foam material is sufficiently crushed and then the tube is crushed again. Therefore, since the stroke at the time of collision and the extent to which the tube is crushed (pressure fluctuation) are not suitably linked, it may be considered that detection of pedestrian collision at the initial stage of the collision becomes too sensitive and lacks accuracy.

  Moreover, the foam material used as an EA (Energy Absorption) material has a property which will be crushed from the front-end | tip part, when an impact acts dynamically. And the property has a positive correlation with the speed of the colliding vehicle. Therefore, if a tube for detecting a pedestrian collision is provided near the tip of the foam material, the property may adversely affect the detection of the pedestrian collision.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a pedestrian collision detection device with improved accuracy for detecting a collision.

  A pedestrian collision detection device according to the present invention includes a support member extending in a vehicle width direction, an impact absorbing member disposed in front of the support member, and disposed in the impact absorbing member, and is deformed by an impact acting on a vehicle. The shock absorbing member includes a front member facing forward, an upper member extending rearward from the upper portion of the front member, and a lower member extending rearward from the lower portion of the front member. And at least one of the upper member and the lower member has an inclined shape in which the rear part is further away from the horizontal line than the front part.

  In the present invention, at least one of the upper member and the lower member constituting the impact absorbing member has an inclined shape in which the rear part is further away from the horizon than the front part. Thereby, a sensor part can be crushed in an up-down direction because an upper member or a lower member opens at the time of a collision. Therefore, it becomes possible to detect the collision of the pedestrian with high accuracy by suitably linking the pressure of the sensor unit with respect to the stroke.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is a perspective view which shows the vehicle provided with the pedestrian collision detection apparatus, (B) is a perspective view which decomposes | disassembles and shows a pedestrian collision detection apparatus. It is. It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is sectional drawing which shows a pedestrian collision detection apparatus, (B) is sectional drawing which shows a foam material. It is a figure which shows the pedestrian collision detection apparatus of this invention, and is a block diagram which shows connection structures, such as various sensors which comprise a pedestrian collision detection apparatus. It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) is sectional drawing which shows the condition where a pedestrian collision detection apparatus operate | moves, (B) is a graph which shows the relationship between an approach amount and a pressure. . It is a figure which shows the pedestrian collision detection apparatus of this invention, (A) And (B) is sectional drawing which shows the pedestrian collision detection apparatus of another form. It is a figure which shows the pedestrian collision detection apparatus of this invention, and is sectional drawing which shows the pedestrian collision detection apparatus of another form.

  Hereinafter, the pedestrian collision detection device of the present embodiment will be described with reference to the drawings. In the following description, the left side and the right side indicate the left side and the right side when facing the traveling direction (front) of the vehicle.

  With reference to FIG. 1, the schematic structure of the pedestrian collision detection apparatus of this form is demonstrated. FIG. 1A is a perspective view showing a front end portion of the vehicle 10, and FIG. 1B is an exploded perspective view showing a pedestrian collision detection device 11 built in the front portion of the vehicle 10.

  With reference to FIG. 1 (A), the design part of the front part of the vehicle 10 is comprised from the upper part from the front hood 12, the grill 16, and the bumper skin 14. FIG. The pedestrian collision detection device 11 of this embodiment is provided behind the grill 16 or the bumper skin 14. And if the pedestrian collision detection apparatus 11 detects that the front-end part of the vehicle 10 collided with the pedestrian, the airbag arrange | positioned in the vicinity of the front hood 12 will inflate and deploy, and will protect a pedestrian from a secondary collision. .

  Referring to FIG. 1 (B), a pedestrian collision detection device 11 of the present embodiment includes a bumper support member 18 (support member) attached to the vehicle body side from the rear, and a foam disposed on the front surface of the bumper support member 18. A material 20 (impact absorbing member) and a detection tube 22 (sensor unit) incorporated in the front part of the foam material 20 are mainly provided. And the pedestrian collision detection apparatus 11 comprised from these members is arrange | positioned behind the bumper skin 14. FIG.

  The bumper support member 18 is a metal member extending in the width direction of the vehicle, and has a role of supporting the foam material 20 and the like and absorbing energy at the time of a large collision. In a pedestrian collision or a light collision, the bumper support member 18 is not deformed in principle.

  The foam material 20 is made of a resin material, and is continuously formed from the vicinity of the left end of the bumper support member 18 to the vicinity of the right end. As the material of the foam material 20, a foamed resin made of PP foam material or polyethylene is adopted. The foam material 20 has an action of absorbing an impact generated when a pedestrian collides. In this embodiment, the shape of the foam material 20 is such that the detection tube 22 can detect a pedestrian collision with high accuracy, and such matters will be described later.

  The detection tube 22 is a pipe-shaped resin member having a circular cross section, and the inside is sealed. The detection tube 22 is disposed from the vicinity of the right end of the bumper support member 18 to the vicinity of the left end. A pressure sensor (not shown) is arranged inside the detection tube 22 and detects a pedestrian collision by detecting a pressure fluctuation when the detection tube 22 is compressed by an impact at the time of a collision. doing. In this embodiment, the detection tube 22 is housed in a portion where the front surface of the foam material 20 is partially recessed, but the detection tube 22 may be built in the front portion of the foam material 20.

  With reference to FIG. 2, the structure of the pedestrian collision detection apparatus 11 of this form is explained in full detail. 2A is a cross-sectional view showing the structure of the pedestrian collision detection device 11 during normal running, and FIG. 2B is a cross-sectional view showing the foam material 20 extracted.

  With reference to FIG. 2 (A), as described above, the pedestrian collision detection device 11 includes the bumper support member 18, the foam material 20, the detection tube 22, and the bumper skin 14 from the rear.

The front surface of the bumper support member 18 is a substantially smooth surface, and a foam material 20 is provided on the front surface. The shape of the foam material 20 in a side view is roughly the shape of “KU” in Hiragana.
The front surface of the foam material 20 faces the bumper skin 14 and the rear surface faces the bumper support member 18. The detection tube 22 is stored in a storage portion 42 in which the vicinity of the center of the front surface of the foam material 20 is recessed backward. At the time of a pedestrian collision, the bumper skin 14 that collided with the thigh of the pedestrian is deformed rearward, and the foam material 20 pressed against the bumper skin 14 is compressed and deformed to absorb the impact. In addition, the detection tube 22 is compressed simultaneously with the compressive deformation of the foam material 20, and the pedestrian collision is detected by increasing the internal pressure.

  With reference to FIG.2 (B), the structure of the foam material 20 with which the above-mentioned pedestrian collision detection apparatus 11 is equipped is explained in full detail. The foam material 20 includes a front member 20A facing forward in the collision direction, an upper member 20B extending rearward from the upper end of the front member 20A, and a lower member 20C extending rearward from the lower end of the front member 20A. These members constituting the foam material 20 are integrally formed of a foamed resin.

  A storage portion 42 is formed by recessing the vicinity of the front center of the front member 20A rearward. The storage portion 42 is a part for storing the above-described detection tube 22 and is formed to have the same size as the detection tube 22.

  In this embodiment, the upper member 20B and the lower member 20C that are continuous rearward from the front member 20A are shaped so that the upper member 20B and the lower member 20C open rearward. Specifically, the extension line of the center line 21 indicating the center of the thickness of the upper member 20B in the vertical direction intersects with the horizontal line 24 at a predetermined angle θ1. Therefore, the upper member 20B is inclined such that the rear part is further away from the horizontal line 24 than the front part. On the other hand, the extension line of the center line 23 of the lower member 20C and the horizontal line 24 intersect at a predetermined angle θ2. Therefore, the lower member 20C is inclined so that the rear part is further away from the horizontal line 24 than the front part. Here, the horizontal line 24 indicates a horizontal line with respect to the vehicle 10 in which the foam material 20 is incorporated. The above-described θ1 and θ2 may be the same angle or different angles. Since the upper member 20B and the lower member 20C constituting the foam material 20 are inclined in this way, as will be described later, a pressure is applied to the detection tube 22 stored in the storage unit 42 in the vertical direction at the time of a collision. Can be given.

  Further, in this embodiment, the vertical width L1 of the front end portion of the foam material 20 is shorter than the width L2 of the rear end portion. As an example, L1 is less than or equal to half of L2. By making the front end of the foam material 20 narrower than the rear end in this way, a larger compressive force acts near the front end than at the rear end in the event of a collision. Part collapses preferentially over rear part. Thereby, it becomes possible to detect the collision with the pedestrian more accurately by the detection tube 22 disposed in the vicinity of the front end portion of the foam material 20.

  Referring to FIG. 3, the pressure inside detection tube 22 described above is measured by pressure sensor 19, and information indicating this pressure is output to ECU 15 (Electronic Control Unit). Information indicating the speed of the vehicle 10 is input to the ECU 15 from the speed sensor 13. This is because the pedestrian airbag 17 is deployed only when the vehicle speed is constant.

  The ECU 15 determines whether or not the vehicle 10 has collided with a pedestrian based on information obtained from these sensors. If it is determined that the vehicle 10 has collided with a pedestrian, the airbag 17 is inflated and deployed on the upper surface of the front hood 12 (see FIG. 1A) based on the output of the ECU 15 to protect the pedestrian.

  With reference to FIG. 4, a method will be described in which the pedestrian collision detection device 11 detects a collision with a pedestrian while the vehicle 10 is traveling. FIG. 4A is a cross-sectional view showing the pedestrian collision detection device 11 when a collision occurs, and FIG. 4B is a graph showing fluctuations in the pressure of the detection tube at the time of the collision.

  When the vehicle 10 collides with a pedestrian while traveling, the bumper skin 14 shown in FIG. 2A collides with the pedestrian and deforms backward. Then, the foam material 20 is compressed and deformed backward by the deformed bumper skin 14.

  With reference to FIG. 4 (A), the foam material 20 which deform | transforms at the time of this collision is demonstrated. In this figure, the foam material 20 after deformation is indicated by a solid line, and the foam material 20 before deformation is indicated by a dotted line.

  When the foam material 20 is pressed rearward from the front, the rear end side surface of the upper member 20 </ b> B slides upward with respect to the front surface of the bumper skin 14. Therefore, the angle at which the upper member 20B is inclined with respect to the horizontal line 24 (θ1 shown in FIG. 2B) is increased. Similarly, the rear end side surface of the lower member 20 </ b> C slides downward with respect to the front surface of the bumper skin 14. Therefore, the angle at which the lower member 20C is inclined with respect to the horizontal line 24 (θ2 shown in FIG. 2B) also increases. In other words, the upper member 20B and the lower member 20C are deformed so as to open in a side view.

  Along with the deformation of the upper member 20B and the lower member 20C, the front portion of the front member 20A undergoes compressive deformation. Therefore, a compressive force acts on the detection tube 22 accommodated in the accommodating portion 42 formed in this portion in the vertical direction. Accordingly, as the upper member 20B and the lower member 20C are opened by impact energy, a compressive force is applied to the detection tube 22 in the vertical direction.

  Moreover, the foam material 20 is compressed also in the front-back direction by the collision energy with a pedestrian acting. Therefore, at the time of a collision, a compressive force is applied to the detection tube 22 from the front-rear direction, and a compressive force is also applied from the vertical direction. Therefore, the amount of entry at the time of collision and the pressure of the detection tube 22 change well, and a pedestrian collision can be detected well.

  Further, as described above, since the upper member 20B and the lower member 20C are crushed while opening, almost the entire foam material 20 is crushed at the time of collision and less crushing remains, and more foaming energy is absorbed by the foam material 20. And the effect which protects a pedestrian becomes large.

  With reference to FIG. 4 (B), it becomes possible to make the relationship between the approaching amount at the time of collision and the internal pressure of the detection tube 22 closer to the ideal state by such a configuration. The horizontal axis of this graph represents the amount of entry during a pedestrian collision, and the vertical axis represents the internal pressure of the detection tube.

  In this graph, the ideal state is indicated by a dotted line. The ideal state is a proportional relationship between the approach amount and the pressure. With this relationship, it is possible to accurately detect a pedestrian collision based on the pressure of the sensor.

  Further, in this graph, a case where the upper member 20B and the lower member 20C shown in FIG. 4A are parallel to the horizontal line 24 is indicated by a one-dot chain line as a comparative example. This comparative example is in the same state as the ideal state in the initial stage D1 where the amount of entry is small, but in the subsequent intermediate period D2, the load acting on the detection tube 22 is temporarily stagnated so that the pressure fluctuation is reduced. At the end stage D3 of the collision, the rear part of the foam material 20 is almost crushed, so the front part of the foam material 20 is crushed again, and the detection tube 22 is compressed accordingly, and the internal pressure rises again.

  On the other hand, the pressure fluctuation of this embodiment provided with the foam material 20 having the configuration shown in FIG. In the present embodiment, the waveform shape is similar to that of the comparative example in all the periods D1-D3 described above, but the pressures higher than those of the comparative example are shown in the periods D2 and D3. The reason for this is that, in this embodiment, when the collision energy is applied, the upper member 20B and the lower member 20C are opened in the vertical direction, so that the detection tube 22 provided near the tip of the foam material 20 is moved up and down. This is because the pressure acting on the detection tube 22 is increased because the pressure is compressed in the direction. Thereby, in this form, since the internal pressure of the detection tube 22 becomes closer to an ideal state than a comparative example, it becomes possible to detect a pedestrian's collision with high precision.

  Another form of the pedestrian collision detection device 11 described above will be described with reference to FIG. 5A and 5B are cross-sectional views each showing another embodiment.

  Referring to FIG. 5A, in the foam material 20 shown in this figure, the angle at which the upper member 20B and the lower member 20C are inclined from the horizontal line 24 is different. Specifically, the angle θ1 at which the center line 21 of the upper member 20B intersects the horizontal line 24 is set smaller than the angle θ2 at which the center line 23 of the lower member 20C intersects the horizontal line 24. That is, the lower member 20 </ b> C is greatly inclined with respect to the horizontal line 24 than the upper member 20 </ b> B.

  By doing in this way, when the vehicle with which the foam material 20 is provided is a vehicle with a low vehicle height, the upper member 20B and the lower member 20C can be compressed more uniformly. Specifically, when a pedestrian collides with a vehicle having a low vehicle height, the direction in which the collision energy acts is not in the horizontal direction but in the direction inclined downward. The direction in which the collision energy acts is indicated by an arrow in FIG. In this embodiment, in such a case, the lower member 20C is inclined more greatly with respect to the horizontal line 24 than the upper member 20B, so that the upper member 20B and the lower member 20C are more uniformly opened to be compressed and stored. It becomes possible to compress the detection tube accommodated in the part 42 in the vertical direction.

  On the other hand, in the foam material 20 shown in FIG. 2B, the upper member 20B and the lower member 20C have substantially the same angle of inclination from the horizontal line, but such a structure is suitable for a passenger car having a high vehicle height. The reason for this is that, in the case of a passenger car with a high vehicle height, the collision energy acts horizontally on the foam material 20 at the time of a collision, whereby the upper member 20B and the lower member 20C are preferably opened. It is because it is obtained.

  In the foam material 20 shown in FIG. 5B, the rear side surfaces of the upper member 20 </ b> B and the lower member 20 </ b> C are inclined with respect to the front surface of the bumper support member 18. Specifically, the rear side surface of the upper member 20B has an inclined surface in which the lower portion is farther from the front surface of the bumper support member 18 than the upper portion. Similarly, the rear side surface of the lower member 20 </ b> C has an inclined surface in which the upper portion is farther from the front surface of the bumper support member 18 than the lower portion. With such a configuration, the area where the rear surfaces of the upper member 20B and the lower member 20C are in contact with the front surface of the bumper support member 18 is reduced, so that the frictional resistance between them is reduced. Therefore, at the time of a collision, the upper member 20B easily opens upward, and the lower member 20C easily opens downward. Therefore, the detection tube 22 stored in the storage unit 42 at the time of a collision is compressed well in the vertical direction, and a pedestrian collision can be detected more accurately.

  With reference to the cross-sectional view of FIG. Here, a stepped portion 25 is formed by partially denting the front surface of the bumper support member 18 rearward, and the rear end portions of the upper member 20B and the lower member 20C constituting the foam material 20 are applied to the stepped portion 25. Touching. As described above, at the time of a collision, the upper member 20B is deformed so as to open upward, and the lower member 20C is deformed so as to open downward. In the present embodiment, the rear end portions of the upper member 20B and the lower member 20C abut against the upper limit end portion of the step portion 25 at that time, so that these members are prevented from opening excessively. Accordingly, the upper member 20B and the lower member 20C are crushed well in the front-rear direction, and the effect of absorbing the collision energy with the foam material 20 is increased.

  Here, the above-described embodiments can be combined. For example, the rear end portion of the foam material 20 shown in FIG. 5 (A) may be an inclined surface as shown in FIG. 5 (B). Furthermore, the stepped portion 25 of the bumper support member 18 shown in FIG. 6 may be formed in the bumper support member 18 shown in another drawing.

  The above-described embodiment can be modified as follows, for example.

  Referring to FIG. 2B, the upper member 20B and the lower member 20C constituting the foam material 20 are formed to be inclined so as to spread rearward, but only one of them is formed to be inclined, and the other is formed. You may form in parallel with respect to the horizontal line 24. FIG.

10 Vehicle 11 Pedestrian Collision Detection Device 12 Front Hood 13 Speed Sensor 14 Bumper Skin 15 ECU
16 Grill 17 Airbag 18 Bumper support member 19 Pressure sensor 20 Foam member 20A Front member 20B Upper member 20C Lower member 21 Center line 22 Detection tube 23 Center line 24 Horizontal line 25 Step part 42 Storage part

Claims (5)

A support member extending in the vehicle width direction;
An impact absorbing member disposed in front of the support member;
A sensor unit disposed on the impact absorbing member and deformed by an impact acting on the vehicle,
The shock absorbing member has a front member facing forward, an upper member extending rearward from the upper portion of the front member, and a lower member extending rearward from the lower portion of the front member,
At least one of the upper member and the lower member is a pedestrian collision detection device characterized in that the rear part has an inclined shape that is further away from the horizon than the front part.   The pedestrian collision detection device according to claim 1, wherein the sensor unit is stored in a storage unit in which a front surface of the front member of the shock absorbing member is recessed.   The pedestrian collision detection device according to claim 1 or 2, wherein an angle at which the lower member is inclined with respect to the horizon is larger than an angle at which the upper member is inclined with respect to the horizon.   3. The pedestrian collision detection according to claim 1, wherein an angle at which the lower member is inclined with respect to the horizontal line is substantially the same as an angle at which the upper member is inclined with respect to the horizontal line. apparatus. The pedestrian collision detection device according to any one of claims 1 to 4, wherein a rear end surface of the upper member or the lower member is inclined with respect to a front surface of the support member.

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