JP2009227087A - Vehicle collision detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle collision detecting device for detecting a pressure change in a chamber arranged in a vehicle bumper, offering technology for discriminating the type of a colliding object with high accuracy. <P>SOLUTION: The vehicle collision detecting device comprises a chamber member 7 arranged in the vehicle bumper 1, a pressure sensor 9 for detecting pressure in a chamber space 7a, a vehicle speed sensor 11, and a controller 13. The controller 13 uses an approximate expression or a table showing a correlation between a maximum value for the pressure change detected by the pressure sensor 9 and the absorbing energy of the vehicle bumper for finding the absorbing energy of the vehicle bumper 1, uses an expression: M=2E<SB>1</SB>/V<SP>2</SP>for calculating an effective mass M of the colliding object from the absorbing energy E<SB>1</SB>, and discriminates the type of the colliding object to be a pedestrian when the effective mass M is a threshold value or greater or within its range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle collision detection device, and more particularly to a vehicle collision detection device that determines the type of a collision object based on a pressure change in a vehicle bumper.

  In recent years, for the purpose of protecting pedestrians, in order to protect pedestrians when a collision detection device is attached to the vehicle bumper, the type of collision object is determined at the time of collision with the vehicle, and it is determined that the vehicle is a pedestrian Techniques for operating these devices (for example, active hoods and cowl airbags) have been proposed, and their practical application has been studied.

  That is, when the collision object is not a pedestrian, various adverse effects occur when a protective device on the hood (for example, an active hood) is operated. For example, if it cannot be distinguished from a pedestrian when it collides with a lightweight fallen object such as a triangular cone or a signboard under construction, the protection device is activated wastefully and extra repair costs are generated. In addition, if it is indistinguishable from a pedestrian when it collides with a fixed wall such as a concrete wall or a vehicle, the hood will move backward with the hood lifted, so there is a risk that the hood may enter the passenger compartment and harm the passenger. is there. As described above, it is required to accurately determine the type of the collision object.

  2. Description of the Related Art Conventionally, a vehicle collision detection device has been proposed in which a chamber member is disposed in an absorber portion in a vehicle bumper and a type of a collision object is determined by detecting a pressure change in the chamber space at the time of a collision. (For example, see Patent Documents 1 and 2).

In these vehicle collision detection apparatuses described in Patent Documents 1 and 2, when an object collides with the vehicle bumper, the absorber (chamber member) disposed on the front surface of the bumper reinforcement is deformed in the bumper cover to absorb the impact. Is done. At this time, a pressure change is generated in the chamber due to the deformation of the absorber, and the pressure change is detected by the pressure sensor. And a collision detection apparatus discriminate | determines the kind (particularly whether it is a pedestrian) of a collision object based on the detection result of the pressure change by a pressure sensor. As described above, the type of the collision object is determined with a simple configuration by detecting the pressure change using the structure of the vehicle bumper. Further, even if the deformation amount of the chamber member at the time of the collision is small or regardless of the location of the collision, the collision can be detected with high accuracy.
JP 2007-290682 A JP 2007-290689 A

  However, as described above, in addition to pedestrians (people), objects that may collide with the bumper while the vehicle is running include a triangular cone, a signboard under construction, a concrete wall, other vehicles, etc. There are many kinds. In addition, since the degree of impact on the bumper varies depending on the traveling speed of the vehicle, it is necessary to determine the type of the collision object in consideration of the vehicle speed. Furthermore, since the object collides with the bumper surface while the vehicle is traveling, it is necessary to consider not only the chamber but also the influence of the bumper cover and the absorber. Moreover, since the bumper structure itself including such a bumper cover is different for each vehicle (vehicle type), it is desirable to detect a collision in consideration of the influence of each bumper structure. From such a point of view, it is desired to develop a technique that can more accurately determine the type of a collision object in a vehicle collision detection apparatus that detects a pressure change in a chamber using a sensor.

  The present invention has been made in view of the above problems, and in a vehicle collision detection device for detecting a pressure change in a chamber disposed in a vehicle bumper, the type of a collision object is determined with higher accuracy. It aims at providing the technology that can be.

  Hereinafter, each means suitable for solving the above-described problems will be described with additional effects and the like as necessary.

1. In a vehicle collision detection device configured to detect a collision of an object with a vehicle bumper,
A chamber member disposed in the vehicle bumper and having a chamber space formed therein;
A pressure sensor for detecting the pressure in the chamber space;
A vehicle speed sensor for detecting the vehicle speed of the vehicle;
Effective mass calculating means for calculating the effective mass of the collision object based on the detection results of the pressure sensor and the vehicle speed sensor;
A vehicle collision detection apparatus comprising: a determination unit that determines the type of the collision object based on the effective mass calculated by the effective mass calculation unit.

  Here, the “effective mass” means the mass of the portion of the total mass of the object that has collided with the vehicle bumper, to which energy related to the collision is applied to the vehicle bumper. Hereinafter, the term “effective mass” is used in the above meaning in the present specification.

  According to the means 1, since it is possible to determine the type of the collision object in consideration of the vehicle speed at the time of the collision detected by the vehicle speed sensor, it is possible to detect the collision with higher accuracy. Further, the effective mass of the collision object is calculated based on the detection results of the pressure sensor and the vehicle speed sensor, and the type of the collision object is determined based on the effective mass, so that the type of the collision object can be determined with high accuracy. it can.

2. An absorption energy acquisition means for obtaining an absorption energy of the vehicle bumper based on a maximum value of a pressure change in the chamber space detected by the pressure sensor;
The effective mass calculation means, the absorption energy of the vehicle bumper obtained by the absorbed energy obtaining unit and E _1, when the vehicle speed detection value of the vehicle speed sensor in the pressure change maximum point of the chamber space and is V, the ^2. The vehicle collision detection device according to claim 1, wherein the effective mass M is calculated by the mathematical formula M = 2E ₁ / V ² .

According to the means 2, the absorbed energy of the vehicle bumper is obtained based on the maximum value of the pressure change in the chamber space detected by the pressure sensor. In other words, since the type of the collision object is determined based on the maximum value of the pressure change in the chamber space, it is possible to perform highly accurate detection that eliminates the influence of noise and the like. Further, when the absorbed energy of the vehicle bumper obtained by the absorbed energy acquisition means is E ₁ and the vehicle speed detection value at the time of collision is V, the effective mass M is calculated by the formula M = 2E ₁ / V ² . Therefore, it is possible to calculate the effective mass of the collision object that is theoretically accurate in accordance with the equation of motion, thereby enabling accurate collision detection.

  3. The means for obtaining absorbed energy obtains the absorbed energy using an approximate expression or a table indicating a correlation between a maximum value of pressure change in the chamber space and the absorbed energy of the vehicle bumper. Vehicle collision detection device.

  According to the means 3, since the absorption energy of the vehicle bumper is obtained using an approximate expression or table indicating the correlation between the maximum value of the pressure change in the chamber space and the absorption energy of the vehicle bumper, the collision object is more accurately detected. The type can be determined. For example, it is possible to accurately detect a collision reflecting the shape and arrangement of the chamber member and the influence of other members such as a bumper cover and an absorber disposed in the vehicle bumper.

  4). 4. The vehicle collision detection apparatus according to claim 3, wherein the approximate expression or table is obtained in advance by a collision experiment with the vehicle bumper.

  According to the means 4, in addition to the chamber member, for example, the approximate expression or the table for each bumper structure can be obtained by a collision experiment with an actual vehicle bumper provided with a bumper cover, an absorber, or the like. Therefore, it is possible to provide a vehicle collision detection device capable of highly accurate detection according to the structure of the vehicle bumper when actually mounted on a vehicle.

  5). The vehicle bumper according to claim 3, wherein an absorber is further disposed in the vehicle bumper, and the approximate expression or the table is obtained in advance by a collision test between the absorber and the chamber member. Detection device.

  According to the means 5, since the bumper cover design may differ depending on the vehicle destination and grade, only the upper reinforcement portion is obtained by using the result of the collision test with only the absorber and the chamber member excluding the bumper cover. The approximate expression or table can be used, and can be handled by a common approximate expression or table regardless of the vehicle type.

  Hereinafter, an embodiment in which a vehicle collision detection device of the present invention is embodied will be described in detail with reference to the drawings.

  A vehicle collision detection device according to an embodiment of the present invention is a device configured to detect a collision of an object with a vehicle bumper 1 as shown in FIGS. 1 and a chamber member 7 in which a chamber space 7a is formed, a pressure sensor 9 for detecting the pressure in the chamber space 7a, a vehicle speed sensor 11 for detecting the vehicle speed of the vehicle, and a controller 13. ing. The controller 13 discriminates the type of the collision object based on the effective mass calculated by the effective mass calculation means and the effective mass calculation means for calculating the effective mass of the collision object based on the detection results of the pressure sensor 9 and the vehicle speed sensor 11. It functions as a discrimination means. Thus, in this embodiment, the controller 13 mounted on the vehicle functions as an effective mass calculation unit and a determination unit. As shown in FIG. 1B, the controller 13 is connected to the pedestrian protection device 21 and also functions as a controller (control means) of the pedestrian protection device 21. That is, in the example shown in FIG. 1, the vehicle is equipped with a pedestrian protection device 21 such as an active hood or a cowl airbag, and the pedestrian protection device 21 is controlled by a control signal output from the controller 13. The pedestrian protection operation is performed.

  As shown in FIG. 1, the vehicle bumper 1 is mainly composed of a bumper cover 2, a bumper reinforcement 3, a chamber member 7, and a side member (not shown). In the present embodiment, the chamber member 7 is formed integrally with the absorber.

  The bumper cover 2 is a resin (for example, polypropylene) cover member that extends in the vehicle width direction at the front end of the vehicle and is attached to the vehicle body so as to cover the bumper reinforcement 3 and the chamber member 7.

  The bumper reinforcement 3 is a metal beam-like member that is disposed in the bumper cover 2 and extends in the vehicle width direction.

  The side members are a pair of metal members that are located on the side surface of the vehicle and extend in the vehicle front-rear direction, and the bumper reinforcement 3 described above is attached to the front end thereof.

  The chamber member 7 is a member that is attached to the front surface of the bumper reinforcement 3 in the bumper cover 2 and has both the effects of shock absorption and pressure transmission in the vehicle bumper 1. The chamber member 7 has a chamber space 7a formed therein, and air is sealed in the chamber space 7a. A pressure receiving portion of the pressure sensor 9 is inserted into the chamber space 7a through an insertion port. In the present embodiment, the vehicle front side portion of the chamber member 7 also serves as an absorber, but the absorber may be separately disposed on the surface of the chamber member on the vehicle front side. As a material for the absorber portion or the like of the chamber member 7, a material harder than the chamber portion, for example, a metal such as an iron plate, a foamed resin, or the like can be used.

  The pressure sensor 9 is a sensor device that can detect a gas pressure, and is assembled to the chamber member 7. Specifically, the pressure receiving portion is inserted into the chamber space 7a via the insertion port, and the pressure change of the air in the chamber space 7a can be detected. The pressure sensor 9 outputs a signal proportional to the pressure. The pressure sensor 9 is electrically connected to the controller 13 via the transmission line 9a.

  The vehicle speed sensor 11 is a known speed sensor that can detect the traveling speed of the vehicle, and is electrically connected to the controller 13 via the transmission line 11a. In this embodiment, a wheel speed sensor is used.

  The controller 13 is an electronic control device for performing deployment control of the above-described cowl airbag or the like when the type of the collision object is determined to be a pedestrian, and signals output from the pressure sensor 9 and the vehicle speed sensor 11 are transmitted. It is configured to be input via lines 9a and 11a, respectively. As described above, the controller 13 calculates the effective mass of the collision object based on the detection results of the pressure sensor 9 and the vehicle speed sensor 11, and executes a process of determining the type of the collision object based on the calculated effective mass. The controller 13 outputs a control signal for operating the pedestrian protection device 21 when the type of the collision object is determined to be a pedestrian. The pedestrian protection device 21 performs the pedestrian protection operation according to the control signal output from the controller 13. Specifically, the active hood is activated or the cowl airbag is deployed on the windshield of the vehicle.

  Next, in the vehicle collision detection apparatus of the present embodiment, a process for determining the type of the collision object when an object collides with the vehicle bumper 1 will be described.

  When the collision of the object with the vehicle bumper 1 occurs, the chamber member 7 at the collision portion is crushed, and the gas pressure in the chamber space 7a increases (that is, changes). A change in gas pressure in the chamber space 7a is detected by the pressure sensor 9. The controller 13 takes in a signal output from the pressure sensor 9 through the transmission line 9a and takes in a vehicle speed signal from the vehicle speed sensor 11 through the transmission line 11a. The controller 13 calculates the effective mass of the collision object based on the output from the pressure sensor 9 and the vehicle speed, and whether or not the collision object is a pedestrian or the like depending on whether or not the calculated effective mass is within a predetermined threshold. Is determined.

  In other words, since the effective mass is different between the human body and another collision object, the maximum value (peak value) of the analog output of the pressure sensor 9 is different. Therefore, the effective mass of the collision object is calculated from the output of the pressure sensor 9, and for this effective mass, a threshold value is set between the mass of the human body and the mass of the other collision object that is assumed. It is possible to separate the types. However, since the output of the pressure sensor 9 (in other words, the amount of deformation of the chamber member 7) depends on the energy of the impact caused by the collision with a certain effective mass at a certain speed, the vehicle speed at the time of the collision is also taken into account. To calculate the effective mass.

Hereinafter, the calculation method of the effective mass in this embodiment is demonstrated in detail. In the vehicle collision detection apparatus of the present embodiment, the controller 13 shown in FIG. 1B functions as the above-described effective mass calculation means and determination means, and in addition, the chamber space 7a detected by the pressure sensor 9 is used. It functions as an absorbed energy acquisition means for determining the absorbed energy of the vehicle bumper 3 based on the maximum value of the pressure change at. The controller 13, as the effective mass calculation means, the absorption energy of the vehicle bumper 1 determined by the absorbed energy acquiring unit and E _1, when the vehicle speed detection value at the time of collision was is V, formula effective mass M M = calculated by _2E 1 / ^{V 2.}

  That is, the present inventor, from the essential function of the vehicle bumper, pays attention to the fact that the kinetic energy of the collision object is absorbed by the vehicle bumper due to the collision of the object with the vehicle bumper, and if the absorbed energy of the vehicle bumper is obtained, Since the kinetic energy of the colliding object is obtained by the equation of motion, the mass of the colliding object (the mass here is the mass of the part of the total mass of the object that collided with the vehicle bumper, to which the energy related to the collision is applied to the vehicle bumper. In the sense, it was theoretically found that the “effective mass” of the collision object can be obtained more accurately.

  Hereinafter, a method for obtaining the absorbed energy of the vehicle bumper will be described in an easy-to-understand manner with reference to FIGS.

First, the kinetic energy E of the collision object is
[Number ^{1] E = 1MV 2/2} --------- (1)
It is represented by

  As shown in FIG. 2, when a collision object of a certain mass M collides with the vehicle bumper 1 at the collision speed (vehicle speed detection value by the vehicle speed sensor) V, the vehicle bumper 1 is deformed by ΔS due to the collision load F. When the chamber member 7 is crushed and the volume of the chamber space 7a changes by ΔV, the pressure sensor 9 detects the pressure change ΔP.

On the other hand, the relationship between the collision load F [t] and the bumper deformation amount ΔS [mm] is as shown in the graph of FIG. 3, and the area of the hatched portion in the graph corresponds to the absorbed energy E ₁ of the bumper. . That is, absorbed energy E ₁ of the bumper, the integrated value of the impact load F for the bumper deformation amount [Delta] S,
[Equation 2] ∫Fds = E ₁ --------- (2)
It is represented by

"Effective mass" of the relationship be defined as described above for colliding object, from being absorbed on all the kinetic energy E of the colliding object bumper can be said to become absorbed energy E ₁ of the bumper, the (1), (2) Therefore, the effective mass M is
From [Number _{^{3] 1MV 2/2 = E}} 1 --------- (3),
[Equation 4] M = 2E ₁ / V ² --------- (4).

As described above, the absorbed energy of the vehicle bumper 1 is obtained based on the maximum value of the pressure change in the chamber space 7a detected by the pressure sensor 9, and the absorbed energy of the vehicle bumper obtained by the absorbed energy acquisition means is calculated as E. _1, and when the vehicle speed detection value at the time of collision was V, and effective mass M, because calculated by formula M = 2E 1 _/ V ^2, the effective mass of the theoretically correct collided object even in line with the equation of motion Can be calculated, which enables accurate collision detection.

  As described above, theoretically accurate collision detection is possible. However, as described above, since the object collides with the bumper surface while the vehicle is running, not only the chamber but also more accurately. It is desirable to detect the collision in consideration of the influence of each bumper structure including the bumper cover in consideration of the influence of the bumper cover and the absorber.

Therefore, the controller 13 functioning as the absorbed energy acquisition means further uses the approximate expression showing the correlation between the maximum value ΔP _max of the pressure change in the chamber space 7a and the absorbed energy E ₁ of the vehicle bumper 1 to use the absorbed energy E _1. I asked for.

First, in order to confirm that a certain correlation is obtained between the maximum value ΔP _max of the pressure change in the chamber space 7 a and the absorbed energy E ₁ of the vehicle bumper 1, the inventor performs a collision experiment on the vehicle bumper 1. Carried out.

FIG. 4 is a diagram for explaining the relationship between the maximum value ΔP _max of the pressure change in the chamber space and the absorbed energy E ₁ of the vehicle bumper 1, and (a) shows the conditions of the collision experiment on the vehicle bumper 1. (B) is a graph showing the correlation between the maximum value ΔP _max of the pressure change in the chamber space 7a and the absorbed energy E ₁ of the vehicle bumper 1 obtained by the collision experiment under the conditions. .

As shown in FIG. 4 (a), experimental impactors with mass m of 2 kg, 5 kg, and 8 kg are prepared, respectively. With an impactor with a collision speed v of 2 kg, two types of collisions of 25 [km] and 40 [km] are performed. Collision with vehicle bumper 1 at two impact speeds of 25 [km] and 40 [km] per hour, as with a 2 kg impactor, at one impact speed of 40 [km] per hour for an impactor of 5 kg Thus, the relationship between the maximum value ΔP _max of the pressure change in the chamber space 7a and the absorbed energy E ₁ of the vehicle bumper 1 was considered.

As a result of the experiment, as shown in FIG. 4B, it is confirmed that the absorbed energy E ₁ of the vehicle bumper 1 has a certain correlation with the maximum value ΔP _max of the pressure change in the chamber member 7. did it. Figure 4 graphs (b), in particular, absorbed energy E ₁ of the vehicle bumper 1 to the extent 300 [J] could be obtained effectively is certain correlation. Therefore, from the graph of FIG. 4B, on the premise of the bumper structure of the vehicle bumper 1 used in this experiment, the correlation between the maximum value ΔP _max of the pressure change in the chamber space 7a and the absorbed energy E ₁ of the vehicle bumper 1. It is possible to obtain an approximate expression indicating Therefore, in the present embodiment, the controller 13 that functions as the absorbed energy acquisition means obtains the absorbed energy of the vehicle bumper 1 using such an approximate expression. Specifically, this approximate expression is held in a memory (not shown) or the like in the controller 13, and using this approximate expression, the absorbed energy of the vehicle bumper 1 is calculated from the maximum value of the pressure change detected by the pressure sensor 9. Ask.

Thus, since obtaining the absorption energy E ₁ of the vehicle bumper using an approximate equation representing the correlation between the absorption energy E ₁ of the maximum value [Delta] P _max and the vehicle bumper 1 of the pressure change in the chamber space 7a, a more accurate collision The type of the object can be discriminated. For example, it is possible to accurately detect a collision reflecting the influence of the shape and arrangement of the chamber member, and other members such as a bumper cover disposed on the vehicle bumper and a foamed resin absorber.

  The approximate expression is obtained in advance by the above-described collision experiment with the vehicle bumper 1. That is, in addition to the chamber member 7, for example, an approximate expression obtained for each bumper structure is used by a collision experiment with an actual vehicle bumper in which the bumper cover 2, foamed resin absorber, or the like is disposed. Therefore, when actually mounted on a vehicle, it is possible to detect a collision with high accuracy in accordance with the structure of the vehicle bumper 1.

  Further, an absorber is disposed in the vehicle bumper 1, and the approximate expression may be obtained in advance by a collision experiment between the absorber and the chamber member 7. The bumper cover design may vary depending on the vehicle destination and grade, so use the result of the collision test only on the absorber and the chamber member excluding the bumper cover, and use the approximation formula only for the upper reinforcement part. And can be handled by a common approximate expression regardless of the type of vehicle.

  In the above example, the approximate expression obtained in advance by the collision experiment on the vehicle bumper 1 or the collision experiment only on the absorber and the chamber member 7 is held in the memory or the like in the controller 13. A table indicating the relationship may be used, and the table may be held in a memory or the like in the controller 13.

  Next, the process flow of the controller 13 in the vehicle collision detection device will be described. FIG. 5 is a flowchart showing the processing of the controller 13. The controller 13 stores in advance a collision detection program in a memory (not shown) or the like, and a CPU (not shown) executes each process described below according to the program.

  As shown in FIG. 5, the controller 13 performs a process for initializing a calculation value (initial value setting process such as an initial value of each sensor) as an initial process (step S-1).

Subsequently, the controller 13 reads the vehicle speed detection value V detected by the vehicle speed sensor 11 (step S-2), and determines whether or not the vehicle speed detection value V is within a predetermined threshold value (minimum value and maximum value). Judgment is made (step S-3). This is because the speed at which the pedestrian protection function such as the above-described pedestrian protection device acts effectively is determined by the vehicle shape and the like, so that the collision is detected only when the speed is within such a range. is there. When the vehicle speed detection value V is within a predetermined threshold (minimum value and maximum value) (Yes in step S-3), the pressure detection value P [t] detected by the pressure sensor 9 is read (step S). -4) The maximum value (peak value) of the pressure change is calculated from the detected pressure value P [t] (step S-5). Then, the controller 13, as absorbed energy obtaining means described above, by using an approximate expression as described above, by calculating the absorbed energy E ₁ corresponding to the maximum value of the pressure change that is calculated in step S-5 (peak value) Obtained (step S-6). Subsequently, the controller 13 calculates the effective mass M of the collision object from the obtained absorbed energy E _{1 as} the above-described effective mass calculating means by using the mathematical formula M = 2E ₁ / V ² (step S-7). Then, the controller 13 determines whether the calculated effective mass M is equal to or greater than a predetermined threshold (step S-8) as a determination unit. If the calculated effective mass M is equal to or greater than the threshold (Yes in step S-8), It is detected that the vehicle collides with a pedestrian, that is, the type of the collision object is determined as a pedestrian (step S-9). On the other hand, if it is not equal to or greater than the threshold (No in step S-8), it is detected that the vehicle collides with a person other than a pedestrian, that is, the type of colliding object is determined as an object other than a pedestrian (step S-10). Here, for example, when the threshold value for discriminating a pedestrian of effective mass M is less than 2 kg, it is discriminated as an object other than a pedestrian. Unlike the case of step S-8 in the figure, for example, in the case of 10 kg or more, it may be determined that the object is not a pedestrian. Alternatively, unlike the case of step S-8 shown in the figure, if it is within a predetermined range, for example, within a range of 2 kg to 10 kg, it may be determined as a pedestrian.

  As is apparent from the above description, according to the present embodiment, when a collision object collides with the vehicle bumper 1, the chamber member 7 (also serving as an absorber) disposed in front of the bumper reinforcement 3 in the bumper cover 2 is used. The impact is absorbed by deformation. At this time, a pressure change occurs in the chamber space 7 a due to the deformation of the chamber member 7, and the pressure change is detected by the pressure sensor 9. Then, the controller 13 calculates the effective mass of the collision object based on the detection result of the pressure change by the pressure sensor 9 and the detection result of the vehicle speed by the vehicle speed sensor 11, and whether or not the calculated effective mass is within a predetermined threshold value. Thus, it is possible to determine with high accuracy whether or not the collision object is a pedestrian. That is, according to the present embodiment, it is possible to accurately determine the type of the collision object with a simple configuration by detecting the pressure change using the structure of the vehicle bumper 1.

  Further, according to the present embodiment, it is possible to determine the type of the collision object in consideration of the vehicle speed at the time of the collision detected by the vehicle speed sensor, so that the collision detection with higher accuracy can be performed. Further, the effective mass of the collision object is calculated based on the detection results of the pressure sensor and the vehicle speed sensor, and the type of the collision object is determined based on the effective mass, so that the type of the collision object can be determined with high accuracy. it can.

  Further, according to the present embodiment, it is possible to calculate the effective mass of a collision object that is theoretically accurate in accordance with the equation of motion, and thus it is possible to accurately detect a collision. Also, since the absorption energy of the vehicle bumper is obtained using an approximate expression or table showing the correlation between the maximum value of the pressure change in the chamber space and the absorption energy of the vehicle bumper, compared to the case where the approximate expression or table is not used. Therefore, it is possible to more accurately determine the type of the collision object. For example, it is possible to accurately detect a collision reflecting the influence of the shape and arrangement of the chamber member, and other members such as a bumper cover disposed on the vehicle bumper and a foamed resin absorber. Furthermore, since the approximate expression or the table is obtained in advance by a collision experiment with the vehicle bumper, for example, an actual vehicle bumper provided with a bumper cover, a foamed resin absorber, etc. in addition to the chamber member. An approximate expression or table for each bumper structure can be obtained by a collision experiment on the bumper structure. Therefore, it is possible to provide a vehicle collision detection device capable of highly accurate detection according to the structure of the vehicle bumper when actually mounted on a vehicle.

  Further, an absorber is disposed in the vehicle bumper 1, and the approximate expression or the table may be obtained in advance by a collision experiment between the absorber and the chamber member 7. The bumper cover design may vary depending on the vehicle destination, grade, etc., so by using the result of a collision test with only the absorber and chamber member excluding the bumper cover, an approximate expression or table only for the upper reinforcement part can be obtained. It can be used and can be handled by a common approximate expression or table regardless of the type of vehicle.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the main point of this invention. For example, in the above-described embodiment, the configuration in which air is sealed in the chamber member 7 is shown, but a configuration in which a gas other than air is sealed may be employed.

  The present invention can be applied to a vehicle collision detection device that can identify a collision object based on a pressure change in a vehicle bumper.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the collision detection apparatus for vehicles which concerns on embodiment of this invention, (a) is a figure which shows the structure with the schematic longitudinal cross-section of a vehicle bumper, (b) is the functional block diagram. . It is a conceptual diagram for demonstrating the method of calculating effective mass in embodiment of this invention. It is a graph which shows the relationship between a collision load and bumper deformation. It is a figure for demonstrating the relationship between the maximum value of the pressure change in a chamber space, and the absorbed energy of a vehicle bumper, (a) is a figure which shows simply the conditions of the collision experiment to a vehicle bumper, (b) is FIG. 5 is a graph showing a correlation between a maximum value of a pressure change in a chamber space obtained by a collision experiment under the condition and an absorbed energy of a vehicle bumper. It is a flowchart which shows the process of the controller in the collision detection apparatus for vehicles which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle bumper 2 Bumper cover 3 Bumper reinforcement 7 Chamber member 7a Chamber space 9 Pressure sensor 11 Vehicle speed sensor 13 Controller (Effective mass calculation means, discrimination means, absorbed energy acquisition means)

Claims (5)

In a vehicle collision detection device configured to detect a collision of an object with a vehicle bumper,
A chamber member disposed in the vehicle bumper and having a chamber space formed therein;
A pressure sensor for detecting the pressure in the chamber space;
A vehicle speed sensor for detecting the vehicle speed of the vehicle;
Effective mass calculating means for calculating the effective mass of the collision object based on the detection results of the pressure sensor and the vehicle speed sensor;
A vehicle collision detection apparatus comprising: a determination unit that determines a type of the collision object based on the effective mass calculated by the effective mass calculation unit. An absorption energy acquisition means for obtaining an absorption energy of the vehicle bumper based on a maximum value of a pressure change in the chamber space detected by the pressure sensor;
The effective mass calculating means sets the effective mass M to the mathematical expression M = 2E ₁ / when the absorbed energy of the vehicle bumper obtained by the absorbed energy acquiring means is E ₁ and the vehicle speed detection value at the time of collision is V. The vehicle collision detection device according to claim 1, wherein the vehicle collision detection device is calculated from V ² .   3. The absorbed energy obtaining means obtains the absorbed energy using an approximate expression or table showing a correlation between a maximum value of pressure change in the chamber space and absorbed energy of the vehicle bumper. The vehicle collision detection device as described.   The vehicle collision detection device according to claim 3, wherein the approximate expression or the table is obtained in advance by a collision experiment with the vehicle bumper.   The vehicle bumper according to claim 3, wherein an absorber is further disposed in the vehicle bumper, and the approximate expression or the table is obtained in advance by a collision test between the absorber and the chamber member. Collision detection device.

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