JP2009208642A - Vehicle collision detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle collision detector preventing pressure in a chamber space from being reduced immediately after collision and improving collision detection accuracy. <P>SOLUTION: This vehicle collision detector includes a chamber member 7 arranged on the front surface 4a of a bumper reinforcement 4 in a vehicle bumper 2 and having the chamber space 7a formed inside thereof, and a pressure sensor 8 detecting pressure in the chamber space 7a, and is configured to detect collision with the vehicle bumper 2 based on a result detected by the pressure sensor 8. The chamber member 7 has a cross section formed into a substantially rectangular outer edge shape when viewed from a vehicle width direction. In the outer edge shape, longitudinal width (b) in a vertical direction is wider than lateral width (a) in a vehicle longitudinal direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In recent years, for the purpose of protecting pedestrians, in order to protect pedestrians, if an obstacle discriminating device is attached to the vehicle bumper part, it is determined whether or not the collision target is a pedestrian at the time of a vehicle collision. 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 obstacle which collided is not a pedestrian, various bad influences will arise if the protective device (for example, active hood) on a 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 cannot be distinguished from a pedestrian when it collides with a fixed weight object such as a concrete wall or a vehicle, the hood moves back in a lifted state, so that the hood may enter the vehicle interior. Thus, it is required to accurately classify whether or not the obstacle is a pedestrian.

Therefore, as described in, for example, Japanese Patent Application Laid-Open No. 2006-117157 (Patent Document 1), a chamber member is disposed in front of the bumper reinforcement in the vehicle bumper, and a pressure sensor detects the pressure change in the chamber space. There has been proposed a vehicle collision detection device configured to detect a collision of a pedestrian or the like with a vehicle bumper. That is, the chamber member is deformed by the collision, and the collision of a pedestrian or the like is detected based on the pressure change in the chamber space.
JP 2006-117157 A

  As described above, the vehicle collision detection device detects a pressure change in the chamber space accompanying the deformation of the chamber member. Generally, a chamber member is deformed in a collapsing direction with respect to a collision. That is, when a collision occurs, the chamber member is deformed as the volume of the chamber space decreases, and the pressure in the chamber space increases. Therefore, for example, the normal pressure in the chamber space is used as a reference value, and it is desirable to change the threshold value to the plus side of the reference value (normally, the threshold value is preferably changed according to the vehicle speed. ) And can be designed to be determined to be a collision when the pressure in the chamber space exceeds the threshold.

  However, depending on the shape of the chamber member, there is a case where the chamber member is deformed in a direction in which it immediately swells immediately after a collision, and the volume of the chamber space increases. In such a chamber member, the pressure change immediately after the collision is on the negative side. That is, the pressure once becomes smaller than the reference value immediately after the collision, and then becomes larger. Immediately after the collision, the chamber member is deformed in the direction in which it swells, so that the pressure once becomes smaller than the reference value, and the amount of pressure change to the plus side due to the collapse is reduced accordingly.

  When the chamber member that swells instantaneously immediately after the collision as described above is used, the pressure change to the plus side due to the collision deformation becomes small, so the threshold value must be set to a value closer to the reference value. In this case, for example, it is difficult to distinguish between a pressure change due to a collision and a pressure change due to noise, and it is difficult to improve the accuracy of collision detection.

  The present invention has been made in view of such circumstances, and provides a vehicle collision detection device capable of preventing a pressure in a chamber space from decreasing immediately after a collision and improving collision detection accuracy. With the goal.

  A vehicle collision detection apparatus according to the present invention includes a chamber member that is disposed in front of a bumper reinforcement in a vehicle bumper and that has a chamber space formed therein, and a pressure sensor that detects a pressure in the chamber space. In the vehicle collision detection device that is configured to detect a collision with the vehicle bumper based on the detection result of the pressure sensor, the chamber member has a substantially rectangular outer edge shape as viewed from the vehicle width direction. In the outer edge shape, the vertical width in the vertical direction is equal to or greater than the horizontal width in the vehicle front-rear direction.

  In response to a collision from the front of the vehicle, the chamber member immediately after the collision is deformed in a direction in which both the front and rear sides of the vehicle collapse toward the inside of the chamber space and a direction in which the upper and lower surfaces swell outward from the chamber space due to the moment applied to the corner. To do. That is, in the chamber member, immediately after the collision, the front and rear surfaces of the vehicle are bent inward to reduce the volume, and the upper and lower surfaces are bent outward to increase the volume.

  In the present invention, the outer circumferential shape of the cross section of the chamber member viewed from the vehicle width direction is substantially rectangular, and in the outer edge shape, the vertical width b in the vertical direction is equal to or greater than the lateral width a in the vehicle front-rear direction (b ≧ a). ing. The vertical width a in the vertical direction in the outer edge shape corresponds to the length of each side located in the front and rear direction of the vehicle in the outer edge shape. Further, the lateral width b in the vehicle front-rear direction in the outer edge shape corresponds to the length of each side located above and below in the outer edge shape. In the outer edge shape, immediately after the collision, the front and rear sides of the vehicle are bent inward to reduce the area, and the upper and lower sides are bent outward to increase the area.

Here, assuming that the amount of deflection in the vehicle front-rear direction immediately after the collision is δ _x and the amount of deflection in the vertical direction is δ _y , in the outer edge shape, the area where the chamber deformation amount becomes small immediately after the collision is very small is expressed approximately 2bδ _x, larger area can be expressed approximately 2aδ _y. When 2bδ _x ≧ 2aδ _y is satisfied, the area of the cross section (outer edge shape) does not increase immediately after the collision, and as a result, the chamber space is prevented from increasing in volume.

Here, the amount of deflection is proportional to the square of the length of each side. Therefore, the conditional expression is b ³ ≧ a ³ and b ≧ a. Thus, in the present invention, the condition that the area of the cross section (outer edge shape) does not increase immediately after the collision (b ≧ a) is satisfied, and the volume of the chamber space does not increase immediately after the collision.

  That is, according to the present invention, it is possible to prevent the pressure in the chamber space from decreasing immediately after the collision. Thereby, the threshold value can be set to a value far away from the normal pressure value (reference value) without decreasing the pressure change amount to the plus side due to the collision. In other words, it is possible to reliably perform a separation from a pressure change due to other than a collision (such as noise), prevent erroneous determination, and perform highly accurate collision detection.

  By the way, in the vehicle collision detection apparatus, an absorber may be disposed on the upper surface side or the lower surface side of the chamber member. In this case, at the time of collision, the upper surface (or lower surface) of the chamber member on which the absorber is disposed cannot be bent outward by the absorber. In view of this, the present invention can be configured as follows.

  That is, the vehicle collision detection device of the present invention is disposed on the front surface of the bumper reinforcement in the vehicle bumper and the chamber space is formed therein, and is disposed on the upper surface side or the lower surface side of the chamber member. In the vehicle collision detection device, the chamber member is configured to detect a collision with the vehicle bumper based on a detection result of the pressure sensor. The outer edge shape of the cross section viewed from the vehicle width direction is substantially rectangular. In the outer edge shape, when the vertical width in the vertical direction is b and the horizontal width in the vehicle front-rear direction is a,

が成立することを特徴とする。

Is established.

  For example, when the absorber is disposed on the lower surface side of the chamber member, deformation of the lower surface of the chamber member due to the collision is restrained by the absorber. Therefore, at the time of collision, the lower surface hardly bends outward, and the volume on the lower surface side hardly increases. That is, in the chamber member immediately after the collision, both the front and rear surfaces of the vehicle bend inward, and only the upper surface of the upper and lower surfaces bends outward.

Here, when considered as if there were no absorber, at the outer edge shape, small area represented approximately 2Bideruta _x, larger area can be expressed approximately A-delta _y. By satisfying 2bδ _x ≧ aδ _y , the area of the cross section (outer edge shape) does not increase immediately after the collision, and as a result, the chamber volume is prevented from increasing. Here, since the amount of deflection is proportional to the square of the length of each side, the conditional expression is 2b ³ ≧ a ³ , which is the above expression (Formula 1). This is the same even when the absorber is arranged on the upper surface side of the chamber member.

  Thus, in the present invention, the condition that the area of the cross section (outer edge shape) does not increase immediately after the collision (Equation 1) is satisfied, and the volume of the chamber space does not increase immediately after the collision. That is, it is possible to prevent the pressure in the chamber space from decreasing immediately after the collision and improve the collision detection accuracy.

  Here, in this invention, it is preferable that the chamber member is integrally molded by blow molding using a resin material. Thereby, even if a chamber member is the said shape, it can produce more easily.

  According to the vehicle collision detection device of the present invention, it is possible to prevent the pressure in the chamber space from decreasing immediately after the collision and to improve the collision detection accuracy.

  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.

<First embodiment>
A first embodiment will be described with reference to FIGS. FIG. 1 is a plan view schematically showing a vehicle collision detection apparatus 1 according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 3 is a cross-sectional view taken along line BB in FIG. FIG. 4 is a view showing an outer edge of the chamber member 7 immediately after the collision in FIG. However, the bumper cover 3 and the side member 5 are omitted in FIGS.

  As shown in FIG. 1, the vehicle collision detection device 1 includes a chamber member 7 disposed in a vehicle bumper 2, a pressure sensor 8, a pedestrian protection device electronic control unit (hereinafter referred to as an electronic control unit as an ECU). (Abbreviated) 10 as a main component.

  As shown in FIGS. 1 and 2, the vehicle bumper 2 is mainly composed of a bumper cover 3, a bumper reinforcement 4, a side member 5, and a chamber member 7.

  The bumper cover 3 is a resin (for example, polypropylene) cover member that extends in the vehicle width direction (left-right direction) at the front end of the vehicle and is attached to the vehicle body so as to cover the bumper reinforcement 4 and the chamber member 7.

  The bumper reinforcement 4 is a metal structural member that is disposed in the bumper cover 3 and extends in the vehicle width direction, and as shown in FIG. It is a hollow member which has.

  The side members 5 are a pair of metal members that are positioned in the vicinity of the left and right side surfaces of the vehicle and extend in the vehicle front-rear direction, and the bumper reinforcement 4 described above is attached to the front end thereof.

  The chamber member 7 is a substantially box-shaped synthetic resin member that extends in the vehicle width direction and is attached to the bumper reinforcement front surface 4a in the bumper cover 3, and is substantially hermetically enclosed by a wall having a thickness of several millimeters. The chamber space 7a is formed.

  More specifically, the chamber member 7 includes a main body portion 71 and an extending portion 72. The main body 71 is a portion disposed in front of the bumper reinforcement front surface 4a, and extends in the vehicle width direction. That is, the main body 71 is a part that is deformed by a collision, and a pressure change in the main body 71 is detected as a pressure change in the chamber space 7a. The main body 71 corresponds to a “chamber member” in the present invention.

  As shown in FIGS. 2 and 3, the main body 71 has a rectangular outer edge shape as viewed from the vehicle width direction. The main body 71 has an outer edge shape in which the vertical width b in the vertical direction is equal to or greater than the horizontal width a in the vehicle front-rear direction (b ≧ a). In this embodiment, when the outer edge-shaped vehicle front side is 711, the rear side is 712, the upper side is 713, and the lower side is 714, the vertical width b corresponds to the length of the sides 711 and 712, The width a corresponds to the length of the sides 713 and 714. Therefore, the length b of the side 711 (712) is always longer than the length a of the side 713 (714).

  As shown in FIGS. 1 and 3, the extending portion 72 is a portion extending from the central portion of the upper surface of the main body portion 71 in the vehicle width direction toward the vehicle rear and upward. In other words, the extending portion 72 is a portion in which a part of the chamber member 7 in the vehicle width direction extends to the vehicle rear side and the bumper reinforcement upper surface 4b from the bumper reinforcement front surface 4a. The internal space of the extending portion 72 communicates with the internal space of the main body portion 71 and forms a part of the chamber space 7a. As shown in FIG. 1, the extending portion 72 is provided at a central portion between the side members 5 and 5 in the vehicle width direction.

  A projecting portion 72a protruding in a columnar shape is formed at a rear portion of the extending portion 72, and an insertion port 72b opening upward is formed at the approximate center of the projecting portion 72a. The insertion port 72b is located above the bumper reinforcement upper surface 4b. In addition, when the insertion part 72b is formed in the extending part 72 with a drill etc., the convex part 72a has the effect which prevents that the position of a drill becomes uncertain because a target surface is distorted.

  The special-shaped chamber member 7 is formed by blow molding. The chamber member 7 of the present embodiment can be more easily manufactured by blow molding using, for example, LDPE (low density polyethylene) as a raw material. Note that, in the case where the absorber is not mounted as in the present embodiment, the chamber member 7 may have two actions of shock absorption and pressure transmission in the vehicle bumper 2 (also used as an absorber).

  The pressure sensor 8 is a sensor device capable of detecting a gas pressure, and is configured to be attached to the chamber member 7 so as to detect a pressure change in the chamber space 7a. Specifically, the pressure sensor 8 includes a sensor main body 81 and a pressure introduction pipe 82. The sensor main body 81 is a part that is outside the chamber member 7 and accommodates a substrate or the like provided with a sensor element for pressure detection. The sensor main body 81 outputs a signal proportional to the pressure, and transmits a signal to the pedestrian protection apparatus ECU10 via the signal line 10a.

  The pressure introducing pipe 82 is a substantially cylindrical pipe that introduces the pressure of the chamber space 7 a into the sensor main body 81, and extends downward from the sensor main body 81. The pressure introducing pipe 82 is inserted into an insertion port 72 b provided in the extending portion 72 of the chamber member 7. That is, the pressure introducing pipe 82 is inserted downward, and the inlet for introducing pressure faces downward. A slight gap is formed between the inner periphery of the insertion port 72b and the outer periphery of the pressure introducing pipe 82, and this gap acts as a breathing hole. Therefore, in a normal state where no collision occurs, the chamber The atmospheric pressure in the space 7a is kept the same (atmospheric pressure) as the outside air.

  Here, in the present embodiment, the pressure sensor 8 is fixed to the bumper reinforcement upper surface 4b via the bracket 9 on the vehicle rear side from the bumper reinforcement front surface 4a. The bracket 9 is formed in a bridge shape. The bracket 9 has a structure in which the sensor main body 81 is fixed to the upper surface of the bracket 9 while being fixed to the bumper reinforcement upper surface 4 b so as to straddle the extending portion 72.

  The pedestrian protection device ECU 10 is an electronic control device for performing start-up control of a pedestrian protection device (not shown) (for example, a known pedestrian protection airbag or hood flip-up device), and is output from the pressure sensor 8. Signal is input via the transmission line 10a. The pedestrian protection device ECU 10 executes a process for determining whether or not a pedestrian (that is, a human body) has collided with the vehicle bumper 2 based on the pressure detection result in the pressure sensor 8. In addition to the pressure detection result in the pressure sensor 8, a vehicle speed detection result from a vehicle speed sensor (not shown) is input to the pedestrian protection device ECU 10, and a pedestrian collision is determined based on the pressure detection result and the vehicle speed detection result. It is preferable to configure as described above.

  Here, the pressure change in the chamber space 7a immediately after the collision will be described. As shown in FIG. 4, in the outer edge shape of the main body 71, the moment shown by the arrow is applied to the corner immediately after the collision, both the front and rear sides 711 and 712 are bent inward, and the upper and lower sides 713 and 714 are outward. Deforms into a bent shape.

Here, assuming that the amount of deflection in the vehicle front-rear direction immediately after the collision is δ _x and the amount of deflection in the vertical direction is δ _y , in the outer edge shape, the area where the chamber deformation amount becomes small immediately after the collision is very small is expressed approximately 2bδ _x, larger area can be expressed approximately 2aδ _y. Then, by satisfying 2bδ _x ≧ 2aδ _y, are prevented from the area of the outer edge increased immediately after the collision. That is, an increase in the volume of the chamber space 7a can be prevented.

Here, the amount of deflection is proportional to the square of the length of each side. Therefore, the conditional expression is b ³ ≧ a ³ and b ≧ a. In the present embodiment, the outer edge shape area satisfies the condition (b ≧ a) that does not increase immediately after the collision, and the volume of the chamber space 7a does not increase immediately after the collision. That is, even if the chamber member 7 is deformed immediately after the collision, the pressure change in the chamber space 7a is always on the positive side.

  In the present embodiment, as shown in FIG. 5, the pressure change becomes a positive side immediately after the collision, and the threshold value can be set to a large value with a margin. That is, separation from noise or the like can be executed reliably, and erroneous determination can be prevented. On the other hand, when the volume increases immediately after the collision, as shown in FIG. 6, the pressure change becomes negative immediately after the collision, the amount of pressure change to the positive side decreases, and the threshold value must be reduced. The illustrated ON requirement indicates an example in the case of a collision with a requirement that is ON (collision target), and the OFF requirement indicates an example in the case of a collision with a requirement that is OFF (collision target). Yes.

  Thus, in this embodiment, it is possible to prevent the pressure in the chamber space 7a from being reduced immediately after a collision, and improve the collision detection accuracy. As shown in FIG. 3, the length of the upper side 713 of the outer edge shape is substantially reduced in the portion of the chamber member 7 where the extending portion 72 is provided. Also by this, b ≧ a is satisfied, and furthermore, since the length of the upper side 713 is small, the area (increase amount) that swells upward is reduced, which is more effective.

  Other effects will also be described. The pressure sensor 8 is disposed on the vehicle rear side with respect to the bumper reinforcement front surface 4a and on the upper side with respect to the upper surface 4b. Thereby, the attachment work of the pressure sensor 8 can be carried out in a relatively free space without working in a narrow work area in the bumper reinforcement 4. That is, the workability of the mounting work is improved.

  In addition, since the pressure sensor 8 is connected to the extended portion 72 extending from the main body portion 71 of the chamber member 7 to the vehicle rear side, the stroke of the main body portion 71 is not reduced, and the chamber A sufficient stroke (width in the vehicle longitudinal direction) can be ensured for the member 7. Accordingly, even when the vehicle has a small front space or a vehicle with a small stroke of the absorber, high collision detection accuracy can be exhibited.

<Second embodiment>
A vehicle collision detection apparatus according to a second embodiment will be described with reference to FIGS. FIG. 7 is a diagram corresponding to FIG. 2 in the second embodiment. FIG. 8 is a diagram corresponding to FIG. 4 in the second embodiment. The second embodiment is a case where the absorber 6 in the first embodiment is arranged. Accordingly, components having the same configuration as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 7, the absorber 6 is disposed on the lower surface side of the chamber member 7. The absorber 6 is a foamed resin member that extends in the vehicle width direction and is attached to the lower side of the front surface 4 a of the bumper reinforcement 4 within the bumper cover 3, and exhibits an impact absorbing action in the vehicle bumper 2.

  The chamber member 7 (main body 71) has a rectangular outer edge shape as viewed from the vehicle width direction. In this outer edge shape, when the vertical width in the vertical direction is b and the horizontal width in the vehicle front-rear direction is a. , So that Formula (1) is established.

As shown in FIG. 8, in the second embodiment, immediately after the collision, the front and rear sides 711 and 712 are bent inward, the upper side 713 is bent outward, and the lower side 714 is restrained by the absorber 6 and almost outside. It will be in a state not to bend. Here, in the outer edge, small area immediately after the collision is about 2Bideruta _x, and the larger the area is approximately A-delta _y except deflection of the lower side 714. By satisfying 2bδ _x ≧ aδ _y , the area of the outer edge shape does not increase immediately after the collision, and as a result, an increase in the volume of the chamber space is prevented. Here, since the amount of deflection is proportional to the square of the length of each side, the conditional expression is 2b ³ ≧ a ³ , which is expression (1). This is the same even when the absorber 6 is arranged on the upper surface side of the chamber member 7.

  As described above, in the second embodiment, the condition that the area of the outer edge shape does not increase immediately after the collision (formula (1)) is satisfied, and the volume of the chamber space 7a does not increase immediately after the collision. That is, even if the chamber member 7 is deformed immediately after the collision, the pressure change in the chamber space 7a is always on the positive side. Therefore, the same effect as the first embodiment can be obtained. In addition, also when the absorber 6 exists in the upper surface side of the chamber member 7, the same effect can be acquired by setting it as the said structure.

  In the first embodiment and the second embodiment, the outer edge shape of the chamber member 7 may have a somewhat tapered shape, or may have a curved corner. For example, as shown in FIG. 9, when the upper side 713 is slightly inclined so as to be higher toward the rear (the upper surface of the chamber member 7 is tapered), the length of the front side 711 is a vertical width b and the length of the lower side 714 is The above effect can be obtained by forming the chamber member 7 so that the width a is equal to b ≧ a (when the absorber 6 is present, the expression (1)). Alternatively, the average length of the front side 711 and the rear side 712 may be the vertical width b. In other words, the term “substantially rectangular” in the present invention basically means a rectangle and a square, and further, a side where the side of the rectangle is slightly tilted, a case where the corner of the rectangle is curved instead of the pin angle, Including meaning.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

It is a top view which shows typically the collision detection apparatus 1 for vehicles of 1st embodiment. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is a figure which shows the outer edge of the chamber member 7 just after the collision in FIG. It is a figure which shows the relationship between the pressure change in 1st embodiment, and time. It is a figure which shows the relationship between the pressure change and time when a swelling is large. It is a figure equivalent to FIG. 2 in 2nd embodiment. It is a figure equivalent to FIG. 4 in 2nd embodiment. It is a figure which shows an example of an outer edge shape.

Explanation of symbols

1: vehicle collision detection device, 2: vehicle bumper,
4: bumper reinforcement, 4a: front surface, 4b: upper surface 7: chamber member, 71: main body portion, 72: extension portion, 72a: convex portion, 72b: insertion port,
7a: chamber space,
8: Pressure sensor, 81: Sensor body, 82: Pressure introducing pipe,
9: Bracket, 10: Pedestrian protection device ECU

Claims (3)

A chamber member disposed in front of the bumper reinforcement in the vehicle bumper and having a chamber space formed therein, and a pressure sensor for detecting the pressure in the chamber space, the detection result of the pressure sensor In a vehicle collision detection device configured to detect a collision with the vehicle bumper based on:
The chamber member has a substantially rectangular outer edge shape in a cross section viewed from the vehicle width direction, and in the outer edge shape, the vertical width in the vertical direction is equal to or greater than the horizontal width in the vehicle front-rear direction. Detection device. A chamber member disposed in front of a bumper reinforcement in a vehicle bumper and having a chamber space formed therein, an absorber disposed on an upper surface side or a lower surface side of the chamber member, and a pressure in the chamber space A collision detection device for a vehicle comprising: a pressure sensor for detection; and configured to detect a collision with the vehicle bumper based on a detection result of the pressure sensor.
The chamber member has a substantially rectangular outer edge shape in a cross section viewed from the vehicle width direction, and in the outer edge shape, the vertical width in the vertical direction is b, and the horizontal width in the vehicle front-rear direction is a.

A vehicle collision detection device characterized by the above.   The vehicle collision detection device according to claim 1, wherein the chamber member is integrally molded by blow molding using a resin material.

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