JP2007263601A - Abnormality detection method for collision detecting means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for detecting abnormality in a collision detecting means capable of detecting collision of a pedestrian with a bumper of a vehicle. <P>SOLUTION: This abnormality detection method for the collision detecting means of the present invention has a reverse plate, a chamber member for partitioning a chamber space, and a pressure sensor, and detects the abnormality of the collision detecting means for detecting the collision, based on pressure fluctuation in the chamber space. In the method, pressure of the chamber space before the collision is measured to compare the measured pressure with a preset pressure threshold value, and the abnormality is determined when the measured pressure is the preset pressure threshold value or more. The abnormality detection method for the collision detecting means of the present invention can detect precisely a collision object when the collision object collides with the collision detecting means, by confirming that a stroke capable of deforming a chamber member is secured in the collision occurred hereafter, based on the pressure of the chamber space, before the detected collision occurs. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a failure detection method for a collision detection unit that detects a failure of a collision detection unit that is attached to a vehicle and detects a collision of a colliding object with the vehicle.

  In recent years, safety has been improved in vehicles in the event of an accident. Regarding vehicle safety, not only is it necessary to ensure the safety of the vehicle occupant in the event of an accident, but it has also been required that the pedestrian not be fatally damaged when the pedestrian collides with the vehicle.

  As a means for protecting a pedestrian that has collided with a vehicle, a method of reducing the injury value (impact received by the pedestrian) received by a pedestrian who collided with the vehicle and fell into the hood has been considered. By reducing the impact of pedestrians, pedestrians are prevented from receiving fatal damage. In such a protective device, it is important to detect a collision with a vehicle such as a pedestrian.

  For example, Patent Document 1 discloses a means for detecting a collision with a vehicle.

  In Patent Document 1, a front sensor of a vehicle in which the front sensor is formed as a contact sensor, the front sensor has at least one cavity, and the cavity is in the cavity. A vehicle front sensor is disclosed in which each sensor element is provided and the front sensor detects a collision depending on the deformation of the cavity by the sensor element. Yes.

  However, Patent Document 1 discloses that another sensor that can detect a pedestrian collision is assembled. That is, the vehicle front sensor disclosed in Patent Document 1 is not suitable for detecting a pedestrian collision.

  The application of the detection method described in Patent Document 1 to a vehicle bumper for the purpose of detecting the collision of a pedestrian against the vehicle bumper has been considered. As a result, the collision detection means having the configuration shown in FIGS. It was. As shown in FIGS. 1 and 2, this structure has a chamber space 20 (airtight) sealed between a bumper reinforcement 1 fixed to the side member Fm and a bumper cover 4 that forms the outer peripheral surface of the bumper of the vehicle. A chamber member 2 that divides the space (a space corresponding to the cavity of Patent Document 1) is disposed, and a pedestrian collision is detected from pressure fluctuations in the space 20 measured by the pressure sensor 3.

  The collision detection means having such a structure detects a collision based on the pressure fluctuation in the chamber space generated by the deformation (plastic deformation) of the chamber member, but the collision impact by the collision object is small (for example, In the case where the deformation amount of the chamber member due to the collision object is small), the change in the shape generated in the chamber member is eliminated by the elasticity of the chamber member itself (the pressure in the chamber space returns to the pressure before the collision).

  However, when the impact of the collision is large, the shape restoration by the chamber member itself is insufficient, and the deformation remains in the chamber member after the collision. Further, when a collision object collides with the deformation remaining in the chamber member, a sufficient amount of deformation of the chamber member due to the collision cannot be secured, and an error occurs in the detection of the collision.

  More specifically, it is assumed that the collision object collides with the chamber member (the pressure P0 of the chamber space) in which no deformation has occurred (first light collision). By this collision, the pressure in the chamber space increases to P1, and then the pressure decreases. This decrease in pressure occurs due to the elasticity of the material of the chamber member itself. If the collision is a slight collision, the shape of the chamber member is completely restored, and the pressure in the chamber space is reduced to the pressure P0 before the collision. In such a state, even if the colliding object collides again, it is possible to detect the colliding object without causing a problem.

  When the impact caused by the collision of the colliding object in the first light collision is large, the pressure in the chamber space increases to P1 and then decreases, and the pressure in the chamber space decreases to P2 (P0 <P2 <P1). The pressure in the chamber space is maintained as P2 as the residual pressure. That is, the deformation caused by the collision is not completely recovered in the chamber member.

  Assume that the colliding object collided again (second light collision) in such a state. When the second light collision occurs, the pressure in the chamber space increases from P2 to P3, and then the pressure decreases. When the second light collision is also a minor collision, as shown in FIG. 4, even if pressure remains after the first collision light collision, a change in pressure in the chamber space can be detected.

However, when the second light collision is a relatively large impact (a collision in which the pressure in the chamber space changes greatly), the pressure of the first light collision remains (deformation remains in the chamber member). Therefore, as shown in FIG. 5, the change in pressure due to the second light collision is saturated at P4 (the bottom of the chamber member is deformed and the deformation stroke cannot be secured). When the pressure is saturated, the pressure value measured when the pressure is saturated becomes constant, and the peak of the pressure that should be originally measured cannot be measured. That is, there is a problem that the accuracy of detecting a collision object is lowered.
JP 2005-538881 A

  This invention is made | formed in view of the said actual condition, and makes it a subject to provide the method of detecting the abnormality of the collision detection means which can detect the collision of the pedestrian to the bumper of a vehicle.

  In order to solve the above-mentioned problems, the present inventors have studied the collision detection means that can be assembled to the bumper of the vehicle, and as a result, have reached the present invention.

  An abnormality detection method for a first collision detection means of the present invention includes a back plate fixed to a side member of a vehicle, a chamber member that defines a sealed chamber space disposed in front of the back plate, A pressure sensor for detecting pressure, and detecting an abnormality of a collision detection means for detecting a collision from a fluctuation in pressure in the chamber space, wherein the pressure in the chamber space before the collision is measured and measured. The measured pressure is compared with a preset pressure threshold value, and when the measured pressure is equal to or higher than the pressure threshold value, it is determined that there is an abnormality.

  An abnormality detection method for a second collision detection means of the present invention includes a back plate fixed to a side member of a vehicle, a chamber member that defines a sealed chamber space disposed in front of the back plate, A pressure sensor for detecting pressure, and detecting an abnormality of a collision detection means for detecting a collision from a fluctuation in pressure in the chamber space, the pressure in the chamber space before the collision and a sufficient time after the collision. When the pressure in the chamber space is measured and the pressure in the chamber space changed due to the collision is compared with a preset pressure threshold value, an abnormality occurs when the changed pressure is greater than or equal to the pressure threshold value. It is characterized by determining.

  According to the abnormality detection method of the collision detection means of the present invention, before the detected collision occurs, it is confirmed from the pressure in the chamber space that a stroke that can deform the chamber member in the subsequent collision is secured. If no abnormality is detected by this abnormality detection method, the collision detection means can detect the collision object with high accuracy when the collision object collides.

(First abnormality detection method)
An abnormality detection method for a first collision detection means according to the present invention includes a back plate, a chamber member that defines a chamber space, and a pressure sensor, and detects collision from fluctuations in pressure in the chamber space. A method for detecting an abnormality of the means, wherein the pressure in the chamber space before the collision is measured, the measured pressure is compared with a preset pressure threshold, and the measured pressure is detected by the pressure threshold. It is determined as abnormal when the value is equal to or greater than the value. If the pressure in the chamber space is compared with the pressure threshold, and the pressure in the chamber space is less than the pressure threshold, even if a collision with a large impact occurs and the chamber member is deformed, the deformation stroke can be secured. The chamber space pressure does not saturate. Comparing the pressure in the chamber space with the pressure threshold, if the pressure in the chamber space is equal to or greater than the pressure threshold, the pressure in the chamber space will saturate when a large collision occurs, and the collision can be detected. It can be judged that it will disappear. Specifically, the amount of deformation of the chamber member is substantially constant, and if the deformation remains in the chamber member, the amount of deformation that the chamber member can be deformed at the time of collision decreases, and the pressure in the chamber space is saturated, Collisions cannot be detected accurately. From this, the abnormality detection method of the present invention detects an abnormality of the collision detection means.

  The pressure in the chamber space before the collision is preferably the pressure in the chamber space when a sufficient time has elapsed since the previous collision. If enough time has passed since the previous time, even if there has been a change in the shape of the chamber member before that (due to a collision), the change in the shape of the chamber member will end and the pressure in the chamber space will become constant. ing. That is, it shows a state in which the pressure in the chamber space is not changed. Specifically, even if a collision occurs and the chamber member is deformed, the shape of the chamber member returns to the shape of the chamber member before the collision or the pressure due to the impact at the time of the collision remains due to its own elasticity. Then, after the collision object collides with the collision detection means, the chamber member pressure of the collision detection means is determined to be abnormal before the pressure in the chamber space when a sufficient time has passed is compared with the pressure threshold value. Even if there is a residual deformation caused by the collision, it can be determined that the deformation does not affect the collision detection, and the collision can be detected.

  In the abnormality detection method of the collision detection means of the present invention, the pressure threshold value cannot be determined unconditionally because the collision to be detected is different, such as the shape and material of the chamber member and the assembly position on the vehicle.

The collision detection means for detecting an abnormality of the present invention includes a back plate, a chamber member, and a pressure sensor, and the configuration thereof is particularly limited as long as it is a collision detection means that detects a collision from a change in pressure in the chamber space. Not something
A collision detection means for detecting an abnormality according to the present invention includes a back plate fixed to a side member of a vehicle, a chamber member disposed in front of the back plate and defining a sealed chamber space, and a pressure in the chamber space. And a pressure sensor for detecting the collision from the fluctuation of the pressure in the chamber space. That is, the collision detection means of the present invention is attached to a bumper formed by a side member of the vehicle, and detects a collision of a pedestrian or the like with the bumper of the vehicle.

  The back plate is a member fixed to the side member of the vehicle, whereby the collision detection means is assembled to the bumper of the vehicle and can detect a collision with the bumper of the vehicle. The back plate may be configured to be fixed to a bumper reinforcement or a crash box fixed to the side member, but is more preferably fixed directly to the side member of the vehicle. More preferably, the back plate is made of bumper reinforcement. Since the back plate is bumper reinforcement, it is not necessary to newly add a member to be the back plate, and an increase in cost can be suppressed.

  The chamber member is a member that defines a sealed chamber space. The chamber member is disposed in front of the back plate (not the front of the vehicle but the surface direction in which the collision object collides). By disposing the chamber member in front of the back plate, the chamber member is assembled to the bumper of the vehicle, and a collision with the bumper of the vehicle can be detected.

  When the collision object collides with the vehicle, the collision detection unit presses the chamber member and fluctuates (increases) the pressure in the chamber space. And the pressure fluctuation of the chamber space at the time of this collision is measured with a pressure sensor. A collision is detected from the measurement result of the pressure sensor.

  The collision detection means is assembled to a vehicle bumper. Usually, the bumper of a vehicle forms the outer peripheral surface of the vehicle. That is, the collision detection means of the present invention preferably has a bumper cover that forms the outer peripheral surface of the vehicle.

  When the collision detection means has a bumper cover, the bumper cover only needs to be positioned in front of the chamber member (not the front of the vehicle but the surface direction in which the collision object collides). That is, the front surface of the chamber member and the bumper cover may be arranged with a gap therebetween or may be arranged in a state where they are in contact with each other. Here, when the chamber member and the bumper cover are spaced apart from each other, the deformation of the bumper cover in a state in which the colliding object does not collide can be restricted. Therefore, it is preferable to dispose the filling member between the two.

  In the collision detection means, it is preferable that the chamber member is disposed along the axial direction of the vehicle, and a pressing member formed to be harder than the chamber member is disposed in front of the chamber member. In this configuration, the pressing member is the above filling member. Because the pressing member is made of a material harder than the chamber member, when the collision object collides, the pressing member absorbs the impact of the collision at least before pressing the chamber member (stress for deforming the chamber member). Is suppressed. That is, the collision object deforms the chamber member via the pressing member, and increases the pressure in the chamber space. Examples of the material constituting the pressing member include a resin structure and a foamed resin molded body.

  The chamber member is preferably disposed on the surface of the back plate, and a surface facing the back plate is formed along the outer peripheral surface of the vehicle. With such a configuration, the chamber member has a surface (a surface along the bumper cover) that substantially coincides with the bumper cover, and deformation of the bumper cover in a state where the collision object does not collide can be restricted.

  When the surface facing the back plate of the chamber member is formed along the outer peripheral surface of the vehicle, the facing surface of the chamber member and the back plate may be spaced apart or both may be in contact with each other. Good. Since the deformation of the bumper cover in a state where the collision object does not collide can be restricted when the chamber member and the back plate are arranged at an interval, it is preferable that a filling member is arranged between the two.

  A pressing member formed to be harder than the chamber member is disposed on the surface of the back plate, and the chamber member is disposed on the surface of the pressing member with the axial direction curved along the outer peripheral surface of the vehicle. It is preferable that the cross-sectional shape in a cross section perpendicular to the direction has a substantially columnar shape.

  The shape of the chamber member is not particularly limited. For example, the shape may be a shape in which the shape in the cross section perpendicular to the axial direction is constant or a shape in which the cross sectional shape changes. Further, when the chamber member has a substantially columnar shape, the axial direction may be either linear or curved and extended.

  The collision detection means is effective in detecting a collision object with respect to the bumper of the vehicle to be assembled, but it is preferable to detect a pedestrian collision with the vehicle bumper.

  The collision detection means preferably has a calculation means for determining a collision by obtaining a pressure variation in the chamber space from a detection signal from the pressure sensor. By having the calculation means, not only can collisions be determined, but also collision objects can be determined from pressure fluctuations during the collision. And when it determines with it being a pedestrian, an operation signal can be emitted to the pedestrian protection means provided outside the vehicle.

  The abnormality detection method for the collision detection means of the present invention preferably has a calculation means. This calculation means may be either a calculation means of the collision detection means or a calculation means provided separately. More preferably, the calculation means for comparing the pressure in the chamber space measured with the abnormality detection method of the present invention with the pressure threshold value is a calculation means of the collision detection means.

(Second abnormality detection method)
An abnormality detection method for a first collision detection means according to the present invention includes a back plate, a chamber member that defines a chamber space, and a pressure sensor, and detects collision from fluctuations in pressure in the chamber space. This is a method for detecting the abnormality of the means, and measures the pressure of the chamber space before the collision and the pressure of the chamber space after a sufficient time has passed after the collision, and the pressure of the chamber space changed by the collision is set in advance. The pressure threshold value is compared, and when the fluctuating pressure is equal to or higher than the pressure threshold value, it is determined as abnormal. If the pressure change in the chamber space due to the collision is less than the pressure threshold by comparing the pressure in the chamber space changed by the collision and the pressure threshold value, a collision with a large impact occurs and the chamber member is deformed. However, the deformation stroke can be secured and the pressure in the chamber space is not saturated. Comparing the pressure in the chamber space changed by the collision and the pressure threshold, and if the amount of pressure change in the chamber space is equal to or greater than the pressure threshold, the pressure in the chamber space will saturate when a large collision occurs. Thus, it can be determined that the collision cannot be detected. Specifically, the amount of deformation of the chamber member is substantially constant, and if the deformation remains in the chamber member, the amount of deformation that the chamber member can be deformed at the time of collision decreases, and the pressure in the chamber space is saturated, Collisions cannot be detected accurately. From this, the abnormality detection method of the present invention detects an abnormality of the collision detection means.

  The collision detection means of the present invention compares not the pressure in the chamber space but the amount of change in pressure before and after the collision with the pressure threshold value. The pressure in the chamber space varies depending on the temperature outside the chamber space. For this reason, by comparing the amount of change in the pressure in the chamber space with the pressure threshold value, errors due to conditions such as the external temperature can be eliminated, and this is an abnormality detection method with better detection accuracy. .

  The pressure in the chamber space before the collision is preferably the pressure in the chamber space when a sufficient time has elapsed since the previous collision. If enough time has passed since the previous time, even if there has been a change in the shape of the chamber member before that (due to a collision), the change in the shape of the chamber member will end and the pressure in the chamber space will become constant. ing. That is, it shows a state in which the pressure in the chamber space is not changed. Specifically, even when a collision occurs and the chamber member is deformed, the shape of the chamber member returns to the shape of the chamber member before the collision or a residual stress due to an impact at the time of the collision remains due to its own elasticity. Then, after the collision object collides with the collision detection means, the chamber member pressure of the collision detection means is determined to be abnormal before the pressure in the chamber space when a sufficient time has passed is compared with the pressure threshold value. Even if there is a residual deformation caused by the collision, it can be determined that the deformation does not affect the collision detection, and the collision can be detected.

  In the abnormality detection method of the collision detection means of the present invention, the pressure threshold value cannot be determined unconditionally because the collision to be detected is different, such as the shape and material of the chamber member and the assembly position on the vehicle.

The collision detection means for detecting an abnormality of the present invention includes a back plate, a chamber member, and a pressure sensor, and the configuration is particularly limited as long as it is a collision detection means that detects a collision from a change in pressure in the chamber space. not,
A collision detection means for detecting an abnormality according to the present invention includes a back plate fixed to a side member of a vehicle, a chamber member disposed in front of the back plate and defining a sealed chamber space, and a pressure in the chamber space. And a pressure sensor for detecting the collision from the fluctuation of the pressure in the chamber space. That is, the collision detection means of the present invention is attached to a bumper formed by a side member of the vehicle, and detects a collision of a pedestrian or the like with the bumper of the vehicle.

  The back plate is a member fixed to the side member of the vehicle, whereby the collision detection means is assembled to the bumper of the vehicle and can detect a collision with the bumper of the vehicle. The back plate may be configured to be fixed to a bumper reinforcement or a crash box fixed to the side member, but is more preferably fixed directly to the side member of the vehicle. More preferably, the back plate is made of bumper reinforcement. Since the back plate is bumper reinforcement, it is not necessary to newly add a member to be the back plate, and an increase in cost can be suppressed.

  The chamber member is a member that defines a sealed chamber space. The chamber member is disposed in front of the back plate (not the front of the vehicle but the surface direction in which the collision object collides). By disposing the chamber member in front of the back plate, the chamber member is assembled to the bumper of the vehicle, and a collision with the bumper of the vehicle can be detected.

  When the collision object collides with the vehicle, the collision detection unit presses the chamber member and fluctuates (increases) the pressure in the chamber space. And the pressure fluctuation of the chamber space at the time of this collision is measured with a pressure sensor. A collision is detected from the measurement result of the pressure sensor.

  The collision detection means is assembled to a vehicle bumper. Usually, the bumper of a vehicle forms the outer peripheral surface of the vehicle. That is, the collision detection means of the present invention preferably has a bumper cover that forms the outer peripheral surface of the vehicle.

  When the collision detection means has a bumper cover, the bumper cover only needs to be positioned in front of the chamber member (not the front of the vehicle but the surface direction in which the collision object collides). That is, the front surface of the chamber member and the bumper cover may be arranged with a gap therebetween or may be arranged in a state where they are in contact with each other. Here, when the chamber member and the bumper cover are spaced apart from each other, the deformation of the bumper cover in a state in which the colliding object does not collide can be restricted. Therefore, it is preferable to dispose the filling member between the two.

  In the collision detection means, it is preferable that the chamber member is disposed along the axial direction of the vehicle, and a pressing member formed to be harder than the chamber member is disposed in front of the chamber member. In this configuration, the pressing member is the above filling member. Because the pressing member is made of a material harder than the chamber member, when the collision object collides, the pressing member absorbs the impact of the collision at least before pressing the chamber member (stress for deforming the chamber member). Is suppressed. That is, the collision object deforms the chamber member via the pressing member, and increases the pressure in the chamber space. Examples of the material constituting the pressing member include a resin structure and a foamed resin molded body.

  The chamber member is preferably disposed on the surface of the back plate, and a surface facing the back plate is formed along the outer peripheral surface of the vehicle. With such a configuration, the chamber member has a surface (a surface along the bumper cover) that substantially coincides with the bumper cover, and deformation of the bumper cover in a state where the collision object does not collide can be restricted.

  When the surface facing the back plate of the chamber member is formed along the outer peripheral surface of the vehicle, the facing surface of the chamber member and the back plate may be spaced apart or both may be in contact with each other. Good. Since the deformation of the bumper cover in a state where the collision object does not collide can be restricted when the chamber member and the back plate are arranged at an interval, it is preferable that a filling member is arranged between the two.

  A pressing member formed to be harder than the chamber member is disposed on the surface of the back plate, and the chamber member is disposed on the surface of the pressing member with the axial direction curved along the outer peripheral surface of the vehicle. It is preferable that the cross-sectional shape in a cross section perpendicular to the direction has a substantially columnar shape.

  The shape of the chamber member is not particularly limited. For example, the shape may be a shape in which the shape in the cross section perpendicular to the axial direction is constant or a shape in which the cross sectional shape changes. Further, when the chamber member has a substantially columnar shape, the axial direction may be either linear or curved and extended.

  The collision detection means is effective in detecting a collision object with respect to the bumper of the assembled vehicle, but it is preferable to detect a pedestrian collision with the vehicle bumper.

  The collision detection means preferably has a calculation means for determining a collision by obtaining a pressure variation in the chamber space from a detection signal from the pressure sensor. By having the calculation means, not only can collisions be determined, but also collision objects can be determined from pressure fluctuations during the collision. And when it determines with it being a pedestrian, an operation signal can be emitted to the pedestrian protection means provided outside the vehicle.

  The abnormality detection method for the collision detection means of the present invention preferably has a calculation means. This calculation means may be either a calculation means of the collision detection means or a calculation means provided separately. More preferably, the calculation means for comparing the pressure in the chamber space measured with the abnormality detection method of the present invention with the pressure threshold value is a calculation means of the collision detection means.

  Hereinafter, the present invention will be described using examples.

  First, a collision detection means was manufactured.

(Collision detection means)
The collision detection means of the present embodiment includes a bumper reinforcement 1, a chamber member 2, a pressure sensor 3, and a calculation means (not shown). The structure of the collision detection means of the present embodiment is shown in FIGS. 1 is a top view of the collision detection means of the present embodiment, and FIG. 2 is a view showing a cross section taken along the line II of FIG.

  The bumper reinforcement 1 is a substantially strip-shaped metal plate whose surface faces the front of the vehicle. The bumper reinforcement 1 is fixed to the pair of front side members Fm in a state where the extending direction of the band extends along the width direction of the vehicle. The front side member Fm of the vehicle to which the bumper reinforcement 1 is fixed is a pair of members protruding forward of the engine room of the vehicle.

  The chamber member 2 is a substantially columnar member having a square cross section with a chamber space 20 defined therein. The columnar axial direction was fixed and arranged on the surface of the bumper reinforcement 1 with the bumpy reinforcement 1 extending along the extending direction.

  The pressure sensor 3 is a sensor for measuring the pressure of the chamber space 20 of the chamber member 2 and is assembled to the chamber member 2.

  The calculation means is connected to the pressure sensor 3 and calculates the pressure in the chamber space 20 from the detection signal of the pressure sensor 3 and determines a collision from the calculated pressure. The calculation means may be a calculation means mounted in advance on the vehicle. Preferably, it is an arithmetic means of an occupant protection device or a pedestrian protection device.

  The collision detection by the collision detection means of the present embodiment will be described below.

  As shown in FIG. 1, the bumper of the vehicle in which the collision detection means of this embodiment is assembled forms the outer surface of the bumper of the vehicle with the bumper cover 4 covering the chamber member 2.

  When a collision object collides with the bumper of the vehicle, the collision object presses the bumper of the vehicle. The collision object presses the chamber member 2 via the bumper cover 4 of the bumper of the vehicle, and the chamber member 2 is deformed.

  Due to the deformation of the chamber member 2, the pressure inside the chamber space 20 rises, the pressure sensor 3 measures the change in pressure, and the calculation means detects the change in pressure. And a calculating means determines with the collision object having collided with the vehicle from the change (rise) of the pressure. Further, the calculation means can determine whether the collision object is a human body such as a pedestrian or the like or a hard structure such as another vehicle from the degree of change (change ratio) of the pressure. At this time, it is preferable that vehicle speed data is also input to the calculation means.

Example 1
Below, the 1st abnormality detection method of the collision detection means of a present Example is demonstrated.

First, to measure the pressure P _A in the previous chamber space 20 to collide colliding object to the bumper of the vehicle. Measurements of the pressure P _A, if before the collision may at any time, for example, when the ignition of the vehicle is turned on, a sufficient amount of time has elapsed since the are and the collision after colliding object collides with the bumper of the vehicle It can be when the change of the shape of the chamber member 2 is finished (when the change of the pressure in the chamber space 20 is finished).

Then, comparing the pressure threshold P _TH which is previously set and measured pressure P _A. When the pressure P _A is smaller than the pressure threshold value P _TH , the collision detection means determines that there is no abnormality. Further, when the pressure P _A is larger than the pressure threshold value P _TH , the pressure in the chamber space is saturated when the collision object collides and the pressure in the chamber space 20 changes. That is, since it becomes impossible to detect a collision with high accuracy, it is determined that the collision detection means is abnormal. And it is preferable to notify a driver | operator etc. when abnormality of a collision detection means is detected.

Detection method of this embodiment is a detection method for detecting an abnormality of the collision detection means by comparing the pressure P _A and the pressure threshold value P _TH of the collision before the chamber space 20. That is, even if a collision object collides with the bumper of the vehicle in the past and the chamber member 2 is deformed and the shape change remains, after the deformation (the time has elapsed since the collision, the shape of the chamber member 2 is changed). the pressure in the chamber space 20 when) no longer changed (corresponding to the measured pressure P _a) can be performed detecting the collision if lower than the pressure threshold P _TH.

  By detecting the abnormality of the collision determination unit as described above, the collision detection unit of this embodiment can detect the collision object with high accuracy when the collision object collides.

(Example 2)
Below, the 2nd abnormality detection method of the collision detection means of a present Example is demonstrated.

First, the pressure P _C of the chamber space 20 before the collision object collides with the bumper of the vehicle is measured. The pressure P _C may be measured at any time before the collision. For example, the pressure P _C may be measured every predetermined time from when the vehicle ignition is turned on to obtain the newest pressure value.

  Assume that a collision object collides with the bumper of this vehicle. As shown in FIG. 4, in a normal vehicle collision, the pressure in the chamber space 20 changes in a short time of about 100 ms.

Then, the pressure P _D of a collision when a change in shape of the chamber member 2 has elapsed 100ms about time has expired from (when a change in pressure in chamber space 20 is completed) to the chamber member 2 of the chamber space 20 taking measurement.

Then, the pressure P _C of the front collision pressure P _D after the measured collision, obtains the variation amount P _E of the pressure caused by the collision. The pressure change amount P _E is compared with a preset pressure threshold value P _TH . When the pressure P _E is smaller than the pressure threshold value P _TH , the collision detection means determines that there is no abnormality. When the pressure P _E is larger than the pressure threshold value P _TH , the pressure in the chamber space is saturated when the collision object collides and the pressure in the chamber space 20 changes. That is, since it becomes impossible to detect a collision with high accuracy, it is determined that the collision detection means is abnormal. And it is preferable to notify a driver | operator etc. when abnormality of a collision detection means is detected.

  The abnormality detection method of the collision detection means of this embodiment detects an abnormality from the amount of change in the pressure of the chamber space 20 caused by the collision. That is, the pressure in the chamber space 20 of the chamber member 2 changes depending on conditions such as the outside air temperature, but the pressure in the chamber space 20 due to this external factor is obtained by obtaining the amount of change in pressure as in this embodiment. Measurement error will not occur. For this reason, the collision detection means of the present embodiment can detect the abnormality of the collision detection means with higher accuracy.

  By detecting an abnormality in the collision determination unit as described above, the collision detection unit can detect the collision object with high accuracy when the collision object collides.

It is the figure which showed the structure of the collision detection means of an Example. It is sectional drawing which showed the structure of the collision detection means of an Example. It is the figure which showed an example of the pressure change of the chamber space when a collision object collides. It is the figure which showed the pressure change of the chamber space when a collision object collides. It is the figure which showed the pressure change of the chamber space when a collision object collides.

Explanation of symbols

1: Bumper reinforcement 2: Chamber member 20: Chamber space 3: Pressure sensor 4: Bumper cover

Claims (3)

A back plate fixed to a side member of the vehicle;
A chamber member defining a sealed chamber space disposed in front of the back plate;
A pressure sensor for detecting the pressure in the chamber space;
A method of detecting an abnormality of a collision detection means for detecting a collision from a change in pressure in the chamber space,
The pressure in the chamber space before the collision is measured, and the measured pressure is compared with a preset pressure threshold value. When the measured pressure is equal to or higher than the pressure threshold value, it is determined that there is an abnormality. An abnormality detection method for collision detection means, characterized in that   The method of detecting an abnormality of the collision detection means according to claim 1, wherein the pressure in the chamber space before the collision is a pressure in the chamber space when a sufficient time has elapsed since the previous collision. A back plate fixed to a side member of the vehicle;
A chamber member defining a sealed chamber space disposed in front of the back plate;
A pressure sensor for detecting the pressure in the chamber space;
A method of detecting an abnormality of a collision detection means for detecting a collision from a change in pressure in the chamber space,
Measure the pressure of the chamber space before the collision and the pressure of the chamber space after a sufficient time has elapsed after the collision, and compare the pressure of the chamber space changed by the collision with a preset pressure threshold value. An abnormality detection method for collision detection means, wherein the abnormality is determined when the changed pressure is equal to or greater than the pressure threshold value.

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