JP7037983B2 - Collision detector - Google Patents

Description

The present invention relates to a collision detection device, and more particularly to a collision detection device arranged on the front side of a bumper beam of a vehicle.

Conventionally, when a collision body collides with the front part of a vehicle, a collision detection device that detects the collision has been used. For example, in a collision detection device, a sensor tube is housed in a recess of a shock absorbing portion arranged on the front side of a bumper beam of a vehicle, and the sensor tube is pressed in response to the impact of a collision to cause a pressure wave in the sensor tube. Occurs. By detecting the pressure wave generated in this sensor tube, the collision of the vehicle can be detected. Here, the collision detection device is required to stably detect the collision of the vehicle.

Therefore, as a technique for stably detecting a vehicle collision, for example, Patent Document 1 describes a vehicle bumper provided with a pedestrian collision detection sensor that detects a collision without depending on a change in the hardness of a shock absorbing portion due to temperature. The structure has been proposed. In this vehicle bumper structure, a convex holding portion for holding the sensor tube from below is provided on the rear surface of the shock absorbing portion. Here, since the width of the holding portion in the vehicle front-rear direction is formed to be smaller than the diameter of the sensor tube, the sensor tube comes into contact with the bumper beam before the holding portion. Therefore, the sensor tube is pressed independently of the change in hardness due to the temperature of the shock absorbing portion, and the collision of the vehicle can be stably detected.

Japanese Unexamined Patent Publication No. 2017-7368

However, in the vehicle bumper structure of Patent Document 1, since the deformation of the sensor tube due to pressing is not regulated in the middle, there is a possibility that the impact of the collision cannot be accurately detected if the sensor tube is deformed so as to be completely crushed.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a collision detection device that accurately detects the impact of a vehicle collision.

The collision detection device according to the present invention is arranged so as to extend in the vehicle width direction on the front side of the bumper beam of the vehicle, and has a recess formed on the bumper beam side, which is deformed by the collision of the vehicle to absorb the impact. A shock absorbing portion, a deformation regulating portion arranged in a recess and having an accommodating groove opening on the bumper beam side, and a deformation restricting portion having a tube shape and being formed so as to extend in the vehicle width direction and accommodating in the accommodating groove. A sensor tube that is pressed by deformation of the shock absorbing portion to generate a pressure wave inside and a pressure sensor that is connected to the sensor tube to detect the pressure wave are provided. It is formed shallower than the diameter of the sensor tube and has a higher rigidity than the shock absorbing portion so as to regulate the deformation of the sensor tube.

Here, assuming that the wall thickness of the sensor tube is t, it is preferable that the depth A of the accommodating groove is formed so as to satisfy A> 2t.

Further, assuming that the inner diameter of the sensor tube is d, the width B of the accommodating groove can be formed so as to satisfy B ≧ d · π / 2 + 2t.

Further, assuming that the wall thickness of the sensor tube is t and the inner diameter of the sensor tube is d, the width B of the accommodating groove can be formed so as to satisfy B <d · π / 2 + 2t.

Further, it is preferable that at least one of the shock absorbing portion and the sensor tube is arranged so as to be in contact with the bumper beam.

According to the present invention, the deformation restricting portion has a housing groove formed shallower than the diameter of the sensor tube and has a higher rigidity than the shock absorbing portion so as to regulate the deformation of the sensor tube, so that the impact of a vehicle collision can be accurately detected. It becomes possible to provide a collision detection device for detection.

It is a figure which shows the structure of the airbag apparatus provided with the collision detection apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the collision detection apparatus. It is sectional drawing which shows how the deformation regulation part regulates the deformation of a sensor tube. It is a figure which shows the state that a pressure wave propagates through a sensor tube. It is a figure which shows the state that a pressure wave propagates through a crushed sensor tube. It is sectional drawing which shows the structure of the deformation regulation part in Embodiment 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows the configuration of an airbag device including the collision detection device according to the first embodiment of the present invention. This airbag device has a collision detection device 1, and a calculation unit 2, a deployment control unit 3, and an airbag 4 are sequentially connected to the collision detection device 1.

The collision detection device 1 has a sensor tube 5 and a pair of pressure sensors 6a and 6b, and is arranged inside a bumper face F provided at the front portion of the vehicle.
The sensor tube 5 is arranged so as to extend in the vehicle width direction and has a circular tube shape, and a propagation path communicating from one end to the other end is formed inside. The sensor tube 5 is deformed in response to the impact of the collision body colliding with the vehicle, and the pressure wave generated by the deformation is propagated to one end side and the other end side by the propagation path, respectively.

The pressure sensors 6a and 6b are connected to both ends of the sensor tube 5 and detect a pressure wave propagating in the propagation path of the sensor tube 5, and for example, a sensor using a diaphragm can be used.

The calculation unit 2 calculates the intensity of the pressure wave detected by the pressure sensors 6a and 6b.
The deployment control unit 3 determines whether or not the vehicle has collided with the colliding body based on the intensity of the pressure wave calculated by the calculation unit 2, and controls the deployment of the airbag 4 based on the determination result. That is, when the deployment control unit 3 determines that the vehicle has collided with the colliding body, the deployment control unit 3 injects a deploying gas from an inflator (not shown) to deploy the airbag 4. On the other hand, if the deployment control unit 3 determines that the vehicle has not collided with the colliding body, the deployment control unit 3 does not drive the inflator and the airbag 4 is not deployed.
The airbag 4 is housed under the front hood and is deployed outside the vehicle so as to cover the trailing edge of the front hood by injecting a deploying gas from an inflator (not shown).

Next, the configuration of the collision detection device 1 will be described in detail.
As shown in FIG. 2, the collision detection device 1 has a shock absorbing unit 7 and a deformation regulating unit 8.
The shock absorbing portion 7 absorbs the impact of a collision body colliding with the vehicle, and is formed so as to project from the bumper beam M of the vehicle toward the bumper face F. Further, the shock absorbing portion 7 is arranged so as to extend in the vehicle width direction while being in contact with the front surface of the bumper beam M, and a recess 9 opening to the bumper beam M side is formed on the rear surface facing the bumper beam M. The recess 9 has a size such that the sensor tube 5 can be accommodated. Further, the shock absorbing unit 7 is configured to be deformed in response to an impact applied to the vehicle, and can be made of, for example, a foamed resin.

The deformation regulating portion 8 is arranged so as to extend in the vehicle width direction along the recess 9 of the shock absorbing portion 7, and a housing groove 10 opening on the bumper beam M side is formed. That is, the deformation restricting portion 8 is configured by connecting a bottom plate portion 8a arranged along the bottom surface of the recess 9 and a pair of side plate portions 8b arranged so as to face each other along the side surface of the recess 9. Has been done. Further, the deformation regulating portion 8 is formed so that the housing groove 10 is shallower than the diameter L of the sensor tube 5 so that the rear portion of the sensor tube 5 protrudes to the outside of the housing groove 10. The deformation regulating unit 8 has a higher rigidity than the shock absorbing unit 7 so as to regulate the deformation of the sensor tube 5, and can be made of, for example, a metal or a synthetic resin.

As shown in FIG. 3A, the accommodating groove 10 is formed larger than the sensor tube N in a completely collapsed state. Here, assuming that the wall thickness of the sensor tube 5 is t and the inner diameter of the sensor tube 5 is d, the sensor tube N in a completely crushed state can be represented by a thickness S of 2t and a width W of d · π / 2 + 2t. can. Therefore, the depth A of the accommodating groove 10 is formed so as to satisfy the following equation (1), and the width B of the accommodating groove 10 is formed so as to satisfy the following equation (2).
A> 2t ・ ・ ・ (1)
B ≧ d ・ π / 2 + 2t ・ ・ ・ (2)
As a result, even when the shock absorbing portion 7 is deformed toward the bumper beam M so that the recess 9 is largely crushed, as shown in FIG. 3B, the deformation regulating portion 8 is deformed before the sensor tube 5 is completely crushed. It is possible to regulate the deformation of the sensor tube 5 by abutting on M.

Next, the operation of the first embodiment will be described.
First, as shown in FIG. 1, the vehicle is driven and the colliding body collides with the bumper face F of the vehicle. As shown in FIG. 2, a shock absorbing unit 7 is arranged between the bumper face F arranged at the front of the vehicle and the bumper beam M, and the shock absorbing unit 7 responds to the impact from the collision body by the bumper beam M. It transforms so that it is crushed toward. As a result, the impact absorbing unit 7 can absorb the impact from the colliding body.

Here, a recess 9 that opens on the bumper beam M side is formed on the rear surface of the shock absorbing portion 7, and the sensor tube 5 is arranged in this recess 9. Therefore, due to the deformation of the shock absorbing portion 7, the sensor tube 5 is pressed between the shock absorbing portion 7 and the bumper beam M in response to the impact from the colliding body.
At this time, as shown in FIG. 4A, when the sensor tube 5 is pressed so as not to be completely crushed, that is, when one side side and the other side side of the sensor tube 5 communicate with each other. Propagates the pressure wave generated in the propagation path 5a in the sensor tube 5 so as to reciprocate between one end and the other end of the sensor tube 5. Therefore, as shown in FIG. 4B, the intensity of the pressure wave detected by the pressure sensors 6a and 6b has little waveform turbulence, and the sum of their integrals is a substantially constant value. In this way, the strength of the pressure wave having a correlation with the impact energy of the colliding body can be detected by the pressure sensors 6a and 6b.

On the other hand, as shown in FIG. 5A, when the sensor tube 5 is pressed so as to be completely crushed, the pressure wave generated in the propagation path 5a is between one end of the sensor tube 5 and the pressing position. Propagates in a reciprocating manner and propagates in a reciprocating manner between the other end of the sensor tube 5 and the pressing position. Therefore, for example, when a position close to one end of the sensor tube 5 is pressed, a pressure wave detected by the pressure sensor 6a arranged at one end of the sensor tube 5 as shown in FIG. 5 (b). The intensity of the pressure wave becomes very large as compared with the intensity of the pressure wave detected by the pressure sensor 6b arranged at the other end of the sensor tube 5, and it becomes difficult to obtain a stable sum of integration.

Therefore, in the present invention, as shown in FIG. 2, the deformation regulating portion 8 that regulates the deformation of the sensor tube 5 in the middle is arranged in the recess 9 of the shock absorbing portion 7, and the sensor is placed in the accommodating groove 10 of the deformation regulating portion 8. Accommodates tube 5.
Here, when the shock absorbing portion 7 is pressed toward the bumper beam M in response to the impact of the colliding body, the accommodation groove 10 of the deformation regulating portion 8 is formed to be shallower than the diameter L of the sensor tube 5, so that the sensor tube is formed. 5 abuts on the bumper beam M before the deformation regulating portion 8. As a result, the sensor tube 5 is pressed by the bumper beam M, and the pressure wave propagates in the propagation path 5a.

Subsequently, the sensor tube 5 is further pressed by the bumper beam M. At this time, as shown in FIG. 3A, the depth A of the accommodating groove 10 is formed so as to satisfy the above equation (1). Therefore, as shown in FIG. 3B, the deformation regulating portion 8 comes into contact with the bumper beam M before the sensor tube 5 is completely crushed. Since the deformation regulating portion 8 is composed of, for example, metal and synthetic resin and has higher rigidity than the shock absorbing portion 7, it supports the shock absorbing portion 7 so as to maintain the size of the recess 9, thereby the sensor tube 5. Deformation is regulated. In this way, the deformation regulating unit 8 regulates the deformation of the sensor tube 5, so that even if the impact energy of the colliding body is large, the pressure wave reciprocates between one end and the other end of the sensor tube 5. Can be propagated, and a pressure wave having a stable waveform can be detected by the pressure sensors 6a and 6b.
Further, the width B of the accommodating groove 10 is formed so as to satisfy the above equation (2). Therefore, the sensor tube 5 can be smoothly deformed without coming into contact with the side plate portion 8b of the deformation regulating portion 8, and the pressure wave can be stably detected.

In this way, when the pressure wave propagating in the propagation path 5a of the sensor tube 5 is detected by the pressure sensors 6a and 6b, the calculation unit 2 outputs the detection from the pressure sensors 6a and 6b as shown in FIG. Calculate the strength of the pressure wave based on the signal. Then, the deployment control unit 3 determines whether or not the vehicle has collided with the colliding body based on the intensity of the pressure wave calculated by the calculation unit 2, and if it is determined that the vehicle has collided, the airbag 4 is deployed. ..

According to the present embodiment, the deformation regulating portion 8 has a higher rigidity than the shock absorbing portion 7 so that the accommodating groove 10 is formed shallower than the diameter L of the sensor tube 5 and the deformation of the sensor tube 5 is regulated. Even when the impact energy of the colliding body is large, a stable pressure wave having a correlation with the impact energy can be detected by the pressure sensors 6a and 6b, and the impact of the vehicle collision can be accurately detected.

Embodiment 2
In the above-described first embodiment, the deformation restricting unit 8 is formed so that the depth A of the accommodating groove 10 satisfies the above-mentioned equation (1), but is formed so as to restrict the deformation of the sensor tube 5. However, it is not limited to this.
For example, as shown in FIG. 6, the deformation regulating unit 21 can be arranged in place of the deformation regulating unit 8 of the first embodiment.

The deformation regulating portion 21 is formed with a housing groove 22 that opens on the bumper beam M side. That is, the deformation restricting portion 21 is configured by connecting a bottom plate portion 21a arranged along the bottom surface of the recess 9 and a pair of side plate portions 21b arranged so as to face each other along the side surface of the recess 9. Has been done. The width B of the accommodating groove 22 is formed so as to satisfy the following equation (3).
B <d ・ π / 2 + 2t ・ ・ ・ (3)
As a result, the deformation regulating portion 21 can regulate the deformation of the sensor tube 5 by supporting the sensor tube 5 from the outside with the pair of side plate portions 21b before the sensor tube 5 is completely crushed.

According to the present embodiment, since the width B of the accommodating groove 22 of the deformation regulating portion 21 is formed so as to satisfy the above equation (3), the sensor tube 5 is deformed before the sensor tube 5 is completely crushed. Can be regulated to accurately detect the impact of a vehicle collision.

In the above-described first and second embodiments, the deformation restricting portion is arranged so as to extend in the vehicle width direction, but it may be arranged in the recess 9 of the shock absorbing portion 7, and is limited to this. It's not a thing. For example, a plurality of deformation restricting portions may be arranged so as to be arranged at intervals in the recesses 9 of the shock absorbing portion 7.

Further, in the above-described first and second embodiments, the shock absorbing portion 7 is arranged so as to abut on the bumper beam M, but it is sufficient if the sensor tube 5 can be pressed by the deformation of the shock absorbing portion 7. Not limited. For example, the impact absorbing unit 7 can be arranged at intervals on the front side of the bumper beam M so as to abut on the bumper beam M in response to a vehicle collision.
Further, in the above-described first and second embodiments, the shock absorbing portion 7 is arranged so as to abut on the bumper beam M, but the sensor tube 5 may be arranged so as to abut on the bumper beam M. For example, the recess 9 is formed shallower than the diameter L of the sensor tube 5 so that the rear portion of the sensor tube 5 protrudes outside the recess 9 of the shock absorbing portion 7, and the rear portion of the sensor tube 5 protruding outside the recess 9 is the bumper beam M. The shock absorbing portion 7 can be arranged so as to come into contact with the shock absorbing portion 7.

1 Collision detection device, 2 Calculation unit, 3 Deployment control unit, 4 Airbag, 5 Sensor tube, 5a Propagation path, 6a, 6b pressure sensor, 7 Impact absorption unit, 8,21 Deformation control unit, 8a, 21a Bottom plate unit, 8b, 21b side plate, 9 recesses, 10,22 accommodating grooves, F bumper face, M bumper beam, L sensor tube diameter, N crushed sensor tube, t wall thickness, d inner diameter, S thickness, W width, A depth , B width.

Claims (5)

A shock absorbing portion that is arranged so as to extend in the vehicle width direction on the front side of the bumper beam of the vehicle and has a recess that opens on the bumper beam side and is deformed by the collision of the vehicle to absorb the impact.
A deformation restricting portion that is arranged in the recess and has an accommodating groove that opens on the bumper beam side.
A sensor tube that has a tube shape and is formed so as to extend in the vehicle width direction and is accommodated in the accommodating groove, and is pressed by the deformation of the impact absorbing portion to generate a pressure wave inside.
A pressure sensor connected to the sensor tube to detect the pressure wave is provided.
In the deformation restricting portion, the accommodating groove is formed shallower than the diameter of the sensor tube, has higher rigidity than the shock absorbing portion , and the shock absorbing portion is deformed toward the bumper beam so that the recess is largely crushed. Even in such a case, the collision detecting device is characterized in that the deformation regulating portion abuts on the bumper beam to regulate the deformation of the sensor tube before the sensor tube is completely crushed . Assuming that the wall thickness of the sensor tube is t, the depth A of the accommodating groove is
A> 2t
The collision detection device according to claim 1, which is formed so as to satisfy the above conditions. Assuming that the wall thickness of the sensor tube is t and the inner diameter of the sensor tube is d, the width B of the accommodating groove is
B ≧ d ・ π / 2 + 2t
The collision detection device according to claim 2, which is formed so as to satisfy the above conditions. Assuming that the wall thickness of the sensor tube is t and the inner diameter of the sensor tube is d, the width B of the accommodating groove is
B <d ・ π / 2 + 2t
The collision detection device according to claim 1 or 2, which is formed so as to satisfy the above conditions. The collision detection device according to any one of claims 1 to 4, wherein at least one of the shock absorbing portion and the sensor tube is arranged so as to abut on the bumper beam.

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