JP2019172152A - Collision detection device - Google Patents

Abstract

To provide a collision detection device which accurately detects an impact caused by a collision of a vehicle.SOLUTION: A collision detection device includes: an impact absorption part 7 which is disposed at the front side of a bumper beam M of a vehicle so as to extend in a vehicle width direction, formed with a recessed part 9 opening to the bumper beam M side, and deformed by a collision of the vehicle to absorb an impact; a deformation restriction part 8 which is disposed at the recessed part 9 and formed with a storage groove 10 opening to the bumper beam M side; a sensor tube 5 which has a tubular shape, is formed so as to extend in the vehicle width direction, is stored in the storage groove 10, and is pressed by deformation of the impact absorption part 7 to generate pressure waves therein; and pressure sensors 6a and 6b which are connected to the sensor tube 5 and detect the pressure waves. In the deformation restriction part 8, the storage groove 10 is formed shallower than a diameter L of the sensor tube 5, and the deformation restriction part 8 has rigidity higher than that of the impact absorption part 7 so as to restrict deformation of the sensor tube 5.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, when a colliding 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 accommodated in a recess of an impact absorbing portion disposed on the front side of a bumper beam of a vehicle, and pressure waves are generated in the sensor tube by pressing the sensor tube in response to the impact of the collision. Occurs. A vehicle collision can be detected by detecting a pressure wave generated in the sensor tube. Here, the collision detection device is required to stably detect a vehicle collision.

  Therefore, as a technique for stably detecting a vehicle collision, for example, Patent Document 1 discloses a vehicle bumper including a pedestrian collision detection sensor that detects a collision without depending on a change in the hardness of an impact absorbing portion due to temperature. A structure has been proposed. In this vehicle bumper structure, a convex holding portion that holds 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 smaller than the diameter of the sensor tube, the sensor tube comes into contact with the bumper beam before the holding portion. For this reason, the sensor tube is pressed without depending on the change in hardness due to the temperature of the shock absorbing portion, and the collision of the vehicle can be detected stably.

JP 2017-7368 A

  However, since the deformation of the sensor tube due to the press is not regulated in the middle of the vehicle bumper structure of Patent Document 1, 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 an impact of a vehicle collision.

  The collision detection device according to the present invention is disposed so as to extend in the vehicle width direction on the front side of the bumper beam of the vehicle and is formed with a recess opening on the bumper beam side, and is deformed by the collision of the vehicle to absorb the shock. An impact absorbing portion that is disposed in the concave portion, and a deformation restricting portion that is formed with an accommodation groove that opens to the bumper beam side, has a tubular shape and is formed to extend in the vehicle width direction, and is accommodated in the accommodation groove, A sensor tube that is pressed by deformation of the shock absorbing portion to generate a pressure wave therein; and a pressure sensor that is connected to the sensor tube and detects the pressure wave. It is formed to be shallower than the diameter of the sensor tube and has higher rigidity than the shock absorbing part so as to restrict deformation of the sensor tube.

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

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

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

  Further, it is preferable that at least one of the impact absorbing portion and the sensor tube is disposed so as to contact the bumper beam.

  According to this invention, the deformation restricting portion is formed so that the housing groove is shallower than the diameter of the sensor tube, and has a higher rigidity than the shock absorbing portion so as to restrict the deformation of the sensor tube. It is 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 a collision detection apparatus. It is sectional drawing which shows a mode that a deformation | transformation control part controls a deformation | transformation of a sensor tube. It is a figure which shows a mode that a pressure wave propagates through a sensor tube. It is a figure which shows a mode that a pressure wave propagates through the crushed sensor tube. 6 is a cross-sectional view showing a configuration of a deformation restricting portion in Embodiment 2. FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows a configuration of an airbag apparatus provided with a collision detection apparatus according to Embodiment 1 of the present invention. The airbag device includes 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 includes a sensor tube 5 and a pair of pressure sensors 6a and 6b, and is disposed inside a bumper face F provided at the front portion of the vehicle.
The sensor tube 5 is disposed so as to extend in the vehicle width direction, has a circular tube shape, and has a propagation path communicating from one end to the other end. The sensor tube 5 is deformed according to the impact of the collision body colliding with the vehicle, and the pressure wave generated by the deformation is propagated to the one end side and the other end side through the propagation path.

  The pressure sensors 6a and 6b are connected to both ends of the sensor tube 5 and detect pressure waves that have propagated through the propagation path of the sensor tube 5. For example, a sensor using a diaphragm can be used.

The computing 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 collision 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 it is determined that the vehicle has collided with the collision body, the deployment controller 3 injects a deployment gas from an inflator (not shown) to deploy the airbag 4. On the other hand, when the deployment control unit 3 determines that the vehicle has not collided with the colliding body, the inflator is not driven 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 rear edge of the front hood by injecting development gas from an inflator (not shown).

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

  The deformation restricting portion 8 is disposed so as to extend in the vehicle width direction along the concave portion 9 of the shock absorbing portion 7, and an accommodation groove 10 that opens to the bumper beam M side is formed. That is, the deformation restricting portion 8 is configured by connecting a bottom plate portion 8 a disposed along the bottom surface of the recess 9 and a pair of side plate portions 8 b disposed so as to face each other along the side surface of the recess 9. Has been. The deformation restricting 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 outside the housing groove 10. The deformation restricting portion 8 has higher rigidity than the shock absorbing portion 7 so as to restrict the deformation of the sensor tube 5 and can be made of, for example, metal and synthetic resin.

As shown in FIG. 3A, the housing groove 10 is formed larger than the sensor tube N in a completely crushed state. Here, when the thickness of the sensor tube 5 is t and the inner diameter of the sensor tube 5 is d, the completely collapsed sensor tube N can be expressed as 2t in thickness S and d · π / 2 + 2t in width W. it can. For this reason, the depth A of the accommodation groove 10 is formed so as to satisfy the following expression (1), and the width B of the accommodation groove 10 is formed so as to satisfy the following expression (2).
A> 2t (1)
B ≧ d · π / 2 + 2t (2)
Thereby, even when the shock absorbing portion 7 is deformed toward the bumper beam M so that the concave portion 9 is largely crushed, as shown in FIG. 3B, the deformation restricting portion 8 is moved to the bumper beam before the sensor tube 5 is completely crushed. The deformation of the sensor tube 5 can be regulated by abutting M.

Next, the operation of the first embodiment will be described.
First, as shown in FIG. 1, the vehicle travels and a colliding body collides with the bumper face F of the vehicle. As shown in FIG. 2, an impact absorbing portion 7 is disposed between a bumper face F and a bumper beam M disposed at the front portion of the vehicle, and the impact absorbing portion 7 responds to an impact from a collision object. Deforms to be crushed toward Thereby, the impact absorption part 7 can absorb the impact from a collision body.

Here, a recess 9 that opens to the bumper beam M side is formed on the rear surface of the shock absorber 7, and the sensor tube 5 is disposed in the recess 9. For this reason, the deformation of the impact absorbing portion 7 causes the sensor tube 5 to be pressed between the impact absorbing portion 7 and the bumper beam M in accordance with the impact from the collision 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 of the sensor tube 5 is in communication with the other side. Propagates so that a pressure wave generated in the propagation path 5 a in the sensor tube 5 reciprocates between one end and the other end of the sensor tube 5. For this reason, the intensity of the pressure wave detected by the pressure sensors 6a and 6b is less disturbed in the waveform as shown in FIG. 4B, and the integrated sum of these is a substantially constant value. In this way, the intensity of the pressure wave having a correlation with the impact energy of the collision object 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, a pressure wave generated in the propagation path 5a is generated between one end of the sensor tube 5 and the pressed position. And so as to reciprocate between the other end of the sensor tube 5 and the pressed position. For this reason, for example, when a position close to one end of the sensor tube 5 is pressed, the pressure wave detected by the pressure sensor 6a disposed at one end of the sensor tube 5 as shown in FIG. Is much larger than the intensity of the pressure wave detected by the pressure sensor 6b disposed at the other end of the sensor tube 5, making it difficult to obtain a stable integral sum.

Therefore, in the present invention, as shown in FIG. 2, the deformation restricting portion 8 for restricting the deformation of the sensor tube 5 is disposed in the recess 9 of the shock absorbing portion 7, and the sensor is placed in the accommodation groove 10 of the deformation restricting portion 8. The tube 5 is accommodated.
Here, when the impact absorbing portion 7 is pressed toward the bumper beam M in response to the impact of the collision body, the housing groove 10 of the deformation restricting portion 8 is formed shallower than the diameter L of the sensor tube 5, so that the sensor tube 5 abuts against the bumper beam M before the deformation restricting portion 8. Thereby, the sensor tube 5 is pressed by the bumper beam M, and a pressure wave propagates through 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 housing groove 10 is formed so as to satisfy the above expression (1). For this reason, as shown in FIG. 3B, the deformation restricting portion 8 contacts the bumper beam M before the sensor tube 5 is completely crushed. Since the deformation restricting portion 8 is made of, for example, metal and synthetic resin and has higher rigidity than the shock absorbing portion 7, the deformation restricting portion 8 supports the shock absorbing portion 7 so as to maintain the size of the concave portion 9, thereby the sensor tube 5. The deformation of is regulated. As described above, the deformation restricting portion 8 restricts the deformation of the sensor tube 5 so that the pressure wave reciprocates between one end and the other end of the sensor tube 5 even when the impact energy of the collision body is large. Can be propagated, and a pressure wave with a stable waveform can be detected by the pressure sensors 6a and 6b.
Further, the width B of the receiving groove 10 is formed so as to satisfy the above expression (2). For this reason, the sensor tube 5 can be smoothly deformed without contacting the side plate portion 8b of the deformation restricting portion 8, and the pressure wave can be detected stably.

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

  According to the present embodiment, the deformation restricting portion 8 is formed so that the receiving groove 10 is shallower than the diameter L of the sensor tube 5 and has higher rigidity than the shock absorbing portion 7 so as to restrict the deformation of the sensor tube 5. Even when the impact energy of the collision 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 with which the vehicle collides can be accurately detected.

Embodiment 2
In the first embodiment, the deformation restricting portion 8 is formed so that the depth A of the housing groove 10 satisfies the above expression (1), but is formed so as to restrict the deformation of the sensor tube 5. What is necessary is not limited to this.
For example, as shown in FIG. 6, a deformation restricting portion 21 can be arranged instead of the deformation restricting portion 8 of the first embodiment.

The deformation restricting portion 21 is formed with an accommodation groove 22 that opens to the bumper beam M side. That is, the deformation restricting portion 21 is configured by connecting a bottom plate portion 21 a disposed along the bottom surface of the recess 9 and a pair of side plate portions 21 b disposed so as to face each other along the side surface of the recess 9. Has been. And the width B of the accommodation groove | channel 22 is formed so that the following (3) Formula may be satisfy | filled.
B <d · π / 2 + 2t (3)
Thereby, before the sensor tube 5 is completely crushed, the deformation | transformation control part 21 can support the sensor tube 5 from the outer side with a pair of side plate part 21b, and can control a deformation | transformation of the sensor tube 5. FIG.

  According to the present embodiment, since the width B of the accommodation groove 22 of the deformation restricting portion 21 is formed so as to satisfy the above expression (3), the deformation of the sensor tube 5 before the sensor tube 5 is completely crushed. It is possible to accurately detect the impact of the collision of the vehicle.

  In the first and second embodiments, the deformation restricting portion is disposed so as to extend in the vehicle width direction. However, the deformation restricting portion only needs to be disposed in the concave portion 9 of the shock absorbing portion 7, and is not limited thereto. It is not a thing. For example, a plurality of deformation restricting portions can be arranged in the recess 9 of the shock absorbing portion 7 so as to be arranged at intervals.

In the first and second embodiments, the shock absorber 7 is disposed so as to contact the bumper beam M. However, it is sufficient that the sensor tube 5 can be pressed by the deformation of the shock absorber 7. It is not limited. For example, the impact absorbing portion 7 can be arranged at a distance from the front side of the bumper beam M so as to come into contact with the bumper beam M in response to a vehicle collision.
In the first and second embodiments, the shock absorber 7 is disposed so as to contact the bumper beam M. However, the sensor tube 5 may be disposed so as to contact the bumper beam M. For example, the concave portion 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 concave portion 9 of the shock absorbing portion 7, and the rear portion of the sensor tube 5 that protrudes outside the concave portion 9 is provided as the bumper beam M. The shock absorbing portion 7 can be disposed so as to abut against the.

  DESCRIPTION OF SYMBOLS 1 Collision detection apparatus, 2 calculating part, 3 Deployment control part, 4 Air bag, 5 Sensor tube, 5a Propagation path, 6a, 6b Pressure sensor, 7 Shock absorption part, 8, 21 Deformation restriction part, 8a, 21a Bottom plate part, 8b, 21b Side plate, 9 recess, 10, 22 receiving groove, F bumper face, M bumper beam, L sensor tube diameter, N collapsed sensor tube, t wall thickness, d inner diameter, S thickness, W width, A depth , B width.

Claims (5)

An impact absorbing portion that is disposed on the front side of the bumper beam of the vehicle so as to extend in the vehicle width direction and that has a recess that opens on the bumper beam side, and that is deformed by the collision of the vehicle and absorbs an impact;
A deformation restricting portion that is disposed in the recess and has an accommodation groove that opens to the bumper beam side;
A sensor tube that has a tubular shape and is formed so as to extend in the vehicle width direction, is accommodated in the accommodation groove, and is pressed by deformation of the shock absorbing portion to generate a pressure wave inside;
A pressure sensor connected to the sensor tube for detecting the pressure wave;
The collision detection device according to claim 1, wherein the deformation restricting portion has the housing groove formed shallower than the diameter of the sensor tube, and has higher rigidity than the shock absorbing portion so as to restrict the deformation of the sensor tube. When the thickness of the sensor tube is t, the depth A of the receiving groove is
A> 2t
The collision detection device according to claim 1, wherein the collision detection device is formed so as to satisfy the above. When the inner diameter of the sensor tube is d, the width B of the receiving groove is
B ≧ d · π / 2 + 2t
The collision detection device according to claim 2, wherein the collision detection device is formed so as to satisfy the above. When the thickness of the sensor tube is t and the inner diameter of the sensor tube is d, the width B of the receiving groove is
B <d · π / 2 + 2t
The collision detection device according to claim 1, wherein the collision detection device is formed so as to satisfy the above. The collision detection device according to any one of claims 1 to 4, wherein at least one of the impact absorbing portion and the sensor tube is disposed so as to contact the bumper beam.