JPH06115406A - Side collision detection device for vehicle - Google Patents

Abstract

PURPOSE:To provide such a side collision detection device that can be constituted at a low price and can detect collision speedily regardless of its collision part. CONSTITUTION:A side collision detection device is provided, inside of its side door main body, with a side door beam 13 for reinforcement, which is extended in the longitudinal direction of a vehicle, and is formed with a recessed part in the longitudinal direction, a piezoelectric element 20 which is extended along the longitudinal direction of the side door beam 13 inside of a recessed part and outputs signals according to deformation of the side door beam 13, and a detection circuit 30 which detects collision with the side face of the vehicle according to the output signals from the piezoelectric element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side collision detection device for detecting the collision of an external object on the side surface of a vehicle.

[0002]

2. Description of the Related Art As a conventional side collision detection device of this type, for example, one disclosed in Japanese Utility Model Laid-Open No. 3-112455 is known. This will be described with reference to FIG. In FIG. 12, a pair of strain gauges 202 for detecting deformation of the side door beam 201 are attached to an outer surface and an inner surface of a reinforcing side door beam 201 extending in a vehicle front-rear direction inside a vehicle door body 200. A Wheatstone bridge circuit is formed by the pair of strain gauges 202. Now, for example, when another vehicle collides with the side surface of the vehicle and the side door beam 201 is largely deformed and the strain gauge 202 is distorted, the output of the Wheatstone bridge circuit becomes a predetermined value or more. Automatically expands and expands.

[0003]

However, when the strain gauge 202 is used as the deformation detecting element of the side door beam 201 as described above, there are the following problems (1) to (5). (1) Since the range that can be detected by one strain gauge 202 is only a very narrow portion of the side door beam 201, it is necessary to mount a plurality of strain gauges in order to quickly detect a collision regardless of the collision location. . (2) The size of one strain gauge 202 is usually 1 cm ²
As described below, in order to bond such a small element to the side door beam 201 while maintaining the bonding strength, it is necessary to strictly control the bonding conditions. (3) Since the strain gauge 202 generally has low durability, if the strain gauge 202 is exposed, it is necessary to pay close attention to the storage of the side door beam 201 to which the strain gauge 202 is attached and the attachment to the vehicle. Sex decreases. In order to prevent such a decrease in workability, it is necessary to protect the strain gauge 202 with a robust protective case before use. (4) It is necessary to magnetically shield in order to prevent malfunction due to the influence of electromagnetic noise. (5) Due to the reasons (1) to (4) above, cost increase is inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a side collision detection device which has an inexpensive structure and can detect a collision quickly regardless of the collision location.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, a side collision detection device for a vehicle according to the present invention extends in the vehicle front-rear direction inside a side door body, and A reinforcing side door beam 13 having a recess formed in the longitudinal direction, and a piezoelectric element 20 extending in the recess along the longitudinal direction of the side door beam 13 and outputting a signal according to the amount of deformation of the side door beam 13. And a detection circuit 30 for detecting a collision on the side surface of the vehicle based on the output signal of the piezoelectric element, thereby solving the above-mentioned problems. Particularly, the second aspect is that the detection circuit is fixed in the recess of the side door beam. According to a third aspect of the invention, the piezoelectric element is provided with flexibility. Further, in the present invention, the concave portion is formed by forming the side door beam in a hollow shape. Furthermore, claim 5
Is a piezoelectric element installed on the inner surface of a vehicle interior inside a hollow side door beam. According to a sixth aspect of the invention, a filling material is provided which is filled in the hollow interior of the side door beam and fixes the piezoelectric element. Further, a seventh aspect of the present invention is that the side door beam is made of a material having a magnetic shield function.

[0006]

Since the piezoelectric element 20 is extended in the longitudinal direction of the side door beam 13, the detection range of the collision point by the piezoelectric element 20 is widened, and the collision can be detected reliably and promptly. Further, since the piezoelectric element 20 is attached to the concave portion of the side door beam, it is possible to prevent another object from colliding with the piezoelectric element 20. In particular, in the invention of claim 2, since the detection circuit 30 is provided in the recess of the side door beam 13, the connection wiring between the piezoelectric element 20 and the detection circuit 30 can be shortened. Therefore, the influence of electromagnetic wave noise from the outside can be suppressed to a minimum, and the strange capacitance generated between the wirings is reduced. According to the third aspect of the invention, since the piezoelectric element having flexibility is used, damage is unlikely to occur even if the piezoelectric element is hit by another object. Claim 4
In the invention, the side door beam is hollow and the piezoelectric element is installed inside the hollow. Therefore, the piezoelectric element is more surely protected by the side door beam. Here, when the side door beam 13 is deformed due to a side collision, the amount of extension in the longitudinal direction of the side door beam 13 is larger on the inner side (cabin side) than on the outer side. In the invention according to claim 5, the side door beam 13 in which the piezoelectric element 20 has a large expansion amount at the time of collision
It is arranged on the inner surface of the vehicle interior side. Therefore, the amount of deformation of the piezoelectric element 20 at the time of a collision becomes larger than that in the case where the piezoelectric element 20 is arranged along the outer inner surface, and the collision can be detected more reliably. Further, in the invention of claim 6, the piezoelectric element is fixed by the filler. Further, in the invention of claim 7, since the detection circuit 30 is provided in the side door beam 13 having a magnetic shield function, the influence of noise can be avoided without separately providing a shield member.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a plan sectional view showing the side door 10 provided on the right side surface of the vehicle. A side door beam 13 for reinforcement is extended between the outer panel 11 and the inner panel 12 forming the door body in the vehicle front-rear direction, and both ends thereof are fixed to the front and rear ends of the door. As shown in FIG. 1, the side door beam 13 is formed of a cylindrical body made of a metal material, and the inner surface of the cylindrical body forms a longitudinal recess. The piezoelectric film 20 is provided inside the side door beam 13 over substantially the entire length in the longitudinal direction. As shown in FIG. 3, the piezoelectric film 20 is formed by bonding a piezoelectric element 23 such as PVDF (polyvinylidene fluoride) between a pair of insulating films 21 and 22 made of, for example, a polyimide-based material over substantially the entire length. , Has flexibility. The piezoelectric film 20 is arranged along the inner surface (vehicle compartment side) of the side door beam 13 as shown in FIG. The side door beam 13 is body-grounded via the door body.

Reference numeral 30 in FIG. 1 is a detection circuit for detecting the presence or absence of a collision on the side surface of the vehicle based on a detection signal output from the piezoelectric film 20, and this detection circuit 30 together with the piezoelectric film 20 has a foamed filler 41. It is embedded in the side door beam 13 via. FIG. 4 shows this detection circuit 3
A block diagram of 0 is shown, and 31 is a buffer amplifier for amplifying the detection signal of the piezoelectric element 23. Buffer amplifier 3
The signal amplified by 1 passes through a high-pass filter 32 for reducing low-frequency noise due to the pyroelectric effect and a low-pass filter 33 for removing high-frequency noise due to vibrations of the vehicle body and the engine, and then a differentiating circuit 34. Are differentiated by and input to the comparator 35. The comparator 35 compares the input signal with the reference signal and inputs a high level signal to the squib driver 36 when the input signal is higher than the reference signal. The squib driver 36 outputs a squib drive signal in response to the high level signal input from the comparator 35, and the squib (inflator ignition device) 42 that constitutes an airbag device (not shown) in accordance with the drive signal. Ignites the inflator and inflates and deploys the airbag.

Here, FIG. 5 shows a signal waveform diagram in each part of the detection circuit 30, (a) shows an input signal from the piezoelectric film 20, and (b) shows a signal after passing through the filters 32 and 33. , (C) is the output signal of the differentiating circuit 34,
(D) shows the output signals of the comparator 35, respectively.

Next, the operation of the embodiment will be described. As shown in FIG. 6, when another vehicle collides with the door 10, for example, the outer panel 11 is first deformed, and then the side door beam 13 is deformed as shown in FIG. 7. Thereby, the piezoelectric element 23 forming the piezoelectric film 20 in the side door beam 13 is formed.
Is deformed, and the detection signal increases as indicated by A in FIG. Along with this, the output signals of the filter 33 and the differentiating circuit 34 also increase as shown in FIGS. 5B and 5C, and when the output signal of the differentiating circuit 34 exceeds the reference value, the comparator 35 causes the comparator 35 of FIG. A high level signal is output as shown in (d). In response to this high level signal, the squib driver 36 operates the squib 42 to activate the inflator and inflate and deploy the airbag.

According to this embodiment, since the piezoelectric film 20 is extended over substantially the entire length in the longitudinal direction of the side door beam 13, the collision of the door 10 at any position in the vehicle front-rear direction can be reliably and quickly performed. Can be detected. Where the door 1
When the side door beam 13 is deformed as shown in FIG. 7 due to the collision with 0, the amount of extension of the side door beam 13 in the direction of the arrow is greater on the inner side (cabin side) than on the outer side. In the present embodiment, as shown in FIG. 1, the piezoelectric film 20 is arranged along the inner inner surface of the side door beam 13 which has a large amount of expansion at the time of collision. In this case, the deformation amount of the piezoelectric element 23 becomes large and the collision can be detected more reliably. Moreover, since the foaming agent 41 is filled in the side door beam 13, the fixing strength of the piezoelectric film 23 and the detection circuit 30 is increased.

Further, the piezoelectric element 23 is used as the side door beam 1
Since it is housed inside 3, the strict attachment management of the piezoelectric element 23 is unnecessary, and the side door beam 31
It is not necessary to pay close attention when storing and mounting on the vehicle, and workability can be improved. Further, it is not necessary to cover the piezoelectric element 23 with a protective case or the like. Further, since the side door beam 13 for accommodating the piezoelectric film 20 and the detection circuit 30 is made of a metal material and is body-grounded via the door body, the side door beam 13 serves as a magnetic shield and a special shield member. Even if not provided, an adverse effect due to electromagnetic wave noise from the outside can be avoided and erroneous detection can be prevented. Further, by providing the detection circuit 30 in the side door beam 13, the detection circuit 3
The connection wiring between 0 and the piezoelectric film 20 can be shortened, and the influence of noise can be minimized. In addition, since the detection circuit 30 is molded and fixed with the filler 40, failure of the detection circuit 30 due to vibration of the vehicle can be prevented, and since a foaming agent is used as the filler 40, the weight can be reduced. Although the piezoelectric element 23 outputs a signal corresponding to the temperature change due to the pyroelectric effect, since the high-pass filter 32 is provided in the detection circuit 30, low frequency noise (DC voltage) due to the pyroelectric effect is removed. There is no risk of false detection.

8 to 11 show various other embodiments. In the above-described embodiment, the entire interior of the side door beam 13 is filled with the filler 41. However, if the piezoelectric film 20 and the detection circuit 30 can be fixed within the side door beam 13, for example, the filler 41 can be removed as shown in FIG. Only the inner half is required, which allows cost reduction. Further, FIG. 9 shows an example in which the piezoelectric film 20 is directly adhered to the inner wall of the side door beam 13 on the inside of the vehicle. In this case, only the detection circuit 30 may be covered and fixed with the filler 41. In this case, even if a part of the piezoelectric film 20 is peeled off, the waveform peak at the time of collision is slightly lowered and the detection timing is not delayed. Furthermore, FIG.
Reference numeral 0 denotes a pair of support rods 51 and 52 projectingly provided in the side door beam 13, and both ends of the piezoelectric film 20 are supported and fixed. Also in this case, only the detection circuit 30 needs to be covered with the filler 41. . However, with this fixing method, the piezoelectric film 20 may vibrate due to the vibration of the vehicle, and therefore it is necessary to provide a filter in the detection circuit 30 for removing the influence of the vibration.

In the above, the cylindrical side door beam 13 is formed.
11 shows an example in which the U-shaped side door beam 130 is used. In FIG.
The piezoelectric film 20 is bonded to the inner surface of the U-shaped side door beam 130 made of a metal material, and the detection circuit 30 is arranged in the vicinity thereof. The piezoelectric film 20 and the detection circuit 30 are covered with a foam filler 40, and a conductive plate member 61 is arranged on the outer side thereof. This also provides the same effect as the above. In particular, the piezoelectric film 20 and the detection circuit 30 are fixed to the space formed by the side door beam 130 and the conductive plate member 61 via the filler 41, so that an electrostatic shield effect can be obtained. .

Although the example in which the piezoelectric film 20 is used as the detection element has been described above, piezoelectric rubber or the like may be used instead of this. By using these materials, even when the piezoelectric element is exposed, damage due to collision or the like is unlikely to occur, and workability can be improved. Although the side door beam made of a metal material is used, it may be made of resin or the like as long as the required strength can be obtained. In this case, it is necessary to cover the inner peripheral surface of the side door beam with a metal foil or the like for electrostatic shielding, but the cost can be reduced compared to the case where a new shield member is provided. Further, the detection circuit 30 may be installed outside the side door beam. Although the squib driver 35 is provided in the detection circuit 30, it may be provided separately from the detection circuit 30. Furthermore, the filler is not limited to foaming agents.

[0017]

As described above, according to the present invention, a side surface collision of a vehicle is detected by a piezoelectric element extending in the longitudinal direction in the recess or hollow inside of the side door beam. A collision can be detected reliably and quickly at a location, strict piezoelectric element mounting management is not required, and side door beams can be easily mounted and stored. Furthermore, a flexible piezoelectric element has high durability,
The effect is obtained that it is not necessary to cover with a protective case or the like. Therefore, according to the present invention, the cost can be remarkably reduced as compared with the conventional case where the strain gauge is used.
Particularly, according to the invention of claim 2, since the detection circuit is embedded in the side door beam, the influence of noise can be minimized. Further, according to the invention of claim 5, since the piezoelectric element is arranged on the inside of the hollow side door beam (the deformation amount is larger than that on the outside), the collision can be detected more reliably than when the piezoelectric element is arranged on the outside. Further, according to the invention of claim 6, the mounting strength of the piezoelectric element is improved by the filler. Further, according to the invention of claim 7, since the piezoelectric element or the detection circuit is provided in the hollow side door beam formed so as to have a magnetic shield function, the influence of noise is not provided separately. Can be avoided.

[Brief description of drawings]

FIG. 1 is a sectional view of a side door beam showing a configuration of a side collision detection device for a vehicle according to the present invention.

FIG. 2 is a plan view of a vehicle door.

FIG. 3 is a perspective view showing a configuration of a piezoelectric film.

FIG. 4 is a block diagram showing a configuration of a detection circuit.

FIG. 5 is a waveform diagram showing an output waveform of each part of the detection circuit.

FIG. 6 is a plan view showing a state where an external object collides with the door.

FIG. 7 is a plan view showing deformation of the side door beam at the time of collision.

FIG. 8 is a vertical sectional view of a side door beam showing another embodiment of the side collision detection device.

9A and 9B show another embodiment of the side collision detection device, FIG. 9A is a vertical sectional view of a side door beam, and FIG. 9B is a sectional view taken along line AA of FIG. 9A.

FIG. 10 shows another embodiment of the side collision detection device, (a)
Is a vertical sectional view of the side door beam, (b) is (a)
FIG. 6 is a sectional view taken along line BB of FIG.

11A and 11B show another embodiment using a U-shaped side door beam, in which FIG. 11A is a perspective view and FIG. 11B is a sectional view taken along line CC of FIG.

FIG. 12 is a perspective view showing a conventional side collision detection device.

[Explanation of symbols]

 10 Door 13 Side Door Beam 20 Piezoelectric Film 21,22 Insulating Film 23 Piezoelectric Element 30 Detection Circuit 31 Buffer Amplifier 32 High Pass Filter 33 Low Pass Filter 34 Differentiation Circuit 35 Comparator 36 Squib Driver 41 Foaming Filler 42 Squib

Claims (7)

[Claims] 1. A reinforcing side door beam extending in the vehicle front-rear direction in a side door body and having a recess formed in the longitudinal direction, and extending in the recess along the longitudinal direction of the side door beam. And a side surface of the vehicle including a piezoelectric element that outputs a signal according to the deformation amount of the side door beam, and a detection circuit that detects a collision on the side surface of the vehicle based on the output signal of the piezoelectric element. Collision detection device. 2. The side collision detection device for a vehicle according to claim 1, wherein the detection circuit is fixed in the recess of the side door beam. 3. The side collision detection device for a vehicle according to claim 1, wherein the piezoelectric element has flexibility. 4. The side collision detection device for a vehicle according to claim 1, wherein the side door beam has a hollow shape to form the recess. 5. The side collision detection device for a vehicle according to claim 4, wherein the piezoelectric element is installed on a side surface inside the vehicle interior inside the hollow side door beam. 6. The side collision detection device for a vehicle according to claim 4, further comprising a filler that is filled in the hollow inside of the side door beam and fixes the piezoelectric element. 7. The side collision detection device for a vehicle according to claim 4, wherein the side door beam is made of a material having a magnetic shield function.