JPH07190732A - Collision sensor for vehicle - Google Patents

Abstract

PURPOSE:To let the detection of vehicle collision be compatible with the enhancement of ornamental nature. CONSTITUTION:The front bumper 12 of a vehicle is provided with an optical leakage fiber 14. Light is incident on the fiber from a light projection unit 20 located at one end side of the aforesaid fiber 14, and light passing through the fiber 14 arrives at the other end side so as to be detected by a light receiving unit 30 located at the aforesaid end side. Since a part of light which is incident on the fiber 14, leaks, the fiber looks as if the fiber 14 itself emitted light, so that both the visibility and ornamental nature of the vehicle is thereby enhanced. When collision happens to the vehicle, it is often seen that the fiber 14 is ruptured, or is compressed so as to be deformed, the amount of optical leakage is thereby increased, or energy of optical arrival at the light receiving unit 30 is thereby decreased, this constitution thereby allows a collision detection signal to be outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle collision sensor for detecting that a vehicle such as an automobile has collided with another object.

[0002]

2. Description of the Related Art For example, when an automobile collides with an obstacle,
BACKGROUND ART A collision sensor that detects a collision in order to operate a safety device such as an airbag or a seat belt installed in a vehicle or a brake device has been conventionally developed. As an example, for example, the actual Kaihei 2-1108.
"Object contact force detection device" described in Japanese Patent No. 40
There is. This is a structure in which a pressure-sensitive switch which is bent and deformed when a large pressing force is applied to close the contacts is formed in a tape shape, and is arranged inside a urethane bumper of an automatic guided vehicle. With this configuration, when an automated guided vehicle collides with an obstacle,
The urethane bumper is compressed and deformed to actuate the pressure sensitive switch, and thus a collision detection signal is output and sudden braking is applied.

[0003]

By the way, in order to prevent an accident itself or to enhance the decorativeness of a vehicle, for example, it is considered that a bumper portion is made to shine (for example, the actual opening 63). -122139
No.), a certain effect is provided in terms of safety and decorativeness. It would be even more beneficial if the bumper part shines like this and also has a collision sensing function.

However, the above-mentioned actual Kaihei 2-110 is used.
In the structure of the conventional collision detection sensor shown in No. 840 and the like, it is impossible to have both functions, and this point remains as an unsolved problem.

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a vehicle collision sensor capable of reliably detecting a vehicle collision and yet exhibiting excellent effects in terms of safety and decorativeness by emitting light by itself.

[0006]

According to a first aspect of the present invention, there is provided a vehicle collision sensor having a leaky optical fiber at least a part of which is exposed along an outer surface of a vehicle, and one end of the leaky optical fiber. Side light-incident part, a light-receiving part provided at the other end of the leaky optical fiber for receiving light from that fiber, and a collision detection signal output when the amount of light received by this light-receiving part decreases And a detection circuit for

In this case, the light projecting section may be provided with a filter for selecting the wavelength of the light incident on the leaky optical fiber (the invention of claim 2), and these filters may be selected depending on the running condition of the vehicle. It is also possible to adopt a configuration for selectively activating either of them (the invention of claim 3). The leaky optical fiber is composed of a transparent light-transmitting tube and a transparent light-transmitting core filled in the flexible light-transmitting tube and having a refractive index lower than that of the light-transmitting tube. It is also possible (the invention of claim 4).

[0008]

According to the first aspect of the invention, when light is incident on the leaky optical fiber from the light projecting portion, part of the light reaches the light receiving portion and part of the light leaks out of the fiber. Since the leaky optical fiber is exposed along the outside surface of the vehicle, the fiber looks like it emits light from the outside of the vehicle, and the visibility of the vehicle itself becomes significantly high especially in a dark place. Also, a decorative effect can be expected. If a vehicle collides with an obstacle and a strong force is applied to the fiber located on the outer surface of the vehicle, the fiber may break or be deformed such as compressed, causing the light incident from one end of the fiber to reach the other end. It does not arrive or the arrival amount decreases, and the detection circuit operates based on this, and a collision detection signal is output.

If a filter is provided in the light projecting section as in the second aspect of the invention, the leaky optical fiber can emit light in a desired color. Further, as in the third aspect of the invention, a plurality of types of filters are provided, By selectively activating them according to the running state of the vehicle, the running state of the vehicle can be visually recognized from the outside by the color of the light emitted by the leaky optical fiber. Further, when the leaky optical fiber is configured as in the invention of claim 4, since the fiber itself is highly flexible, the optical fiber itself follows the outer surface shape when arranged along the outer surface of the vehicle. And the degree of freedom in arrangement increases.

[0010]

As described above, according to the present invention, the collision of the vehicle can be surely detected, but the vehicle itself emits light, so that the visibility of the vehicle is enhanced and there is an effect on safety, and the decoration is also improved. Effect can be expected. Further, in particular, according to the invention of claim 2, since the emission color of the leaky optical fiber can be made a desired color, the value is further enhanced in terms of decorativeness. In the invention of claim 4, the vehicle travels from the outside. The condition can be confirmed and it is more effective in terms of safety. Further, according to the configuration of claim 3, since the leaky optical fiber is flexible, the degree of freedom in arrangement is increased and it becomes easier to use.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> This embodiment is an example in which the collision sensor of the present invention is applied to a front collision detection system in a passenger vehicle. As shown in FIG. 1, a front bumper 12 integrally formed of polyurethane is attached to the front of the vehicle body 11, and a fiber storage groove 13 is formed on the outer surface of the front bumper 12 from the front of the vehicle to both left and right sides. Formed (see FIG. 2). A leaky optical fiber 14 is stored in the entire fiber storage groove 13 with a part thereof exposed as shown in FIG. 2, and both ends thereof are introduced into the engine room of the vehicle.

The leaky optical fiber 14 described above is manufactured as follows. That is, a transparent polyvinyl chloride tube is used as the light-transmitting tube 14a having flexibility (for example, outer diameter 3 mm, inner diameter 2 mm), and a light-transmitting liquid silicone elastomer is filled therein and cured. The cured silicone elastomer becomes the flexible light-transmitting core 14b, and together with the light-transmitting tube 14a, the leaky optical fiber 14 has a soft and highly flexible structure. The leaky optical fiber 14 is shown in FIG.
As shown in FIG. 2, the inner transparent core 14b has a two-layer structure in which the transparent tube 14a surrounds it. However, contrary to a normal optical fiber used as an optical waveguide for communication,
Since the refractive index of light is lower in the silicone elastomer located inside than in the polyvinyl chloride located outside, total reflection does not occur at the boundary from the light-transmitting core 14b to the light-transmitting tube 14a, and the light-transmitting property is low. Light easily enters the inside of the translucent tube 14a from the inside of the core 14b, and a considerable amount of light leaks out from there.

One end of the leaky optical fiber 14 is introduced into a light projecting unit 20 provided in the engine room. As shown in FIG. 4, an incandescent lamp 22 such as a halogen lamp or a xenon lamp having a reflecting mirror 21 is provided in the light projecting unit 20, and is coaxial with the optical axis of the reflecting mirror 21. Thus, the end portion of the leaky optical fiber 14 is held by the holder 23. The holder 23 is provided with a condenser lens 24 coaxially with the fiber 14 so that the light from the lamp 22 leaks out from the optical fiber 1.
It is designed to be incident on 4 in parallel. Also, the holder 2
A circular filter plate 25 is rotatably provided between the reflector 3 and the reflecting mirror 21 around an axis 26 off the optical axes of the reflecting mirror 21 and the fiber 14, and four types are formed on the filter plate 25. Circular filters 25a-25d are selectively positioned between the lamp 22 and the fiber 14. In addition, in FIG. 5, each of the filters 25a to 25a
In order to distinguish 5d, those portions are displayed with different diagonal lines. In each of the filters 25a to 25d, the wavelength of the incident light from the lamp 22 to the leaky optical fiber 14 is selected, and depending on which of the filters 25a to 25d corresponds, light of a specific wavelength, that is, a specific color is leaked into the leaky optical fiber 14. Incident on the inside. Further, the shaft 26 of the filter plate 25 is rotated by the motor 27 at a predetermined constant speed, so that the color of the light incident on the fiber 14 repeatedly changes at a predetermined cycle. These configurations configure a light projecting unit that causes light to enter one end of the leaky optical fiber 14.

On the other hand, the other end of the leaky optical fiber 14 is introduced into the light receiving unit 30 also provided in the engine room, and the light receiving portion as shown in FIG. 6 is provided therein. That is, the other end of the fiber 14 is inserted and held in the cylindrical holder 31, and the phototransistor 32 is held on the opposite side of the holder 31 with the light-receiving surface facing the end face of the fiber 14. The holder 3 is provided between the phototransistor 32 and the end of the fiber 14.
A condenser lens 34 is fixed via 3 to guide the light emitted from the end of the fiber 14 to the phototransistor 32.

The phototransistor 32 is connected to the detection circuit 40 as shown in FIG. The comparator 41 compares the reference voltage divided by the resistors 42 and 43 with the emitter voltage of the phototransistor 32.
When the amount of incident light on 2 decreases and the emitter voltage decreases,
The output terminal of the comparator 41 is pulled up to a high level and the collision detection signal S is output. In this embodiment, the collision detection signal S is applied to an airbag operating circuit (not shown) to activate the inflator of the airbag.

Next, the operation of this embodiment will be described.
When a predetermined switch in the vehicle is operated, the light emitting unit 20
The lamp 22 is turned on and the motor 27 is rotated. By the rotation of the motor 27, the four kinds of filters 25a to 25d of the filter plate 25 are sequentially interposed between the lamp 22 and the end portion of the leaky optical fiber 14. At this time, since light does not pass through the boundary portions of the filters 25a to 25d, the light of four colors sequentially enters the leaky optical fiber 14 while blinking at a predetermined cycle.

The light incident on the fiber 14 propagates through the fiber 14, but the transparent tube 14a of the fiber 14 has a larger refractive index than the transparent core 14b.
Without being confined in the translucent core 14b, it gradually leaks to the outside while being transmitted to the other end side. Therefore, when the leaky optical fiber 14 is observed from the outside, the fiber 14 itself looks bright over the entire area, the vehicle can be easily visually recognized even at night, and the decorative function is exerted. Moreover, in particular, in this embodiment, since the filter plate 25 is rotated so that the light of four colors is sequentially incident on the fiber 14, the front bumper 12 portion blinks in various colors, so that the vehicle can be visually recognized. In addition to improved safety and safety, decorativeness is also enhanced.

On the other hand, a part of the light incident on the fiber 14 reaches the other end of the fiber 14 and the light receiving unit 30
It is incident on the inside of the phototransistor 32. If there is no change in the state of the leaky optical fiber 14, the amount of light reaching the phototransistor 32 does not change, so the output of the comparator 41 remains at a low level.

However, should the vehicle collide with an obstacle, a large force acts on the leaky optical fiber 14 mounted on the front bumper 12 and it is strongly compressed.
It breaks. If the fiber 14 breaks, of course,
Since the light from the light projecting unit 20 does not reach the light receiving unit 30, the light does not enter the phototransistor 32, and the comparator 41 of the detection circuit 40 inverts to output the high-level collision detection signal S. Will be done. As a result, the inflator of the airbag operates to inflate the airbag, thus ensuring the safety of the occupant.

Even if the leaky optical fiber 14 is not broken, the detection circuit 40 similarly outputs the collision detection signal S. That is, when light is transmitted from one end side of the leaky optical fiber 14 toward the other end side, if the fiber 14 is pressed and crushed, the leaked light greatly increases. The situation is shown in the graph of FIG. In this graph, the middle portion of the linearly arranged leaky optical fiber 14 is sandwiched between resin plates, and the pressure is plotted on the horizontal axis.
The attenuation of the fiber 14 with respect to the incident light is measured and displayed in units of decibel on the vertical axis. From this point as well, it can be seen that when the leaky optical fiber 14 receives lateral pressure and is compressed, the transmitted light is greatly attenuated. Therefore, in the present embodiment, in the case where a vehicle collision accident occurs as described above, even if the obstacle does not directly collide with the leaky optical fiber 14 and the breakage thereof does not occur, the fiber 1 is not broken.
Since the amount of incident light on the phototransistor 32 is greatly reduced due to the deformation such as the abnormal bending and the compression of 4, the collision detection signal S is output from the comparator 41 of the detection circuit 40, the airbag is inflated, and the safety of the occupant is secured. Will be done.

As described above, according to this embodiment, since the leaky optical fiber 14 mounted on the front bumper 12 emits light by itself, the vehicle can be easily visually recognized even at night, the safety is enhanced, and the decorative function is provided. Also exerts. Moreover, particularly in the present embodiment, the front bumper 12 portion blinks while changing to various colors, so that not only the visibility of the vehicle is improved, but also
The decorativeness is also higher. In addition to such a visual effect, the leakage optical fiber 14 should not be damaged if the vehicle crashes and the front bumper 12 is impacted.
It is possible to immediately output the collision detection signal S from the detection circuit 40 on the basis of the breakage or compression, and also has a collision detection function.

<Second Embodiment> FIGS. 9 and 10 show a second embodiment of the present invention. In this embodiment, the same leaky optical fiber 14 as that of the first embodiment is mounted on the side portion of the vehicle body 11 so that the decorativeness of the side surface of the vehicle can be improved and the side collision can be detected at the same time. Therefore, the configurations of the leaky optical fiber 14, the light projecting unit 20, the light receiving unit 30, and the detection circuit 40 are the same as those in the first embodiment, and a duplicate description will be omitted and different points will be described (note that the same portions are the same. With a sign).

In this embodiment, the leaky optical fiber 14 is
It is mounted so as to extend in a straight line in the front-rear direction to the fender portion, the front door portion, the rear door portion, and the rear trunk portion on both left and right sides of the vehicle (only on the left side of the vehicle in FIG. 9). Four plastic holders 50 are used for the mounting. This holder 50 has a long strip shape, and as shown in FIG. 10, a fiber housing groove 51 is continuously formed on the outer surface along the longitudinal direction, and the opposite side surface is intermittently formed on the vehicle body outer plate. It is fixed by various bolts (not shown) (it can be fixed with an adhesive). The leaky optical fiber 14 is fitted and fixed in the fiber housing groove 51 with half of the fiber exposed, and both ends of the fiber 14 are introduced into the body. A light projecting unit 20 and a light receiving unit 30 are connected to both ends of each fiber 14, and light of four colors is sequentially incident on the leaky optical fiber 14 from the light projecting unit 20 in the same manner as in the above-described embodiment. At, the light transmitted through the leaky optical fiber 14 is detected.

Also in this embodiment, the leaky optical fibers 14 provided on both the left and right sides of the vehicle shine in various colors, the visibility of the vehicle is improved and the safety is improved.
Moreover, decorativeness is also enhanced. If a collision occurs on the side surface of the vehicle, the amount of transmitted light decreases due to the breakage or deformation of the fiber 14 as in the above embodiment, and the collision detection signal from the detection circuit 40 is thereby generated. S will be output immediately.

The present invention is not limited to the above-mentioned embodiments, but can be carried out in the following modes, for example.

(A) In both of the above embodiments, the rotating filter plate 25 is provided in the light projecting portion so that the wavelength of the light incident on the leaky optical fiber 14 is periodically made different, but the invention is not limited to this. For example, as shown in FIG. 11, the filter may be omitted, and the white light from the lamp 22 may be condensed by the reflecting mirror 21 and may be incident from the end of the leaky optical fiber 14 through the condenser lens 24. Although not shown, a filter may be fixedly provided, and these configurations are of course included in the concept of the “projection unit for making light incident on one end side of the leaky optical fiber” in the present invention.

(B) Even if a plurality of types of filters are provided in the light projecting section and the colors of light incident on the leaky optical fiber are made different, one of the filters is selectively selected according to the running state of the vehicle. Alternatively, the light emission color of the leaky optical fiber may be changed according to the running state of the vehicle.
In this case, for example, a configuration may be adopted in which the traveling speed of the vehicle is detected and the emission color of the leaky optical fiber is changed according to the traveling speed, and when traveling at a normal speed, for example, it is colored in green, and the vehicle brake is applied. For example, the configuration may be such that, for example, red color is generated when in the operating state.

(C) Further, in the light projecting portion, a laser diode or a light emitting diode may be used without necessarily using an incandescent lamp. For example, when a laser diode is used, light is emitted in one direction. Therefore, as shown in FIG. 12, one end of the leaky optical fiber 14 is inserted and fixed to one end of a cylindrical holder 61, and the other end is fixed. A simple structure in which the laser diode 62 is inserted and fixed at the end can be adopted.

(D) The leaky optical fiber is not limited to the combination of the polyvinyl chloride tube and the silicone elastomer as in the above embodiments, but the material of the transparent tube is polyethylene, polyester, silicon rubber, Polyvinyl chloride, polyvinyl fluoride, polyvinylidene fluoride, etc. can be used, and as the material of the translucent core, a thermoelastomer or a liquid cured product can be used. In addition, the use of a flexible material for both the light-transmitting tube and the light-transmitting core resin as in the above-described embodiment has the advantage that the leaky optical fiber is easily bent and the degree of freedom in shape is increased. However, it is not always necessary to do so, and a hard material such as a hard acrylic resin, a polycarbonate resin, or glass may be used as the translucent core resin. Further, the fiber having a single-layer structure of a translucent material may not necessarily be a two-layer structure of a translucent tube and a translucent core resin, and in short, while leaking light from one end side to the other end side. If it can be derived, it can be used as the leaky optical fiber of the present invention.

(E) Further, as the leaky optical fiber, one in which fine particles for light scattering are mixed in the fiber (in a transparent tube or a transparent core resin in the case of a two-layer structure) is also used. As a result, the amount of light leakage increases, so that the emission brightness of the fiber increases. Further, in the case of this configuration, if the distribution of the fine particles to be mixed is made to be a gradient density distribution in which the density becomes lower toward the incident end side of the light, the amount of light leakage of the fiber is made uniform along the length direction and the entire fiber is made uniform. It can emit light.

In addition, the present invention is not limited to the passenger cars as shown in the embodiments, but may be applied to a baggage carrying vehicle such as an unmanned guided vehicle with various modifications within the scope not departing from the gist. can do.

[Brief description of drawings]

FIG. 1 is a perspective view of a vehicle showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a bumper

FIG. 3 is a perspective view of a leaky optical fiber, a part of which is shown in section.

FIG. 4 is a sectional view of a light projecting portion.

FIG. 5 is a front view of the filter plate.

FIG. 6 is a sectional view of a light receiving portion.

FIG. 7 is a circuit diagram of a detection circuit.

FIG. 8: Optical attenuation curve of leaky optical fiber

FIG. 9 is a perspective view of a vehicle showing a second embodiment of the present invention.

FIG. 10 is a cross-sectional view showing an attached state of a leaky optical fiber according to a second embodiment.

FIG. 11 is a sectional view showing a modified example of the light projecting unit.

FIG. 12 is a cross-sectional view showing another modification of the light projecting section.

[Explanation of symbols]

 12 ... Front bumper 14 ... Leakage optical fiber 14a ... Translucent tube 14b ... Translucent core resin 20 ... Light projecting unit 25 ... Filter plate 25a-25d ... Filter 30 ... Light receiving unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masato Kawamura 1-14 Nishisuehiro-cho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd.

Claims (4)

[Claims] 1. A leaky optical fiber which is provided so that at least a part thereof is exposed along an outer surface of a vehicle, a light projecting section which allows light to enter one end side of the leaky optical fiber, and the other leaky optical fiber. A vehicle collision sensor comprising a light receiving portion provided on an end side for receiving light from the fiber, and a detection circuit for outputting a collision detection signal when the amount of light received by the light receiving portion decreases. 2. The vehicle collision sensor according to claim 1, wherein the light projecting portion is provided with a filter for selecting a wavelength of light incident on the leaky optical fiber. 3. The vehicle collision sensor according to claim 2, wherein the light projecting unit is provided with a plurality of types of filters, and these filters are selectively activated according to a running state of the vehicle. 4. The leaky optical fiber comprises a light-transmitting tube having flexibility, and a light-transmitting tube filled with the light-transmitting tube having flexibility and having a refractive index lower than that of the light-transmitting tube. The collision sensor for a vehicle according to any one of claims 1 to 3, wherein the collision sensor is formed of a flexible core.