JP4038897B2 - Ultrasonic sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic sensor, and more particularly to an ultrasonic sensor for detecting an obstacle mounted on a vehicle.
[0002]
[Prior art]
As an obstacle detecting ultrasonic sensor mounted on a vehicle, one that performs transmission of an ultrasonic signal and reception of a reflected wave from an obstacle with a single vibrator is generally used, as shown in FIGS. Thus, it is assembled | attached to the bumper 10 part in a vehicle. And in order to give directivity, the front end surface of the vibrator 2 housed in the housing 1 is positioned in the rear end portion of the horn 3. In the figure, 6 is a retainer for attachment, 7 is a connecting wire, and 8 is a retainer engaging portion.
[0003]
Here, when the obstacle is detected by being mounted on the vehicle, the horn 3 is disposed in an exposed state, and therefore, since there is intrusion of rainwater, a drain hole 5 is provided in the vicinity of the vibrator 2. Provided.
[0004]
[Problems to be solved by the invention]
By the way, the presence of the drain hole 5 means that the ultrasonic wave leaks out of the horn 3 from here, and the ultrasonic wave reflected inside the bumper 10 returns to the vibrator 2 through the drain hole 5 again. . This causes malfunctions when transmission and reception are performed by the single vibrator 2.
[0005]
That is, in the case where the transmission and reception of ultrasonic waves are performed by the single vibrator 2, the transmission of ultrasonic waves is performed at intervals and the reception is performed during transmission. At this time, the transmission is stopped. Since the vibration of the vibrator 2 continues for a while after that, a period from when the vibration is attenuated until the next transmission is started is defined as a reception period t, and a reflected wave having a predetermined level or more within the reception period t. when is returned, but it outputs an alarm is regarded as an obstacle, the reception period, as reflected waves of ultrasonic signals emitted to the outside through the drain hole 5 is shown in FIG. 12 t In some cases, the vibrator 2 is reached.
[0006]
The present invention has been made in view of these points, and an object of the present invention is to provide an ultrasonic sensor capable of preventing malfunction due to the presence of a drain hole.
[0007]
[Means for Solving the Problems]
Therefore, the present invention provides an ultrasonic sensor in which a water drainage hole is provided in a housing or a horn containing a vibrator, and a reflecting plate that covers the outer surface side of the water drainage hole at an interval is connected to the housing or the horn. provided with as being opened laterally, ultrasound normal direction in the reflector portion facing in a direction other than the drain hole to face the drain hole, has leaked to the outside through the drain hole It is characterized in that the reflection direction of the signal on the reflection plate is a direction other than the drain hole .
[0008]
The ultrasonic signal leaked to the outside through the drain hole is attenuated while repeatedly reflecting between the reflector and the outer surface of the housing, and even if the reflection of the ultrasonic signal returns to the vibrator through the drain hole again, Levels are getting smaller.
[0009]
The reflecting plate is preferably detachable from the housing, and it is also preferable that a sound absorbing material is attached to the inner surface of the reflecting plate, or the inner surface of the reflecting plate is a diffusely reflecting surface having a number of irregularities.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on an example of an embodiment. The ultrasonic sensor shown in FIG. 1 to FIG. 3 is similar to the conventional example in the vibration 1 for transmitting and receiving in the housing 1 provided with the horn 3. The child 2 is housed and is attached to the inside of a bumper 10 of an automobile by a retainer engaging portion 8 and a retainer 6 provided on the outer surface of the horn 3. The vibrator 2 is disposed so as to be located at the base of the horn 3, and a drain hole 5 is provided at a position near the front side of the vibrator 2 at the lower part of the housing 1.
[0011]
A reflector 4 having a V-shaped cross section is disposed below the drain hole 5 for discharging rainwater that has entered the horn 3. The reflecting plate 4 having one inclined side located directly under the drain hole 5 and both front and rear ends connected to the housing 1 and the horn 3 is in a state where the left and right directions are open. Water from the hole 5 is discharged without being disturbed by the reflector 4.
[0012]
The ultrasonic signal leaked to the outside from the drain hole 5 is applied to the other inclined side or the outer surface of the housing 1 with respect to one inclined side in which the direction of the normal line in the reflector 4 is directed to a direction other than the drain hole 5. The light is reflected toward and further reflected here, and is also directed toward the inclined side and the housing 1. The ultrasonic signal is repeatedly reflected between the reflecting plate 4 and the housing 1. Therefore, even if there is an ultrasonic signal (reflected wave) returning to the vibrator 2 through the drain hole 5, the reflection is repeated. The signal intensity level is greatly reduced due to the attenuation due to the signal intensity. Therefore, even if the reflected wave through the drain hole 5 reaches the vibrator 2 during the reception period t, the signal intensity is lower than the level at which an alarm is output. ing. Thus, no false alarms will occur.
[0013]
4 to 6, the side plates 40, 40 provided on both sides of the reflecting plate 4 having a V-shaped cross section are provided with engaging holes 41 that engage with the locking projections 11 provided on both side surfaces of the housing 1. As shown in FIG. The reflector 4 is detachable from the housing 1. The reflection plate 4 can be attached to the housing 1 as necessary, and the reflection plate 4 is commonly used by providing a common locking projection 11 for various ultrasonic sensors. It is something that can be done.
[0014]
The reflecting plate 4 only needs to reflect an ultrasonic signal leaked to the outside through the drain hole 5 in a direction other than the drain hole 5, and therefore has a circular arc shape as shown in FIG. Alternatively, the shape may be a combination of inclined sides and arc sides.
[0015]
Further, as shown in FIG. 8, if a sound absorbing material 43 is attached on the inner surface side, the ultrasonic signal can be further attenuated. As shown in FIG. 9, even if a large number of projections and depressions 44 are provided on the inner surface of the reflector 4 so that the ultrasonic signal is irregularly reflected, the attenuation amount of the ultrasonic signal can still be increased, and a malfunction occurs. Can be effectively prevented. .
[0016]
【The invention's effect】
As described above, in the present invention, the reflector plate that covers the outer surface side of the drain hole at an interval is provided as both ends are connected to the housing and the horn and the sides are open. The part where the direction of the line is directed to the direction other than the drain hole is made to face the drain hole, and the reflection direction of the ultrasonic signal leaked to the outside through the drain hole is the direction other than the drain hole. Therefore, the ultrasonic signal leaked to the outside through the drain hole is directed to the direction other than the drain hole due to reflection by the reflector, and attenuates while repeatedly reflecting between the reflector and the outer surface of the housing. Even if the reflection of the ultrasonic signal returns to the vibrator through the drain hole again, the signal level is reduced, so that the occurrence of malfunction can be prevented.
[0017]
If the reflector is detachable from the housing, the reflector can be attached as necessary, and the reflector can be shared by various ultrasonic sensors. If a sound-absorbing material is attached to the reflector, or if the inner surface of the reflector is an irregular reflection surface with many irregularities, the attenuation amount of the ultrasonic signal can be further increased, so that the occurrence of malfunction is more effectively prevented. be able to.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the above.
FIG. 3 is a side view of the above.
FIG. 4 is a side view of another example of the above.
FIGS. 5A, 5B, and 5C are a plan view, a side view, and a front view of the above-described reflector.
FIG. 6 is a partial sectional view of the above.
7A, 7B, and 7C are a plan view, a side view, and a front view, respectively, of another example of the reflector.
FIG. 8 is a partial side view of another example.
FIG. 9 is a partial side view of a different example.
FIG. 10 is a side view of a conventional example.
FIG. 11 is a cross-sectional view of the above.
FIG. 12 is an explanatory diagram of transmission and reception of an ultrasonic signal.
[Explanation of symbols]
1 Housing 2 Vibrator 3 Horn 4 Reflector 5 Water drain hole

Claims (4)

In an ultrasonic sensor in which a water drainage hole is provided in a housing or horn containing a vibrator, a reflector that covers the outer surface side of the water drainage hole with a gap is connected to the housing or the horn and the sides are open. The portion of the reflector that has a normal direction facing the direction other than the drain hole is opposed to the drain hole, and the ultrasonic signal leaked to the outside through the drain hole An ultrasonic sensor characterized in that the reflection direction is a direction other than the drain hole .   2. The ultrasonic sensor according to claim 1, wherein the reflector is detachable from the housing.   The ultrasonic sensor according to claim 1 or 2, wherein a sound absorbing material is attached to the inner surface of the reflector.   3. The ultrasonic sensor according to claim 1, wherein the reflecting plate has a diffusely reflecting surface having a large number of irregularities on the inner surface.

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