JP3651475B2 - Ultrasonic sensor and ultrasonic transducer used for the ultrasonic sensor - Google Patents

Description

  The present invention relates to an ultrasonic sensor having an ultrasonic transducer, and the ultrasonic sensor may be used, for example, in a vehicle obstacle detection device that is attached to a vehicle bumper and detects an obstacle at the rear or corner of the vehicle. it can.

  Conventionally, in an obstacle detection device for a vehicle, an ultrasonic sensor is attached to a bumper of the vehicle, an ultrasonic wave is transmitted to the rear or corner of the vehicle, and an ultrasonic wave reflected by the obstacle is received to detect the obstacle. I am doing so. Here, the ultrasonic sensor is configured by assembling an ultrasonic transducer in a case. This ultrasonic vibrator has a circular vibration surface, and when a voltage is applied, it vibrates due to the piezoelectric effect and transmits an ultrasonic signal, and when it receives a reflection of this transmitted ultrasonic signal, it receives a voltage due to the inverse piezoelectric effect. The directivity is equal in the horizontal direction and the vertical direction.

  Also, when detecting obstacles outside the vehicle, a long oval opening in the vertical direction is installed in the case that houses the ultrasonic transducer in order to increase the horizontal detection area without detecting the ground as an obstacle. Is formed, and an ultrasonic transducer is provided in the back of the opening to make the directivity of the ultrasonic sensor narrow in the vertical direction and wide in the horizontal direction.

  As described above, in the conventional ultrasonic sensor, the ultrasonic transducer having the same directivity in the horizontal direction and the vertical direction is used, and the shape of the opening of the case is devised to obtain a desired directivity characteristic as the ultrasonic sensor. Trying to get.

  On the other hand, in recent years, ultrasonic transducers having different directivities in the horizontal direction and the vertical direction have been proposed. In this ultrasonic transducer, the directivity in the horizontal direction and the vertical direction are made different by making the vibration surface into an oval shape.

  However, in this type of ultrasonic vibrator, the vibration surface is preferably circular, and when the vibration surface is circular, the ultrasonic vibrator itself is different in the horizontal and vertical directions. Due to the directivity, when the ultrasonic transducer is assembled in the case, there is a possibility that the horizontal direction and the vertical direction are mistakenly attached.

  The present invention has been made in view of the above-mentioned problems. When an ultrasonic vibrator having a circular vibration surface and having different directivities in the horizontal direction and the vertical direction is used, the assembly direction should not be mistaken. For the purpose.

To achieve the above object, in the ultrasonic sensor according to claim 1, a hollow housing (11) having a vibration part (11a) whose outer surface is a circular vibration surface (11b); An ultrasonic transducer including a piezoelectric element (12) attached to the inner surface of the vibrating portion of the housing and a circular opening surface (22a), and the ultrasonic transducer from the opening surface An ultrasonic sensor including a case that is inserted and assembled therein, wherein the case has a shape (26) in which the vertical direction and the horizontal direction of the ultrasonic sensor can be identified, and the ultrasonic transducer The inner space (13) of the housing is different in diameter in the vertical and horizontal directions, and has a shape that makes the directivity of the ultrasonic vibrator different in the horizontal direction and the vertical direction. Vertical Is characterized in that the identification means (17, 18) are formed for identifying and.
Further, in the ultrasonic vibrator according to claim 7, a hollow housing (11) having a vibration part (11a) whose outer surface is a circular vibration surface (11b), and the housing in the housing. An ultrasonic vibrator including a piezoelectric element (12) attached to the inner surface of the vibration unit, wherein the ultrasonic vibrator has a shape (26) and a circular shape that can distinguish the vertical direction and the horizontal direction. Is inserted into the case and assembled from the opening surface, and the internal space (13) of the housing has the directivity of the ultrasonic transducer in the horizontal direction and the vertical direction. The identification means (17, 18) for identifying the horizontal direction and the vertical direction are formed as outer shapes on the side surface of the housing. The

  According to the present invention, since the horizontal direction and the vertical direction of the ultrasonic transducer can be identified, when assembling the ultrasonic transducer inside the case, the assembly direction should not be mistaken. Can do.

The invention described in claim 2 and claim 8 is characterized in that the identification means is a flat portion formed on a side surface of the housing.

The invention according to claim 3 and claim 9 is characterized in that the flat portion is formed on both side surfaces of the housing. In this case, as in the inventions of the fourth and tenth aspects, the vertical direction of the flat portion formed on both side surfaces of the housing can exhibit directivity in the vertical direction.

  The invention described in claim 5 is characterized in that the shape of the case that can be identified is a flat portion formed on both side surfaces of the case.

  According to a sixth aspect of the present invention, the case is inserted into and attached to a mounting hole (31) formed in a bumper of a vehicle, and the mounting hole of the bumper is long so as to fit a flat portion of the case. It is characterized by being formed in a circular shape. In this case, when attaching the ultrasonic sensor to the bumper of the vehicle, it is possible to prevent the attachment direction from being mistaken.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments shown in the drawings will be described below. FIG. 1 shows the configuration of an ultrasonic transducer according to an embodiment of the present invention. (A) is a front view of an ultrasonic transducer | vibrator, (b) is a right view, (c) is a back view. This ultrasonic transducer is configured by filling a hollow housing 11 with a filler 16, and a side cross-sectional view and a rear view of the ultrasonic transducer with the filler 16 removed are shown in FIG. Shown in (e). FIG. 1D is a cross-sectional view taken along the line AA in FIG.

  The ultrasonic transducer has a piezoelectric element 12 in a conductive housing 11. As shown in FIG. 1D, an internal space 13 is formed inside the housing 11, and the piezoelectric element 12 is attached to the inner surface of the vibration part 11 a in the housing 11. The outer surface of the vibration part 11a, that is, the vibration surface 11b has a circular shape.

  One end of a lead 15 is soldered to the piezoelectric element 12. The housing 11 has a notch 14 formed on the inner side surface, and the other end of the lead 15 is soldered to the notch 14. As a result, an AC signal can be applied to both ends of the piezoelectric element 12 via the housing 11. As shown in FIG. 1E, the internal space 13 has a shape with different diameters (vertical shape with rounded corners) when viewed from the back side. With the internal space 13 having such a shape, directivity can be made different between the horizontal direction and the vertical direction. FIG. 2 shows the directivity characteristics of this ultrasonic transducer. It has wider directivity in the horizontal direction than in the vertical direction. In FIG. 1, the vertical direction is a vertical direction with a narrow directivity, and the horizontal direction is a horizontal direction with a wide directivity.

  After the lead 15 is soldered, the internal space 13 is filled with a felt and silicon filler 16 in order from the piezoelectric element 12 side. In addition, as shown in FIGS. 1A, 1 </ b> B, and 1 </ b> C, the ultrasonic transducer has flat portions 17 having flat surfaces formed on both side surfaces of the housing 11. With this plane portion 17, it can be identified that the vertical direction in FIG. 1A has directivity in the vertical direction and the horizontal direction has directivity in the horizontal direction.

  FIG. 3 shows a state in which an ultrasonic sensor having the ultrasonic transducer shown in FIG. 1 (indicated by reference numeral 10 in FIG. 3) is attached to a vehicle bumper. (A) is a front view, (b) is a side sectional view. The ultrasonic sensor includes an ultrasonic transducer 10, a processing circuit 21 that applies a driving voltage for generating ultrasonic waves to the ultrasonic transducer 10 and processes a voltage generated from the ultrasonic transducer 10 by a back electromotive force effect, and Is assembled in a case 22 made of resin.

  In the case 22, a vibration isolating member (silicon rubber) 23 that prevents vibration transmission from the ultrasonic vibrator 10 to the case 22 is provided around the ultrasonic vibrator 10. Further, a moisture-proof silicon resin 24 is filled in the rear portion of the processing circuit 21. The processing circuit 21 is connected to a controller (not shown) via the harness 25, and the controller detects obstacles at the rear or corner of the vehicle.

  The case 22 has a circular opening surface 22a, and the ultrasonic transducer 10 and the vibration isolation member 23 are inserted and assembled in the right direction in the drawing from the opening surface 22a side. The case 22 has a protrusion 22b, which restricts the insertion position of the ultrasonic transducer 10 and the vibration isolator 23. By this assembly, the opening surface 22a of the case 22 and the vibration surface 11b of the ultrasonic transducer 10 are positioned on substantially the same surface, and the respective outer shapes are in a concentric relationship.

  In addition, the lead 15 of the ultrasonic transducer 10 is soldered to the processing circuit 21 and electrically connected to the processing circuit 21. Then, the processing circuit 21 is inserted from the back side of the case 22 in the left direction in the figure, and thereafter, the moisture-proof silicone resin 24 is filled in the rear portion of the case 22. In this way, the ultrasonic sensor 20 shown in FIG. 3 is assembled.

  Here, since the ultrasonic transducer 10 has different directivity in the horizontal direction and the vertical direction as described above, when the ultrasonic transducer 10 is assembled in the case 22, the ultrasonic transducer 10 is assembled upside down. However, if the top and bottom and left and right are assembled in reverse, the desired directivity cannot be obtained. For this reason, as shown in FIG. 1, the ultrasonic transducer 10 is formed with flat portions 17 on both side surfaces of the housing 11, and the ultrasonic waves so that the flat portions 17 are positioned up and down in FIG. 3. By assembling the vibrator 10 in the case 22, it is possible to prevent a mistake in the assembling direction of the ultrasonic vibrator 10. Therefore, the flat surface portion 17 formed on the ultrasonic transducer 10 functions as an identification unit for identifying the horizontal direction and the vertical direction, or an alignment unit when the ultrasonic transducer 10 is assembled.

  In addition, when the ultrasonic sensor 20 is attached to the bumper of the vehicle, it is necessary to prevent the ultrasonic sensor 20 from being mistaken for the top and bottom and the left and right. For this reason, as shown in FIG. 4, an oval mounting hole 31 is provided in the bumper 30 of the vehicle, and the case 22 of the ultrasonic sensor 20 is fitted in the case 22 of FIG. As shown in the perspective view of a) and the back view of FIG. 5B, flat portions 26 having flat surfaces are formed on both side surfaces.

Therefore, by inserting the case 22 of the ultrasonic sensor 20 into the mounting hole 31 formed in the bumper 30 of the vehicle, the ultrasonic sensor 20 can be attached to the bumper of the vehicle without making a mistake in the upper and lower sides and the left and right. This makes it possible to widen the directivity of the ultrasonic sensor 20 in the horizontal direction and narrow in the vertical direction when detecting an obstacle at the rear of the vehicle or at the corner, and obtain desired directivity characteristics.

  In the above-described embodiment, the vibration surface 11b of the ultrasonic transducer 10 is substantially the same surface as the opening surface 22a of the case 22 in the ultrasonic sensor 20, and the outer shape is concentric. It is located. In the conventional ultrasonic sensor, since the ultrasonic transducer is provided at the back of the opening, when the ultrasonic sensor is attached to the bumper of the vehicle, it looks like a hole is opened in the bumper. However, according to the above-described embodiment, the ultrasonic transducer 10 is configured to block the opening of the ultrasonic sensor 20. Therefore, the appearance of the ultrasonic sensor 20 can be improved, and foreign matters can be prevented from entering the case 22.

  In the above-described embodiment, the outer shape for identifying the horizontal direction and the vertical direction of the ultrasonic transducer 10 is shown as one in which the planar portions 17 are formed on both side surfaces of the ultrasonic transducer 10. Various other shapes such as a shape in which one flat surface portion 17 is provided on the side surface as shown in FIG. 6 or a shape in which one protrusion portion 18 is formed on the side surface as shown in FIG. 6 and 7, (a) is a front view and (b) is a right side view.

  In addition, the ultrasonic sensor case 21 may be configured to have a shape other than the above-described plane portion 26 as long as it has an outer shape that can identify the horizontal direction and the vertical direction of the ultrasonic sensor.

It is a figure which shows the structure of the ultrasonic transducer | vibrator which concerns on one Embodiment of this invention. It is a figure which shows the directional characteristic of the ultrasonic transducer | vibrator shown in FIG. It is a figure which shows the state which attached the ultrasonic sensor which has an ultrasonic transducer | vibrator shown in FIG. 1 to the bumper of a vehicle. It is a figure which shows the state in which the attachment hole for attaching an ultrasonic sensor to the bumper of a vehicle is formed. It is a figure which shows the external appearance structure of an ultrasonic sensor. It is a figure which shows other embodiment of an ultrasonic transducer | vibrator. It is a figure which shows other embodiment of an ultrasonic transducer | vibrator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Ultrasonic vibrator, 11 ... Housing, 11b ... Vibration surface, 12 ... Piezoelectric element, 13 ... Internal space, 17 ... Planar part formed in housing 11, 20 ... Ultrasonic sensor, 21 ... Processing circuit, 22 ... Case , 22a... Opening surface, 26...

Claims (10)

A hollow housing (11) having a vibrating portion (11a) whose outer surface is a circular vibrating surface (11b), and a piezoelectric element (12) attached to the inner surface of the vibrating portion in this housing An ultrasonic transducer consisting of
An ultrasonic sensor having a circular opening surface (22a), and a case in which the ultrasonic vibrator is inserted from the opening surface and assembled therein;
The case has a shape (26) in which the vertical direction and the horizontal direction of the ultrasonic sensor can be identified,
The inner space (13) of the housing of the ultrasonic vibrator has different shapes in length and width, and has a shape that makes the directivity of the ultrasonic vibrator different in the horizontal direction and the vertical direction,
An ultrasonic sensor characterized in that identification means (17, 18) for identifying the horizontal direction and the vertical direction is formed in the housing. The ultrasonic sensor according to claim 1, wherein the identification unit is a flat portion formed on a side surface of the housing. The ultrasonic sensor according to claim 2, wherein the flat portion is formed on both side surfaces of the housing. The ultrasonic sensor according to claim 3, wherein the vertical direction of the flat portion formed on both side surfaces of the housing shows the directivity in the vertical direction. The ultrasonic sensor according to claim 1, wherein the case can be identified by flat portions formed on both side surfaces of the case. The case is inserted and attached to a mounting hole (31) formed in a bumper of the vehicle, and the mounting hole of the bumper is formed in an oval shape so as to fit the flat portion of the case. The ultrasonic sensor according to claim 5, wherein: A hollow housing (11) having a vibrating portion (11a) whose outer surface is a circular vibrating surface (11b), and a piezoelectric element (12) attached to the inner surface of the vibrating portion in this housing An ultrasonic transducer comprising
The ultrasonic transducer is inserted and assembled into the case having a shape (26) and a circular opening surface (22a) that can distinguish between the vertical direction and the left-right direction from the opening surface,
The internal space (13) of the housing has a shape that makes the directivity of the ultrasonic transducer different between the horizontal direction and the vertical direction,
The ultrasonic transducer according to claim 1, wherein identification means (17, 18) for identifying the horizontal direction and the vertical direction are formed on a side surface of the housing as an outer shape. The ultrasonic transducer according to claim 7, wherein the identification unit is a flat portion formed on a side surface of the housing. The ultrasonic transducer according to claim 8, wherein the flat portion is formed on both side surfaces of the housing. The ultrasonic transducer according to claim 9, wherein a vertical direction of a flat portion formed on both side surfaces of the housing exhibits directivity in the vertical direction.

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