JP3367446B2 - Drip-proof ultrasonic transducer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic transducer of an ultrasonic sensor that transmits an ultrasonic signal and receives a reflected wave from an obstacle to detect the presence of the obstacle.

[0002]

2. Description of the Related Art As a conventional ultrasonic sensor for detecting an obstacle, an ultrasonic pulse is transmitted from the ultrasonic sensor into the air and reflected by an obstacle such as an object to be detected. Received by the sensor, processing the received signal,
It is configured to issue an alarm or the like. As shown in FIG. 7, an ultrasonic transducer emitting the ultrasonic waves has a cylindrical case 1 having a cross-section open at one end and a closed end on one side, and a piezoelectric element 2 bonded to the inner surface of the closed end with an adhesive. A sound absorbing material 3 arranged on the back side of the piezoelectric element 2, a lead wire 4 from the piezoelectric element 2 and the tubular case 1, a shield wire 6 for transmitting an input / output signal from the circuit side (not shown), and a shield Terminal board 5 for connecting wire 6 and lead wire 4, and cylindrical case 1
And a filling material 7 for filling the inside of the. But,
In this ultrasonic vibrator, the vibration surface is circular, and the thickness 1a of the vibration surface of the case is uniform and constant.
The directivity is substantially uniform in all directions (horizontal and vertical directions) when viewed from the ultrasonic transducer.

However, in an ultrasonic sensor for detecting an obstacle for a vehicle, the sensor is mounted on a bumper or the like of the vehicle. Therefore, the lateral detection area of the ultrasonic sensor at the time of mounting the vehicle is for detecting the presence of an obstacle. Although it is wide, it is necessary to have a narrow detection area in the vertical direction to remove the reflection of unnecessary objects on the road surface, and the beam thickness is different in the horizontal direction (horizontal direction) and the vertical direction (vertical direction). Sex is needed. Therefore, in the conventional ultrasonic transducer, it is necessary to have the horn 8 in front of the transducer to control the beam of the ultrasonic waves. As shown in FIG. 2, the horn needs to have a recessed length from the surface, and the beam is controlled by the longitudinal diameter A, the lateral diameter B, and the depth C of the opening.

[0004]

However, in the horn type ultrasonic sensor described above, rainwater easily enters the horn portion during traveling, snow and dust are likely to accumulate, and the ultrasonic beam is thereby generated. It may change and the detection area may change. Alternatively, there is a problem that the object that has entered the horn is detected and the alarm is issued as if there is an obstacle even though the obstacle is not in the detection area. In addition, since it is attached to a bumper or the like, a hole for attaching the horn is formed in the bumper, which causes a problem that the appearance is not good.

The present invention has been made in view of this point, and an object of the present invention is not beam control by a horn of an ultrasonic sensor, but the thickness of vertical and horizontal beams only by an ultrasonic transducer. It is an object of the present invention to provide an excellent drip-proof ultrasonic vibrator capable of changing the temperature.

[0006]

According to the first aspect of the present invention, a convex surface is formed by projecting one whole surface of the vibrator in one direction, and a thick portion and a thin portion are formed on the vibrating surface. It is characterized by.

According to the second aspect of the invention, the central portion of the surface of the vibrator is made to protrude by one step to form an elliptical convex surface,
It is characterized in that a thick portion and a thin portion are formed on the vibrating surface.

[0008] In the context of claim 3, also claim 1
2 ) is characterized in that the curved surface is formed only in the axial direction corresponding to the horizontal direction of the vibrating surface.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a drip-proof ultrasonic transducer according to the present invention is shown in FIG. 1 to FIG. 3, a second embodiment is shown in FIG. 4 and a third embodiment. 5, and the fourth embodiment will be described in detail with reference to FIG.

[First Embodiment] FIG. 1 is a sectional view and a front view of a drip-proof ultrasonic transducer according to the present invention, and FIG. 2 shows vibration of a vibration surface of the drip-proof ultrasonic transducer. It is a figure which shows a mode. FIG. 3 is a diagram showing the directivity of the drip-proof ultrasonic transducer.

As shown in FIG. 1, a drip-proof ultrasonic transducer has a cylindrical case 1 having a cross-section open at one end and a closed end on one side, and a piezoelectric element 2 bonded to the inner surface of the closed end with an adhesive. , The sound absorbing material 3 arranged on the back side of the piezoelectric element, the lead wire 5 from the piezoelectric element and the cylindrical case, the shield wire 6 for transmitting an input / output signal from the circuit side (not shown), the shield wire 6 and the lead It is composed of a terminal board 5 for connecting the wires 4 and a filling material 7 for filling the inside of the cylindrical case. The thickness of the closed end surface (hereinafter, referred to as a vibrating surface) is set so that the central vibrating surface thickness a1 is thicker than the peripheral vibrating surface thickness a2 only in the axial direction which is the vertical direction of the vibrator, and Make it stick out.

As a result, the vibration mode of the vibrating surface of the vibrator has a simple flexural vibration shape in the axial direction corresponding to the horizontal direction of the vibrator, as shown in FIG.
As shown in Fig. 5, the axial vibration shape corresponding to the vertical direction causes flexural vibration in the thick portion a1 to which the piezoelectric element is attached, and the thin portion on the outside of the thick portion easily vibrates. Since the thin portion a2 is bent so as to be attracted by the flexural vibration of the thick portion, the plane vibration portion vibrates so as to be larger than in the horizontal direction.

As a result, the directivity in each direction (vertical direction and horizontal direction) on the vibrating surface of the vibrator is the vertical direction shown in FIG. 3 (b) and the horizontal direction shown in FIG. 3 (a). It is possible to obtain directivity with different vertical and horizontal beam thicknesses with a half-value angle ratio of about 1: 2.

[Second Embodiment] As shown in FIG. 4, by virtue of making the axial vibrating surface, which is the vertical direction of the vibrator, thick in the central portion and thin in the peripheral portion, In order to make the vibration of the vibrating surface in the axial direction widely and planarly vibrate, only the central portion of the vibrating surface is formed in an elliptical shape.

The basic structure of the drip-proof ultrasonic transducer of this embodiment is very similar to that of the first embodiment, and the same parts are designated by the same reference numerals and the details thereof will be given. Description is omitted.

As a result, similarly to the above-described first embodiment, the vibration of the vibrating surface when the ultrasonic vibrator is driven is such that the vibration in the vertical direction is larger than that in the horizontal direction of the vibrator. It is possible to vibrate, and the vibration in the vertical direction makes a plane vibration in comparison with the horizontal direction, so that the beam in the vertical direction can be made sharper than in the horizontal direction.

[Third Embodiment] A drip-proof ultrasonic vibrator has a cylindrical case 1 having a cross-section open at one end and a closed end on one side, and a piezoelectric element bonded to the inner surface of the closed end with an adhesive. 2, the sound absorbing material 3 arranged on the back side of the piezoelectric element, the lead wire 5 from the piezoelectric element and the tubular case, and the shield wire 6 for transmitting input / output signals from the circuit side (not shown).
A terminal board 8 for connecting the shield wire 6 and the lead wire 4, and a filler 7 for filling the inside of the cylindrical case.
It consists of

The thickness of the vibrating surface is such that only in the axial direction which is the vertical direction of the vibrator, the vibrating surface thickness a1 on the central side is made thicker than the vibrating surface thickness a2 on the periphery so as to project to the front surface side. Then, a curved surface with an R is formed on an axial vibrating surface corresponding to the horizontal direction of the vibrator.

The basic structure of the drip-proof ultrasonic transducer of the present embodiment is very similar to that of the first embodiment, and the same parts are designated by the same reference numerals and the details thereof will be given. Description is omitted.

As a result, the vibrating shape in the axial direction, which corresponds to the vertical direction, is the same as in the first embodiment described above, ie, the thick portion a.
Since the thin portion a2 bends so as to be attracted by the flexural vibration of No. 1, the planar vibration portion vibrates to become large. On the other hand, since the vibration shape in the axial direction corresponding to the horizontal direction is spherical, the plane vibration portion becomes smaller than that in the case of the plane state. Further, because of the spherical shape, spherical waves are also likely to occur. As a result, the horizontal beam can be made thicker than in the above-described first embodiment, and directivity with different vertical and horizontal beam thicknesses can be obtained.

[Fourth Embodiment] As in the above-described third embodiment, in the case of a planar state, the curved surface with R is formed only on the axial vibration surface that is in the horizontal direction of the vibrator. Compared with, the plane vibration part is smaller, and because the spherical shape makes it easier to generate spherical waves, it is possible to thicken the horizontal beam, so that the center of the vibration surface as shown in FIG. The same result can be obtained by projecting only the part in the shape of an ellipse and forming the curved surface only in the axial direction corresponding to the horizontal direction of the surface.

The basic structure of the drip-proof ultrasonic transducer of the present embodiment is very similar to that of the first embodiment, and the same parts are designated by the same reference numerals and their details will be described. Description is omitted.

[0023]

As described above, according to the first and second aspects of the invention, the vibration of the vibrating surface of the ultrasonic transducer is
Vertical vibration can vibrate the entire vibrating surface as compared to horizontal vibration, and vertical vibration causes planar vibration compared to horizontal vibration. It is possible to sharpen the beam in the vertical direction. This eliminates the need to control the ultrasonic beam with a horn as in the past, and rainwater may enter the horn while driving, snow or dust may accumulate, and the ultrasonic beam may change. , If the detection area changes or something inside the horn is detected, it will not be reported that there is an obstacle even if there is no obstacle in the detection area. Has the effect of saying.

Also, when the horn type had a hole when it was mounted on a bumper or the like, since the hole was also removed,
Since the appearance is improved and the shape of the attachment portion of the piezoelectric element is flat as in the past, the ease of attaching the piezoelectric element to the cylindrical case has an effect that the conventional workability can be maintained.

According to the third aspect of the present invention, in addition to the effects of the first and second aspects of the present invention, by further forming only the axial surface, which is the horizontal direction, into a curved surface, the horizontal direction of the ultrasonic transducer is increased. The sound radiated to becomes easier to emit a spherical wave, and a thicker beam can be emitted in the horizontal direction.

[Brief description of drawings]

FIG. 1 is a sectional view and a front view of a drip-proof ultrasonic vibrator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a vibration mode of a vibration surface of the drip-proof ultrasonic vibrator.

FIG. 3 is a diagram showing the directivity of the drip-proof ultrasonic transducer.

4A and 4B are a sectional view and a front view of a drip-proof ultrasonic transducer according to a second embodiment of the invention.

5A and 5B are a sectional view and a front view of a drip-proof ultrasonic transducer according to a third embodiment of the invention.

6A and 6B are a cross-sectional view and a front view of a drip-proof ultrasonic transducer according to a fourth embodiment of the invention.

FIG. 7 is a sectional view and a front view of a conventional ultrasonic transducer.

FIG. 8 is a diagram showing a horn shape of a conventional ultrasonic sensor.

[Explanation of symbols] 1 Ultrasonic transducer cylindrical case 2 Piezoelectric element 3 sound absorbing material 4 lead wire 5 terminal board 6 shielded wire 7 Filling material a1 Vibration surface thickness a2 Vibration surface thickness

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Naoya Higashi 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) Bibliography Sho 58-166599 (JP, U) (58) Fields investigated Int.Cl. ⁷ , DB name) H04R 17/00 330 G01S 7/521 H04R 1/32 330

Claims (3)

(57) [Claims] 1. A cylindrical case having an open end surface at one end and a closed end surface at the other end, a piezoelectric element bonded to the inside of the closed end surface of the cylindrical case, and a sound absorbing material disposed on the back side of the piezoelectric element. And a lead wire connected to the piezoelectric element and the tubular case,
A drip-proof ultrasonic transducer comprising a shielded wire for transmitting an input / output signal from the circuit side, a terminal board for connecting the shielded wire and a lead wire, and a filling material filling the inside of the cylindrical case. A drip-proof ultrasonic transducer, characterized in that a convex surface is formed by projecting one whole direction in one direction of a closed end surface of a cylindrical case, and a thick portion and a thin portion are formed on a vibrating surface of a cylindrical case. 2. The cross section has an open end surface at one end and a closed end surface at the other end.
And the inside of the closed end surface of the tubular case.
Piezoelectric element and sound absorbing material arranged on the back side of the piezoelectric element
And a lead wire connected to the piezoelectric element and the tubular case,
A shield wire that transmits input / output signals from the circuit side, and a seal
Terminal board for connecting lead wires and lead wires, and cylindrical
Drip-proof ultrasonic waves consisting of a filler that fills the inside of the case
In the vibrator, a drip-proof type characterized in that the central part of the surface of the cylindrical case is made to protrude one step to form an elliptical convex surface, and a thick part and a thin part are formed on the vibrating surface of the cylindrical case. Ultrasonic transducer. 3. The drip-proof ultrasonic transducer according to claim 1, wherein a curved surface is formed only in the axial direction corresponding to the horizontal direction of the vibration surface of the cylindrical case.