JP2000253495A - Dripproof type ultrasonic vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent dripproof ultrasonic vibrator which can change thickness of horizontal and vertical beams only by the ultrasonic vibrator. SOLUTION: In a dripproof ultrasonic vibrator which consists of a cylindrical case 1 one end of whose section is an open edge surface and the other of whose section is a closed edge surface, a piezoelectric element 2 stuck inside the closed edge surface of the cylindrical case 1, a sound absorbing material 3 arranged in a back side of the piezoelectric element 2, a lead line 4 connected to the piezoelectric element 2 and the cylindrical case 1, a shield line 6 for transmitting an input/output signal from a circuit side, a terminal substrate 5 for connecting the shield line 6 and the lead line 4, and a filling material 7 for filling the inside the cylindrical case 1, a projecting surface is formed by protruding one side as a whole of the closed edge surface of the cylindrical case 1 for one step and a thick part and a thin part are formed on a vibration surface of the cylindrical case 1.

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 for transmitting an ultrasonic signal and receiving 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, reflected by an obstacle such as an object to be detected, and the reflected wave is transmitted to an ultrasonic wave. Receive by the sensor, process the received signal,
It is configured to issue an alarm or the like. As shown in FIG. 7, the ultrasonic transducer transmitting the ultrasonic wave 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 side 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 cylindrical case 1, a shield line 6 for transmitting input / output signals from a circuit side (not shown), and a shield. Terminal board 5 for connecting wire 6 and lead wire 4 and cylindrical case 1
And a filler 7 that fills the inside. But,
In this ultrasonic vibrator, the vibration surface is circular, and the vibration surface thickness 1a of the case is uniform and constant.
The directivity becomes substantially uniform in all directions (horizontal direction and vertical direction) as 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, when the vehicle is mounted, a detection area in a lateral direction of the ultrasonic sensor is used to detect the presence of an obstacle. Although it is wide, in the vertical direction, a narrow detection area is required to remove the reflection of unnecessary objects on the road surface, and the beam direction differs in the horizontal direction (horizontal direction) and the vertical direction (vertical direction). Is required. Therefore, in the conventional ultrasonic vibrator, the horn 8 must be provided in front of the vibrator to control the ultrasonic beam. The horn needs a concave length from the surface as shown in FIG. 2, and the beam is controlled by the vertical diameter A, the horizontal diameter B, and the depth C of the opening.

[0004]

However, in the above-mentioned horn-type ultrasonic sensor, rainwater gets into the horn portion during traveling, and snow and dust easily accumulate, thereby causing an ultrasonic beam to be generated. The detection area may change due to the change. Alternatively, there is a problem in that an object that has entered the inside of the horn is detected, and even if an obstacle is not in the detection area, the horn is notified as if there is an obstacle. Also, since the horn is attached to the bumper or the like, a hole formed by attaching the horn is formed in the bumper.

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

[0006]

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

According to a second aspect of the present invention, the central portion of the surface of the vibrator is projected one step to form an oval convex surface.
A thick portion and a thin portion are formed on the vibration surface.

According to a third aspect of the present invention, the vibration surface is curved only in the axial direction corresponding to the horizontal direction of the vibration surface.

[0009] According to the contents of claim 4, claim 2)
Thus, the curved surface is formed only in the axial direction corresponding to the horizontal direction of the vibration surface.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a drip-proof ultrasonic transducer according to the present invention is shown in FIGS. 1 to 3, a second embodiment is shown in FIG. 4, and a third embodiment. 5 will be described in detail with reference to FIG. 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 vibrator according to the present invention.
FIG. 4 is a diagram illustrating a vibration mode of a vibration surface of a drip-proof ultrasonic vibrator. FIG. 3 is a diagram showing the directivity of the drip-proof ultrasonic transducer.

As shown in FIG. 1, the 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 2 bonded to the inner side of the closed end with an adhesive. A sound absorbing material 3 disposed on the back side of the piezoelectric element, a lead wire 5 from the piezoelectric element and the cylindrical case, a shield wire 6 for transmitting input / output signals from a circuit side (not shown), a shield wire 6 and a lead. It comprises a terminal board 5 for connecting the wires 4 and a filler 7 for filling the inside of the cylindrical case. The thickness of the closed end surface (hereinafter, referred to as a vibration surface) is set such that the center side vibration surface thickness a1 is thicker than the peripheral vibration surface thickness a2 only in the axial direction corresponding to the vertical direction of the vibrator, and Protrude shape.

Thus, 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 the figure, the vibrational shape in the axial direction corresponding to the vertical direction causes flexural vibration at the thick part a1 to which the piezoelectric element is attached, and the outside of the thick part is easily vibrated due to the thin part, so that Since the thin portion a2 bends so as to be attracted by the flexural vibration of the thick portion, the portion where the planar vibration is larger than in the horizontal direction vibrates.

As a result, the directivity in each direction (vertical direction and horizontal direction) on the vibrating surface of the vibrator is different between the vertical direction shown in FIG. 3B and the horizontal direction shown in FIG. 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.
By making the thickness of the vibrating surface in the axial direction, which corresponds to the vertical direction of the vibrator, thicker at the center and thinner at the periphery, the vibration of the vibrating surface in the axial direction is broadly vibrated.
Only the center part of the vibrating surface is made to protrude in an oval shape.

The basic configuration of the drip-proof ultrasonic vibrator of the present embodiment is very similar to that of the first embodiment. Detailed description is omitted.

Thus, as in the first embodiment, the vibration of the vibrating surface when the ultrasonic vibrator is driven is smaller in the vertical direction than in the horizontal direction of the vibrator. Can be caused to vibrate, and the vibration in the vertical direction as compared with the horizontal direction causes the plane vibration, so that the beam in the vertical direction can be 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 at one side.
A piezoelectric element 2 bonded to the inner side of the closed end face 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 input / output signals from the circuit side (not shown), the shield wire 6 and the lead wire 4 and a filler 7 for filling the inside of the cylindrical case.

The thickness of the vibrating surface is such that the central vibrating surface thickness a1 is larger than the peripheral vibrating surface thickness a2 only in the axial direction corresponding to the vertical direction of the vibrator, so that the vibrating surface protrudes toward the front surface side. The vibrator has an R-shaped curved surface on an axial vibration surface in the horizontal direction.

The basic configuration of the drip-proof ultrasonic vibrator of this embodiment is very similar to that of the first embodiment. Detailed description is omitted.

Accordingly, the vibration shape in the axial direction corresponding to the vertical direction can be changed to the thick portion a as in the first embodiment.
Since the thin portion a2 is bent so as to be pulled by the bending vibration of No. 1, the portion of the plane vibration vibrates to increase. On the other hand, the vibration shape in the axial direction corresponding to the horizontal direction has a spherical shape, so that the portion of the plane vibration is smaller than that in the case of the planar state. In addition, because of the spherical shape, a spherical wave is easily generated. This makes it possible to make the beam in the horizontal direction wider than in the above-described first embodiment, and it is possible to obtain different directivities in the vertical and horizontal beam thicknesses.

[Fourth Embodiment] As in the above-described third embodiment, when the vibrator is formed into a curved surface with an R only on the vibrating surface in the axial direction corresponding to the horizontal direction, the vibrator is in a planar state. Since the portion of the plane vibration is smaller and the spherical shape makes it easier to generate a spherical wave, the beam in the horizontal direction can be made thicker. Similar results can be obtained by projecting only the portion in an elliptical shape 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 vibrator of this embodiment is very similar to that of the first embodiment. Detailed description is omitted.

[0024]

As described above, according to the first and second aspects of the present invention, the vibration of the vibration surface of the ultrasonic vibrator is:
Vibration in the vertical direction can vibrate the entire vibrating surface compared to horizontal vibration of the vibrator, and vertical vibration will cause plane vibration compared to the horizontal direction. The vertical beam can be sharpened. This eliminates the need to control the ultrasonic beam with the horn as in the past, so that rainwater can enter the horn while driving, snow and dust collect, and the ultrasonic beam changes. If the detection area changes or the horn is detected inside the horn, it will no longer be notified that there is an obstacle even though the obstacle is not in the detection area. It has the effect of saying

In addition, when the horn type is mounted on a bumper or the like, a hole is formed.
Since the appearance is improved and the shape of the attaching portion of the piezoelectric element is flat as before, the effect of easily attaching the piezoelectric element to the cylindrical case can be maintained as before.

According to the third aspect of the present invention, in addition to the effects of the first and second aspects of the present invention, only the surface in the axial direction corresponding to the horizontal direction is curved, so that the The sound radiated to the radiator has an effect that a spherical wave is easily emitted and a wider beam can be radiated in the horizontal direction.

[Brief description of the 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.

FIG. 4 is a sectional view and a front view of a drip-proof ultrasonic vibrator according to a second embodiment of the present invention.

FIG. 5 is a sectional view and a front view of a drip-proof ultrasonic transducer according to a third embodiment of the present invention.

FIG. 6 is a sectional view and a front view of a drip-proof ultrasonic transducer according to a fourth embodiment of the present invention.

FIG. 7 is a cross-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]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic vibrator cylindrical case 2 Piezoelectric element 3 Sound absorbing material 4 Lead wire 5 Terminal board 6 Shield wire 7 Filler a1 Vibration surface thickness a2 Vibration surface thickness

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yusuke Hashimoto 1048, Kazuma Kadoma, Kadoma City, Osaka Pref. Terms (reference) 5D019 AA02 AA26 BB12 BB28 EE04 EE05 FF01 GG03 5J083 AA02 CA01 CA17 CA19 CA36 CB07 CB10

Claims (3)

[Claims] 1. A tubular case having a cross section having one open end and one closed end, a piezoelectric element bonded to the inside of the closed end 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 cylindrical case,
In a drip-proof ultrasonic vibrator made up of a shield wire for transmitting input / output signals from the circuit side, a terminal board for connecting the shield wire and the lead wire, and a filler for filling the inside of the cylindrical case, A drip-proof ultrasonic vibrator characterized in that a closed end surface of a cylindrical case is formed by projecting one step entirely in one direction to form a convex surface, and a thick portion and a thin portion are formed on a vibration surface of a cylindrical case. 2. The method according to claim 1, wherein a central portion of the surface of the cylindrical case is projected one step to form an elliptical convex surface, and a thick portion and a thin portion are formed on a vibration surface of the cylindrical case. Item 7. A drip-proof ultrasonic transducer according to Item 1. 3. The drip-proof ultrasonic vibrator according to claim 1, wherein only the axial direction corresponding to the horizontal direction of the vibration surface of the cylindrical case is formed as a curved surface.