JPH0537600Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention is an ultrasonic transformer that generates ultrasonic waves in response to electrical energization or generates electrical signals in response to sound waves. Regarding Yusa.

(Prior technology) An ultrasonic transducer in which a diaphragm is fixed to an electricity/vibration conversion element that converts voltage into mechanical displacement (change in shape or position) and pressure into an electrical value that can be converted into an electrical signal. is publicly known.

FIG. 6 shows an example of a conventional ultrasonic transducer. In this, the inner surface of the cup-shaped metal diaphragm 1 is deformed by the application of a voltage, and is a piezo element that generates a voltage by the application of pressure.
Vibration conversion element 2 connects one electrode of it to diaphragm 1
are bonded in contact with the One end of an electrical lead 3 is connected to the other electrode of the element 2, and the other end of the electrical lead 3 is connected to a terminal pin 4. One end of an electrical lead 5 is connected to the diaphragm 1, and the other end of the electrical lead 5 is connected to a terminal pin 6.

An O-ring 10 is fitted onto an insulating base 8 whose bottom surface is covered with a metal cap 7 and an O-ring-shaped elastic material 9 is bonded to the upper flange surface, and the opening edge of the diaphragm 1 is engaged with the opening. The diaphragm 1 is integrally fixed to the base 8 by caulking the edges into a ring shape 11.

The elastic material 9 and the O-ring 10 make the space between the diaphragm 1 and the base 8 watertight to prevent dirt and liquid (typically water) from entering, and do not hinder the vibration of the diaphragm 1.

When a voltage at an ultrasonic frequency is applied between the terminal pins 4-6, the element 2 expands and contracts in the radial direction at the frequency, thereby deforming the diaphragm 1 and generating ultrasonic waves outside the diaphragm 1.

An example of how this type of ultrasonic transducer is used is shown in FIG. 7a. This includes the presence or absence of obstacles at the rear of the vehicle, and if there are obstacles, the distance of the obstacles,
A vehicle is shown equipped with an ultrasonic transducer in the rear bumper of the vehicle to detect. In this example, one transducer emits ultrasonic waves, and one or more other transducers detect reflected ultrasonic waves. Another usage mode is to detect reflected waves using a transducer that emits ultrasonic waves.

A cross section of the ultrasonic sensor base 12 with the transducer mounted is shown in FIG. 7b. The transducer is further fixed to the base 12 via an elastic member 13 so that vibrations of the vehicle body do not affect the transducer.

(Problems to be Solved by the Invention) As shown in FIG. 6, the protruding length of the diaphragm 1 in the ultrasonic radiation direction is large, and the
Base 8 to support the elastic seal structure by 0
is thick, and the elastic material 13 is further inserted, so
Moreover, since the terminal pins extend in the ultrasonic emission direction (opposite direction), the thickness of the sensor base 12 that houses the transducer increases, and the bumper
The protrusion length is larger than BR. Therefore, the transducer is likely to malfunction due to objects hitting the base 12. In the embodiment shown in FIG. 7a, the base 12
By the time an object hits the vehicle, the transducer should detect it and stop the vehicle, but in many cases the object hits the vehicle while it is stopped. I also get nervous when washing my car. Not only that, but the entire diaphragm 1 must be floating above the base 8 and the base 12.
It is easy for mud and dirt to enter between the inner surface of the storage hole of the base 12 and the outer surface of the diaphragm 1.
function deteriorates. Or it becomes dysfunctional. It is difficult to remove mud and dirt, and object detection is likely to fail.

There is also a mode of use in which the transducer is housed inside the bumper BR so that the bumper BR does not hit an object. Its appearance is shown in FIG. 8a, and its cross section is shown in enlarged view in FIG. 8b. In this usage mode, the sensor base 14 is designed to use the bumper BR for its original purpose (excluding objects and preventing objects from colliding with the vehicle body) and to narrowly limit the direction of ultrasonic waves. is shaped like a horn, and the base is equipped with a transducer. In this case, mud or dirt gets inside the sensor base 14,
This removal is difficult and tends to result in object detection failure.

The primary purpose of the present invention is to provide an ultrasonic transducer with a small thickness in the ultrasonic transmission direction (ultrasonic arrival direction for reception only), and is suitable for use in places prone to dirt and dust, such as outside the car body. A second object is to provide an ultrasonic transducer that is easy to remove (clean).

[Structure of the idea]

(Means for Solving the Problems) In the present invention, the diaphragm has a vibration space surrounding part that protrudes into a cup shape and a flat plate part that is continuous with the vibration space surrounding part; Connect the conversion element; to the flat plate part of the diaphragm,
It has a lead through hole that penetrates in the thickness direction, and has electrical/
substantially closing the vibration space around the vibration conversion element;
A support substrate with low elasticity is bonded; an elastic member is bonded to the outer surface of the support substrate; an electrical lead, one end of which is connected to the electricity/vibration conversion element, passes through the electrical lead through hole and is supported along the support substrate. Pull out the outer surface of the board.

(Function) According to this, the flat plate portion of the diaphragm is integrally fixed with the support substrate, and the cup-shaped portion vibrates. The support substrate is a rigid body with respect to ultrasonic vibrations, and serves as an element for propagating ultrasonic vibrations to areas other than the diaphragm, thereby increasing the ultrasonic generation/reception efficiency. Compared to conventional materials, elastic material 9,
In the present invention, the combination of the O-ring 10 and the mounting elastic member 13 is only the above-mentioned elastic member, so the thickness in the ultrasonic emission/reception direction becomes extremely small, which not only makes installation easy, but also makes it easier to mount the diaphragm. Since there is a flat plate part continuous to the cup-shaped part, it is easy to remove mud and dirt.

In a preferred embodiment of the present invention, one electrode of the electric/vibration transducer element is connected to the ultrasonic transmitting circuit and/or receiving circuit by connecting the electric lead to the outside as described above, and the other electrode is connected to the ultrasonic transmitting circuit and/or receiving circuit. As before, it is brought into contact with a metal diaphragm. This electrode is normally connected to earth (common potential connection). Therefore,
Rivet holes are made in the flat plate portion of the diaphragm, and corresponding holes are also made in the support substrate, and the rivets are passed through these holes and the electrical connection tabs are applied to the outer surface of the support substrate and riveted. This electrical connection tab is connected to ground either directly or via an electrical lead. An elastic member is bonded to the outer surface of the support substrate, and electrical leads and electrical connection tabs along the outer surface of the support substrate are covered with the elastic member. In order to facilitate attachment to a required part of the transducer (for example, a bumper) and to increase attachment strength, a plate material such as an aluminum plate is bonded to the outer surface of the elastic member. In order to facilitate the installation work, a fixture is fixed to the plate material. The outer surfaces of the support substrate, the elastic member, and the plate on the electrical lead drawer side and the tab drawer side are coated with an elastic insulating material for electrical lead drawer seals and tab drawer seals.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Example) Fig. 1 shows the appearance of an embodiment of the present invention, and Fig.
The figure and Fig. 4 show its - line cross section and -
A line cross section is shown, and FIG. 3 shows the appearance of the components before assembly. The diaphragm 1 is a rectangular thin aluminum plate,
An asymmetrical frustum-shaped cup-shaped portion is formed by pressing to protrude from the flat plate portion. A disk-shaped piezo element 2, ie, an electric/vibration conversion element, is bonded to the inner surface of the most protruding part of this cup-shaped part, and an electrode on the surface thereof is in contact with the diaphragm 1. One end of an electrical lead 3 is connected to the other electrode.

There is a 90 degree fold 1 on the long side of the flat plate part of the diaphragm 1.
a, 1b are formed, and the surface of a steel plate 15, that is, a supporting substrate with low elasticity that acts as a rigid body and blocks vibrations of the diaphragm 1, is bonded to the flat plate part, and the folded part 1a is , iron plate 15 on 1b
The sides of the long sides are joined. This iron plate 15 closes the cup-shaped inner space of the diaphragm 1. This iron plate 15 has a lead extraction hole 22 that passes through it in the thickness direction, and the electrical lead 3 passes through this hole 22 and is pulled out along the iron plate 15 to its outer end (short side). There is.

In addition, holes are made in the flat plate part of the diaphragm 1 and the edge of the other short side of the iron plate 15, through which the rivets 16 are passed. A tab 17 is joined and fixed to the iron plate 15. Since the diaphragm 1 is a metal plate (aluminum thin plate) and is a conductor, and the rivet 16 and the iron plate 15 are also conductors, the tab 17 passes through the rivet 16 and the diaphragm 1, and also connects the iron plate 15 and the diaphragm. 1 and is electrically connected to one electrode of the piezo element 2.

On the back side of the iron plate 15 facing the piezo element 2, there is a foamed synthetic resin plate 18 made of a material with high elasticity, high vibration absorption effect (vibration from the transducer support part), and many air holes. It is joined.
A thin aluminum plate 19 is bonded to the resin plate 18 as the bottom plate of the transducer, and a permanent magnet plate (in this example, the short side one of them is N
and the other polarized to S) 20 are joined.

The outer surfaces of both short sides and the outer surfaces of both long sides of the diaphragm 1, the iron plate 15, the resin plate 18, the thin aluminum plate 19, and the permanent magnet plate 20 are made of flexible molded resin 21a for electrical terminal sealing. , 21b and 2
1c and 21d.

The assembly of this transducer (Figs. 1, 2, and 4) will be explained with reference to Fig. 3.
A steel plate 15 is joined to the diaphragm 1 to which the piezo element 2 is fixed. At this time, the electric lead 3 connected to the piezo element 2 is passed through the hole 22 of the iron plate 15 to integrate the diaphragm 1 and the iron plate 15, and then the rivet 16 is used to integrate the diaphragm 1 and the iron plate 15. A tab 17 is fixed to the back surface of the iron plate 15. Next, a resin plate 18 to which an aluminum plate 19 and a permanent magnet 20 have been bonded in advance is bonded to the back surface of the iron plate 15. Then, the side end surfaces of the short sides are covered with mold resins 21a and 21b.

The transducer described above has a bumper in which a resin body is bonded to the front side of an iron frame, and the transducer mounting hole EH (Fig. 2) is made in the resin body.
Insert into. This insertion joins the transducer's permanent magnet to the bumper's iron frame. Electrical leads (not shown) connected to tabs 17 and electrical leads 3 are routed to the back side of the bumper through holes through the iron frame. Even if mud or dirt gets into the mounting hole, it is easy to remove it because there is a space between the cup-shaped part and the mounting hole EH that corresponds to the flat plate part.

Note that the aluminum plate 19 is for reinforcing the back surface of the resin plate 18, and the permanent magnet 20 is for simple fixing, and depending on the application, both or one of them can be omitted. If you have these,
In addition, in any case where these are omitted, the resin plate 18 blocks vibrations from the transducer mounting side (for example, a bumper) to the transducer. Further, the vibration space communicates with the lead passage groove of the resin plate 18 through the lead passage hole 22, and the resin plate 18 absorbs the vibration pressure of the diaphragm 1, substantially preventing the propagation of ultrasonic vibration to the aluminum plate 19. Cut off. The cup-shaped portion of the diaphragm 1 vibrates, and the flat plate portion does not vibrate because it is joined to the iron plate 15. That is, the vibration of the diaphragm 1 is reflected by the iron plate 15 and is not propagated to the resin plate 18, so that the attenuation is small. This contributes to making the transducer thinner without deteriorating the electricity/vibration conversion efficiency of the diaphragm 1.

Further, as shown in FIG. 4, since the cup-shaped portion of the diaphragm 1 is vertically asymmetrical, the direction of the transmitted ultrasonic wave is directed from a line perpendicular to the tip surface of the diaphragm 1.
The direction out of the way, in this embodiment, is the upward direction. By making the shape of the cup-shaped portion asymmetrical in this way, the directivity direction of the ultrasonic waves can be set arbitrarily.

A specific example of the shape of the transducer of the present invention described above is as follows.

XW (long side length): 28mm YW (short side length): 25mm Thickness of diaphragm 1: 0.8mm Cup height PH: 2mm Element 2 mounting surface (most protruding surface): 12mm x 12mm Bottom of cup-shaped part: long side 22mm x short side 19mm UT: 5mm DT: 2mm (vertically asymmetrical, horizontally symmetrical) Iron plate 15 thickness: 1.6mm Resin plate 18 (urethane)
Thickness: 2mm Aluminum plate 19 thickness 0.8mm Permanent magnet plate 20 thickness: 2
mm Height from the bottom surface of the resin plate 18 to the top (sound wave transmitting end): 6.4 mm Height from the bottom (bottom surface of the permanent magnet plate 20) to the top (sound wave transmitting end): 9.2 mm In the above embodiment, the transformer The outer circumferential surface of the jacket is molded into a rectangular shape with seal resins 21a to 21d, but when the strength of the mold is further increased, it is necessary to
As shown in FIG.
b is buried between the lower surface of the diaphragm 1 and the upper surface of the permanent magnet 20, or a sealing resin 21b is buried between the lower surface of the diaphragm 1 and the upper surface of the permanent magnet 20, and the outer surfaces thereof are Cover.

[Effect of idea]

As described above, in the present invention, a supporting substrate with low elasticity is bonded to a vibrating member having a cup-shaped vibrating space surrounding portion and a continuous flat plate portion. It prevents the propagation of ultrasonic vibrations and has high ultrasonic generation/reception efficiency.

Furthermore, since the electrical leads penetrate the support substrate and are drawn out to the side along the plane of the substrate, the height in the ultrasonic emission direction is low, and even when the transducer is attached to an object, the electrical terminals can be placed outward from the side. Since it is extended, the mounting height in the ultrasonic emission direction becomes smaller. Therefore, in a usage mode in which the ultrasonic emission surface of the transducer is exposed to the outside air, there is a low possibility that objects will collide with the transducer, and the risk of damage to the transducer is correspondingly low. In addition, for example, when a transducer is installed inside the opening EH as shown in Figure 2, a flat plate is placed around the cup-shaped part, and a relatively wide space is created between the cup-shaped part and the opening EH. Therefore, even if mud or dirt enters the opening EH, it can be easily removed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the appearance of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is an exploded perspective view of the ultrasonic transducer shown in FIG. FIG. 4 is a sectional view taken along the - line in FIG. 1. FIGS. 5a, 5b and 5c are sectional views showing only the mold portions of other embodiments of the present invention. FIG. 6 is a vertical cross-sectional view of a conventional ultrasonic transducer, FIG. 7a is a perspective view of a vehicle equipped with this transducer, and FIG. 7b is a cross-sectional view of the sensor base 12 shown in FIG. 7a. It is a diagram. FIG. 8a is a perspective view showing another vehicle equipped with the ultrasonic transducer shown in FIG. 6, and FIG. 8b is a cross-sectional view of the center base 14 shown in FIG. 8a. 1... Vibration plate (vibration member), 2... Piezo element (electricity/vibration conversion element), 3, 5... Electric lead,
4, 6...terminal pin, 7...metal cap, 8...
... Base, 9 ... Elastic material, 10 ... O-ring, 11
...Caulking ring groove, 12, 14... Center base, BR... Bumper, 13... Elastic material, 15...
... Iron plate (support substrate with low elasticity), 16 ... Rivet, 17 ... Terminal tab, 18 ... Resin plate (elastic member), 19 ... Aluminum plate, 20 ... Permanent magnet, 2
1a, 21b...Mold resin, 22...Electric lead through hole.

Claims (1)

[Claims for Utility Model Registration] A vibrating member having a cup-shaped vibrating space surrounding part and a continuous flat plate part; An electric/vibration conversion element bonded to the inner surface of the vibrating space surrounding part; Penetrating in the thickness direction Has an electrical lead through hole,
a support substrate with low elasticity that is bonded to the flat plate portion of the vibration member and substantially closes the vibration space around the electricity/vibration conversion element; an elastic member bonded to the outer surface of the support substrate; connected to the electrode of the conversion element,
An ultrasonic transducer comprising: an electrical lead passing through the electrical lead through hole and extending along the support substrate and outwardly from the outer surface of the support substrate.