JP3632393B2 - Ultrasonic transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic transducer.
[0002]
[Prior art]
FIG. 3 shows a side sectional view of a conventional ultrasonic transducer. A conventional ultrasonic transducer includes a protective net 1, a storage case 2, a cylindrical case 3, a support base 4, a piezoelectric element 5, a diaphragm 6, a resonator 7 having a cone shape, a lead. A line 8 and an external terminal 9 are included.
[0003]
The storage case 2 has a cylindrical shape and has a circular opening 10 at the center of the top.
[0004]
The protective net 1 is a circular dust-proof net formed of a thin non-woven fabric or the like that does not allow dust to pass through but passes through the ultrasonic wave almost without being attenuated. The opening 10 of the storage case 2 is blocked.
[0005]
The cylindrical case 3 has a cylindrical shape with a diameter that can be accommodated in the cylindrical portion of the storage case 2, and the height is processed slightly shorter than the storage case 2.
[0006]
The support base 4 has a columnar shape, and has a hook-shaped portion 4a on the entire outer periphery of the bottom surface. The outer diameter of the bowl-shaped portion 4 a has such a diameter that it just fits within the cylindrical shape of the storage case 2. Further, the central cylindrical portion 4 b of the support base 4 has a diameter that can be fitted into the cylindrical case 3. The support base 4 is fixed by caulking the bottom surface base end of the storage case 2 after the hook-like portion 4 a of the support base 4 is brought into contact with the bottom base end of the cylindrical case 3.
[0007]
The piezoelectric element 5 is an element that generates vibration in response to application of a voltage, and is mounted and fixed on the central cylindrical portion 4 b of the support 4.
[0008]
The diaphragm 6 is a metal disk and is bonded and fixed to the upper surface of the piezoelectric element 5. The resonator 7 has a cone shape, and the top of the resonator 7 is bonded and fixed to the approximate center of the diaphragm 6. The diaphragm 6 and the resonator 7 are desirably bonded with an elastic adhesive, and a rubber adhesive or the like is used.
[0009]
The lead wire 8 connected to the piezoelectric element 5 is connected to an external terminal 9 that is inserted into and fixed to the support base 4.
[0010]
In this ultrasonic transducer, by inputting a burst signal as shown in FIG. 4A from the lead wire 8 to the piezoelectric element 5, the piezoelectric element 5 is driven to vibrate the diaphragm 6 and the resonator 7. Generate ultrasound.
[0011]
In the ultrasonic transducer having this configuration, when a burst signal as shown in FIG. 4A is input from the external terminal 9 of the ultrasonic transducer for Ta time and an ultrasonic wave is generated, the ultrasonic transducer shown in FIG. Thus, even when the Ta time elapses, the vibration of the ultrasonic vibrator is generated while being attenuated as reverberation vibration. (In FIG. 4B, it takes Tb time to attenuate to the threshold value Vth or less.)
As shown in FIG. 5, when the distance between the ultrasonic transducer and the obstacle is L meters and the sound velocity is c meters per second, the emitted ultrasonic wave is reflected by the obstacle and the reflected wave returns after 2 L / c seconds. It will be. At this time, the shorter the distance between the ultrasonic transducer and the obstacle, the closer the reflected wave from the obstacle and the above-mentioned reverberation vibration will be in time, and in some cases, the reflection is reflected in the reverberation signal. Waves may hide. For this reason, the conventional ultrasonic transducer has a problem that the obstacle cannot be detected if the distance between the obstacle and the ultrasonic transducer becomes too short.
[0012]
In order to solve this problem, as shown in FIGS. 6A and 6B, a flexible film 11 made of a rubber film, a synthetic resin film, or the like is formed on a part or all of the inner wall of the resonator 7. Processing such as sticking is performed. Thereby, the reverberation vibration can be quickly attenuated by the bending of the flexible film 11.
[0013]
[Problems to be solved by the invention]
However, in the ultrasonic vibrator having the above-described configuration, vibration during driving of the ultrasonic vibrator propagates to the protective net 1 via the support base 4, the cylindrical case 3, and the storage case 2. Since the storage case or the like vibrates, the attenuation of the reverberation vibration becomes unstable due to the influence of vibrations other than the piezoelectric element 5, the diaphragm 6 and the resonator 7. As a result, as shown in FIG. 4C, the reverberation signal generation time Tb is extended, and the reverberation signal is mistakenly recognized as a reflected wave from an obstacle, or a reflected wave from an obstacle at a short distance cannot be recognized. Has the problem.
[0014]
The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to suppress reverberation vibration generated in a protective net, a storage case, and the like due to ultrasonic wave transmission driving, and stably approach it. An object of the present invention is to provide an ultrasonic transducer capable of recognizing a reflected wave from an obstacle at a distance.
[0015]
[Means for Solving the Problems]
According to the first aspect of the present invention, a resonator, a diaphragm to which the resonator is fixed, a piezoelectric element to which the diaphragm is fixed, a support base for fixing the piezoelectric element, and a support base are fixed to the support base. An ultrasonic vibrator having a cylindrical case for positioning the support base in a fitting direction, and a cylindrical storage case for storing the cylindrical case and the piezoelectric element, the support base, and the like. Thus, the cylindrical case and the support base are fixed via a buffer material that reduces propagation of vibration.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of an ultrasonic transducer according to the present invention will be described in detail based on FIG. 1 and a second embodiment will be described in detail based on FIG.
[0018]
[First Embodiment]
FIG. 1 is a side sectional view of an ultrasonic transducer according to the present invention.
[0019]
The ultrasonic vibrator includes a protective net 1, a storage case 2, a cylindrical case 3, a support base 4, a piezoelectric element 5, a disc-shaped diaphragm 6, and a resonator 7 having a cone shape. And a lead wire 8, an external terminal 9, and a buffer material 12. In FIG. 1, the same parts as those of the ultrasonic transducer shown in FIG. 3 described in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
The support base 4 has a bowl-shaped portion 4a on the entire outer periphery of the bottom surface. And the convex protrusion 4c is formed in the perimeter or a part of the upper surface tip of the bowl-shaped part 4a. After the convex protrusions 4 c of the support base 4 are brought into contact with the bottom base end of the cylindrical case 3, the bottom base end of the storage case 2 is caulked so that the bottom base end of the storage case 2 and the cylindrical case 3 The convex protrusion 4c is clamped between the bottom end of the storage case 2 and the storage case 2 and the support base 4 are fixed.
[0020]
At that time, the protective net 1 is pressed against the top bottom surface of the storage case 2 by the top surface base end of the cylindrical case 3, and as a result, the top bottom surface of the storage case 2 and the top base end of the cylindrical case 3. It will be pinched between them.
[0021]
The side surface in the vicinity of the bottom surface of the support base 4 and the flanged portion 4a and the cylindrical case 3 are fixed via a cushioning material 12 such as a felt material formed of rubber, sponge, or fiber. Thus, the vibration that has been propagated to the cylindrical case 3 from the side surface near the bottom surface of the support base 4 and the hook-shaped portion 4 a conventionally propagates to the cylindrical case 3 through the cushioning material 12.
[0022]
In this ultrasonic transducer, by inputting a burst signal as shown in FIG. 4A from the lead wire 8 to the piezoelectric element 5, the piezoelectric element 5 is driven to vibrate the diaphragm 6 and the resonator 7. Generate ultrasound.
[0023]
At this time, the vibration of the piezoelectric element 5, the vibration plate 6 and the resonator 7 propagates to the support 4, but the shock absorbing material 12 absorbs the vibration, so that the vibration to the cylindrical case 3 and the storage case 2 is reduced. Propagation is suppressed. Accordingly, it is possible to prevent the protection net 1 and the storage case 2 from vibrating due to the vibration of the piezoelectric element 5, the diaphragm 6 and the resonator 7, and the protection net 1 and the storage case 2 vibrate. Therefore, it is possible to reduce the occurrence of unnecessary reverberation vibration.
[0024]
Moreover, if the storage case 2 is crimped and the support base 4 is directly fixed as in the present embodiment, the storage case 2 and the support base 4 can be securely fixed.
[0025]
[Second Embodiment]
FIG. 2 is a side sectional view of the ultrasonic transducer according to the present invention.
[0026]
The ultrasonic vibrator includes a protective net 1, a storage case 2, a support 4, a piezoelectric element 5, a disk-shaped diaphragm 6, a cone-shaped resonator 7, a lead wire 8, And an external terminal 9.
[0027]
The ultrasonic transducer according to the second embodiment is different from that of the first embodiment described above in the following configuration.
[0028]
The storage case 2 has a cylindrical cylindrical shape, has a circular opening 10 at the center of the top, and has a net mounting convex part 2a on the entire circumference or a part of the inner wall of the cylinder near the top. ing. In addition, a positioning convex portion 2 b for positioning the support base 4 in the fitting direction is provided on the entire circumference or a part of the inner wall of the cylinder in the vicinity of the bottom base end of the storage case 2.
[0029]
The protective net 1 is fixed by being sandwiched between the top of the storage case 2 and the net mounting convex part 2a.
[0030]
The support base 4 has a cylindrical shape, and a cushioning material 12 is attached to the outer periphery of the bottom surface over the entire circumference. The portion of the support base 4 to which the cushioning material 12 is attached is provided with a cushioning material mounting convex portion 4d. As a result, the bonding area between the support base 4 and the cushioning material 12 can be increased, and when an external force in the vertical direction is applied between the support base 4 and the cushioning material 12, the cushioning material mounting convex portion 4d is formed. It acts as a stopper and prevents the cushioning material 12 from being easily detached from the support base 4.
[0031]
The support base 4 is fixed by caulking the bottom end of the storage case 2 after bringing the cushioning material 12 attached to the support base 4 into contact with the positioning projection 2b. As a result, all vibrations that have been propagated to the cylindrical case 3 from the side surface near the bottom surface of the support base 4 and the flange-shaped portion 4 a in the past are mediated by the cushioning material 12.
[0032]
In this ultrasonic transducer, by inputting a burst signal as shown in FIG. 4A from the lead wire 8 to the piezoelectric element 5, the piezoelectric element 5 is driven to vibrate the diaphragm 6 and the resonator 7. Generate ultrasound.
[0033]
At this time, the vibration of the piezoelectric element 5, the diaphragm 6 and the resonator 7 propagates to the support 4. However, since the buffer material 12 absorbs the vibration, the cylindrical case 3 and the storage case 2 are absorbed by the buffer material 12. Propagation of vibration to is suppressed. Accordingly, it is possible to prevent the protection net 1 and the storage case 2 from vibrating due to the vibration of the piezoelectric element 5, the diaphragm 6 and the resonator 7, and the protection net 1 and the storage case 2 vibrate. Therefore, it is possible to reduce the occurrence of unnecessary reverberation vibration.
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention , the piezoelectric element is driven by inputting a burst signal to the external terminal of the ultrasonic transducer, and thereby the diaphragm and the resonator are vibrated, thereby super In the ultrasonic transducer that generates sound waves, the shock absorber can prevent the vibration generated when the ultrasonic waves are generated from propagating to the protective net or storage case via the support base. It is possible to reduce the reverberation vibration generated by the net for the use of the product, the storage case, etc., and there is an effect that it is possible to provide an ultrasonic transducer that can stably recognize the reflected wave from an obstacle at a short distance. .
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view of an ultrasonic transducer according to an embodiment of the present invention.
FIG. 2 is a side sectional view of an ultrasonic transducer according to another embodiment of the present invention.
FIG. 3 is a side sectional view of a conventional ultrasonic transducer.
FIG. 4 is a timing chart showing a relationship between a burst signal input to the ultrasonic transducer and an ultrasonic wave output from the ultrasonic transducer, and (a) shows a waveform of the burst signal input to the ultrasonic transducer. FIGS. 4B and 4C are waveform diagrams of ultrasonic waves generated by inputting a burst signal.
FIG. 5 is a schematic diagram showing the positional relationship between an ultrasonic transducer and an obstacle.
6A and 6B are diagrams illustrating a conventional ultrasonic transducer, in which FIG. 6A is a side cross-sectional view, and FIG. 6B is an enlarged perspective view of a diaphragm and a resonator.
[Explanation of symbols]
2 Storage case 3 Cylindrical case 4 Support base 5 Piezoelectric element 6 Diaphragm 7 Resonator 12 Buffer material

Claims (1)

A resonator, a diaphragm to which the resonator is fixed, a piezoelectric element to which the diaphragm is fixed, a support base for fixing the piezoelectric element, and a support base fixed to the support base in a direction in which the support base is fitted In an ultrasonic vibrator having a cylindrical case for positioning, and a cylindrical storage case for storing the cylindrical case and the piezoelectric element, the support base, etc., propagation of vibration is reduced in the storage case. An ultrasonic vibrator characterized in that the cylindrical case and the support base are fixed via a buffer material.

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