The invention relates to ultrasound technique, namely to the structures of ultrasonic oscillatory systems, and can be used in the development of ultrasonic medical equipment. The technical result of the invention is to increase the amplitude of oscillations, improving the reliability of work, reduction overall dimensions and masses. The ultrasonic oscillatory system is made in the form of a span of rotation and is formed by sequentially located two metal lining, reflective and concentrating, and two piezoelectric elements located between overlays, acoustically connected with each other with a tight element. Piezoelements are made by disc, reflective pad consists of sequentially arranged threaded stops with a central hole and disk lining. The concentrating pad contains three sections: the first - cylindrical with the flange, the second - exponential and third - output cylindrical with a threaded deaf hole for fastening the waveguide tool, and the steering element is made in the form of a glass with internal thread and two holes: round in the center of the bottom and rectangular On the side surface of the glass. The first cylindrical portion of the concentrating lining is made of a threaded to the flange, a precipitant nut is additionally placed on this site. 2 il.

Drawings to the Patent of the Russian Federation 2465071

The invention relates to the field of ultrasonic technology and serves to obtain and transmit mechanical oscillations of dialing, sound or supersonic frequency and can be used in any technological processes that are used using ultrasound.

Ultrasonic oscillatory systems (piezoceramic converters) of Langezhen type are known [E.Kikuchi. Ultrasonic converters. M.: Mir Publishing House, 1972, p.472; FRG Patent No. 2711306 MKI B06V 3/00]. This type of converters is a mosaic scored from slices of quartz-cut and concluded between two metal plates. Disadvantages of piezoceramic converters this type Are: non-technological design, complexity of assembly and low power.

Ultrasonic oscillatory systems (emitters) of the type "Sandwich" [S.S. Volkov, B.Y. Chernomak are also known. Welding plastics ultrasound. M.: Chemistry, 1986, p.126; Novikov A.A., Negro D.A., Schuster Ya.B. On the issue of determining the effort of the screed of piezoceramic converters of a longitudinal type. Materials of the III of the International Scientific and Technological Congress "Military Technology, Armament and Double Application Technologies". - Omsk. - 2005. - Part 1. - p.177-178; Certificate of utility model RU No. 18655. Ultrasonic ceramic emitter. / Novikov A.A., Schuster Ya.B., Negro D.A. Publ. Bi No. 19, 2001], one of which is chosen as a prototype [RU 2141386 "Ultrasonic oscillatory system" Barsukov R.V. et al.] as the closest in technical essence to the proposed. It is an oscillatory system in the form of a rotation body formed by sequentially located and acoutyly connected with two metal lining and two piezoelectric elements located between the lining, and the forming of the rotation of the oscillating system is made in the form of a continuous bold curve, and the body of rotation consists of three sections : The first cylindrical, second plot with an exponential or smooth radius change in the diameter of the section, and the third - cylindrical, and the annular piezoelectric elements are located between the exponential and first cylindrical portion, which are connected by a tight element (for example, a bolt or stud).

Emitters like "sandwich" are free from the lack of emitters of the Langevin type described above. They are easy to manufacture and assembly, however, with small diameters of the used piezoocolets, the diameter of the inner hole in the piezocoltz becomes the value limiting the energy parameters of the oscillating system, since on the one hand reduces the active surface of the piezoelectric unit, and on the other - it leads to the need for such a decrease in the diameter of the brassing stud or bolt in which the strength characteristics of the console element do not provide reliable operation of the oscillatory system as a whole.

The technical result of the invention is to increase the amplitude of oscillations while improving the reliability of work and a significant decrease in the overall dimensions and mass of the ultrasonic oscillatory system.

The technical result is achieved in the fact that in a known device, which represents an ultrasonic oscillatory system in the form of a body of rotation, formed by the sequentially located two metal lining, reflecting and concentrating, and two piezoelectric elements located between overlays, acoutyly interconnected by the consistent element according to the claimed invention. , Piezoelements are made by disc, reflective pad consists of a sequentially arranged threaded stop with a central hole and a disk lining, the concentrating pad contains three sections: the first - cylindrical with the flange, the second - exponential and third - output cylindrical with a threaded deaf hole for fastening the waveguide-tool, A tie element is made in the form of a glass with internal thread and two holes: round in the center of the bottom and rectangular on the side surface of the glass, and the first cylindrical section of the concentrating lining And a threaded to the flange is made and a cape nut is additionally placed on this site.

The assembly drawing of the proposed device is shown in Fig. 1 and contains the following elements: a concentrating overlay 1, inserted into the round hole of the glass 2 so that its position is fixed with the flange of the lining; Piezoelements 3 with contact petals 4, protruding through a rectangular glass of 5 cup 2, fixed in a glass 2 using a disk cover 6 and fluoroplastic tape in the form of a cut ring 7 and threaded stop 8. The cape 9 is located on a cylindrical flange segment of the concentrating overlay 1.

The proposed device works as follows.

When the high-frequency voltage is applied to the conclusions of contact petals 4, protruding through a rectangular opening 5 of the side surface of a glass 2, piezoceramic discs 3 carry out the transformation of the electrical signal into an acoustic signal.

When working as an acoustic oscillatory system [Novikov A.A., Schuster Ya.B., blacks yes. Features of the design of the ultrasonic piezoceramic converter with half-wave length. Omsky scientific Bulletin. - 2009. Ser.: Instruments, machinery and technology. - № 3 (83). - C.194-198.], The distribution of the amplitudes of longitudinal acoustic oscillations by the length of this acoustic system will look, as shown in Fig.2. At the same time, the "zero" fluctuations will be on the region of the cylindrical flange portion of the concentrating lining 1, so the location on this section of the precipitated nut 9 will allow it to be used for the rigid fastening of the entire oscillatory system in the emitter housing with a minimum of fastening elements on the characteristics of the speaker system. On the other hand, the use of glass 2 as a consuming element, translates the structure of an ultrasonic acoustic system from a system with an internal screed (the most widespread currently both in our country and abroad), in the design of systems with an external screed. This, firstly, it provides the possibility of using as a piezoactive elements not the ring, and the discs that with the same diameters of the speaker system makes it possible to increase the output acoustic power, which is the more significant than the smaller the diameter of the piezoelectric elements, and secondly, eliminates the problem ensuring the necessary strength and reliability of the internal consignment element.

The rectangular opening 5 on the side surface of the glass 2 is used to output the contact petals 4 through it, and the hole in the threaded stop 7 provides not only the possibility of screaking piezo no, but the possibility of some correction of the frequency characteristics of the oscillating system.

Thus, the proposed ultrasonic acoustic system allows:

Obtain effective small-sized ultrasound emitters when using piezoelements (disks) of small diameters;

Achieve the minimum effect of the elements of fastening the acoustic system in the housing of the ultrasound emitter;

Increase the amplitude of the system oscillations while improving the reliability of work with a significant decrease in overall dimensions and mass, which is extremely necessary for modern ultrasound medical equipment.

CLAIM

The ultrasonic oscillatory system in the form of the body of rotation formed by sequentially located two metal linings reflecting and concentrating, and two piezoelectric elements located between the lining, acoustically associated with each other, characterized in that the piezoelectric elements are made by disk, reflective pad consists of sequentially arranged threaded Stop with a central hole and disk lining, the concentrating pad contains three sections: the first - cylindrical with the flange, the second - exponential and third - output cylindrical with a threaded deaf hole for fastening the waveguide tool, and the steering element is made in the form of a glass with internal thread and two Holes: Round in the center of the bottom and rectangular on the side surface of the glass, and the first cylindrical section of the concentrating lining is made of a threaded to the flange and a precipitated nut is additionally placed on this site.

To generate ultrasound, special emitters of the magnetostrictive type are used. The main parameters of the devices include resistance and conductivity. Also taken into account the permissible value of the frequency. By design, the device may differ. It should also be noted that the models are actively used in echo sounds. To understand the emitters, it is important to consider their scheme.

Device scheme

Standard magnetostrictive ultrasound emitter consists of a stand and set of terminals. Directly magnet is supplied to the condenser. At the top of the device there is a winding. At the base of emitters, a clamping ring is often installed. Magnet fits only neodymium type. In the upper part of the models is the rod. For its fixing, a ring is applied.

Ring modification

Ring devices operate when conducting 4 MK. Many models are manufactured with short stands. It should also be noted that there are modifications on field capacitors. To collect the magnetostrictive emitter with their own hands, a solenoid winding is applied. In this case, the terminals are important to establish low threshold voltage. Ferrite neck is more expedient to select a small diameter. The clamping ring is raised last.

Device with Yar.

Make a magnetostrictive emitter with your own hands is quite simple. First of all, the rack under the rod is harvested. Next, it is important to cut a stand. To do this, you can use a metal disk. Specialists suggest that the stand in diameter should be no more than 3.5 cm. Terminals for the device are selected on 20 V. In the top of the model, the ring is fixed. If necessary, you can wind the isolent. The resistance indicator in the emitters of this type is located in the area of \u200b\u200b30 ohms. They work at the conductivity of at least 5 MK. Winding B. this case No need.

Double winding model

Double winding devices are made of different diameters. The conductivity of the models is at 4 MK. Most devices have high wave resistance. To make a magnetostrictive emitter with your own hands, only the steel stand is used. Insulator in this case will not need. Ferrite rod is allowed to install on lining. Experts recommend in advance to harvest the sealing ring. It should also be noted that the field-type capacitor will be required to assemble the emitter. The inlet resistance at the model should be no more than 20 ohms. Winding are installed next to the rod.

Reflector emitters

Emitters of this type are highlighted by high conductivity. Models work at a voltage of 35 V. Many devices are equipped with field capacitors. Make a magnetostrictive emitter with your own hands is pretty problematic. First of all, it is necessary to choose a small diameter rod. At the same time, the terminals are harvested with conductivity from 4 MK.

Wave resistance in the device should be from 45 ohms. The plate is installed on the stand. The winding in this case should not come into contact with the terminals. At the bottom of the device is obliged to be a round stand. An ordinary tape is often used to fix the ring. The capacitor is attacked above the manganite. It should also be noted that rings are sometimes used with overlays.

Devices for echolotov

For echolotov, the magnetostrictive emitter is often used. How to cook the model with your own hands? Homemade modifications are made with conductivity from 5 MK. They are on average equal to 55 ohms. To make a powerful ultrasonic rod applied to 1.5 cm. The solenoid winding is screwed down with a small step.

Specialists suggest that the racks for the emitters are more expedient to pick up stainless steel. At the same time, the terminals are applied with low conductivity. Capacitors are suitable for different types. Emitters are at 14 W. Rubber rings are used to fix the rod. The base of the device is winding the tape. It is also worth noting that the magnet should be installed last.

Modifications for fishing companies

Devices for fishing devices are collected only with wired capacitors. To begin with, install the rack. It is more expedient to use rings with a diameter of 4.5 cm. The solenoid winding is obliged to fit tightly to the rod. Quite often, capacitors are soldered at the base of emitters. Some modifications are made on two terminals. Ferrite necklace is obliged to be fixed on the insulator. To strengthen the ring, the tape is used.

Low wave resistance models

Low devices wave resistance Work at a voltage of 12 V. Many models have two capacitors. To assemble a device that generates ultrasound, with your own hands, you will need a rod by 10 cm. In this case, the radiator capacitors are installed by the wired type. The winding is winding at the last turn. It should also be noted that the terminal will need for assembly. In some cases, field condensers are used for 4 MK. The frequency parameter will be quite high. Magnet is expedient to be installed above the terminal.

High Wave Resistance Devices

High resistance ultrasound emitters are well suited for short wave receivers. You can collect your own device only on the basis of transitional capacitors. At the same time, the terminals are brewing high conductivity. Quite often, the magnet is installed on the rack.

The stand for the emitter is applied by a low height. It should also be noted that one straighten is used to build the device. For the insulation of its base, the usual tape is suitable. In the rather part of the emitter, there is a ring.

Rod devices

The stem-type scheme includes a winding conductor. Capacitors are allowed to apply different capacity. At the same time, they may differ in conductivity. If we consider simple modelThe stand is harvested round a round form, and the terminals are installed at 10 V. The solenoid winding is screwed at the last turn. It should also be noted that the magnet is selected neodymium type.

Directly the rod applies to 2.2 cm. Terminals can be installed on the lining. It is also necessary to mention that there are modifications by 12 V. If we consider devices with high-capacity field capacitors, then the minimum diameter of the rod is allowed 2.5 cm. In this case, the winding should coolant to isolation. In the upper part of the emitter, a protective ring is installed. Stands are allowed to do without a lining.

Models with single-pass capacitors

The emitters of this type provide conductivity at the level of 5 MK. At the same time, the wave resistance indicator of them at a maximum of up to 45 ohms. In order to independently make the emitter, a small stand is harvested. At the top of the stand is obliged to be a rubber pad. It should also be noted that the magnet is harvested with a neodymium type.

Experts advise him to establish it. Terminals for the device are selected by 20 W. The capacitor is directly installed above the lining. The rod is used in a diameter of 3.3 cm. At the bottom of the winding must be ring. If we consider models into two capacitor, the rod is allowed to be used with a diameter of 3.5 cm. The winding should coolant to the very base of the emitter. At the bottom of the drainage of the tape is glued. Magnet is installed in the middle of the rack. Terminals should be located on the parties.

The property of ultrasonic waves is reflected from the obstacle and return back in the form of echo is used to determine the distance to hard-to-reach objects.

Known at the beginning of the twentieth century, mechanical sources of ultrasound waves - totamons and oscillating steel rods, possessed high power, but were not able to send them a narrow directional beam, like a light beam. The ultrasound emitted by them was divided into different directions. Because of this, it was impossible to determine the direction in which the object was studied.

But the release of French scientist Paul Lanzhen found. In 1916, during the First World War, he was looking for a way of detecting submarines using ultrasound. And as a source of ultrasonic waves, he used a piezoelectric phenomenon, which before that did not find applications.

Opening of piezoelectricity

Click on the picture

Piezoelectric effect was opened in 1880 by French scientists Pierre and Curie field During the study of the properties of crystals. Squeezing the quartz crystal on both sides, they found the appearance of electrical charges on the edges perpendicular to the direction of compression. The charges on one face were positive, and on the other - negative. They observed the same picture with the stretching of crystals. On that face where, when compressed, positive charges appeared, with tension there were negative, and vice versa.

Pierre Curie

It turned out that besides quartz, the crystals of the tourmaline, segained salts, lithium sulfate, and other crystals, which have no center of symmetry have such properties. This phenomenon was called piezoelectricity, From the Greek word "Piezo" - i dut, and crystals with such properties - piezoelectrics.

With further research, the Curie brothers found that there is and reverse piezoelectric effect. If you create electric charges Different polarity on the edges of the crystal, then it will be squealing or stretching.

This discovery and used in its studies Paul Lanzhen.

Piezoelectric emitter Langevena

Paul Lanzhen

If a quartz plate is mechanically exposed, it is electrified. And vice versa, if you change the electrical field with a certain frequency in which it is, it will start fluctuate with the same frequency.

And what will happen if to charge the crystal to use electricity from the high frequency alternating current source? Having done such an experience, Lanzhen was convinced that the crystal oscillation frequency is the same as the frequency of voltage change. If it is below 20,000 Hz, the crystal becomes a sound source, and if higher, it will emit ultrasonic waves.

But the power of ultrasound emitted by one plate of the crystal is very small. Therefore, from quartz records, the scientist created a mosaic layer and placed it between two steel linings, which performed the functions of the electrodes. To increase the amplitude of oscillations, the phenomenon of resonance was used. If the frequency of the alternating voltage supplied to the piezocrystal coincided with its own frequency, then the amplitude of its oscillations increased dramatically.

This design was called "Lanzhen Sandwich". And she was very successful. The radiation power was large enough, and the beam of the waves was narrowly directed.

Later as a piezoelectric element instead of quartz plates began to use ceramics from barium titanate, the piezoelectric effect of which is many times higher than that of quartz.

Piezoelectric record can be a sound receiver. If a sound wave He will meet her on his way, the record will start fluctuate with the frequency of sound source. Electrical charges will appear at its faces. The energy of sound oscillations is converted into the energy of electrical oscillations, which are captured by the receiver.

It can be said that ultrasound transducers were born in water. In 1826, the radiance and assault on the Lake Geneva was measured for the first time the speed of propagation of sound in water with the help of a church bell. Even before this experiment, Leonardo da Vinci noted that the water spends the sound well. However, it is possible to be quite definitely considered that the experiment 1826 is the first time of use for radiation of sound in the water of the resonant device. In the future, underwater bells excited by electromagnetic or pneumatic hammers were used to measure the depths of the acoustic method and for other navigation purposes. By its form, the underwater signal bell was distinguished from church. The edge was made very thick, to improve the resonant properties of the bell when working in water, the acoustic impedance of which is more than 3000 times the acoustic air impedance. As hydrophones, coal microphone capsules enclosed in the metal case were used. To obtain increased acoustic power for some time, water sirens were used, the movable part of which was rotated in a water tank attached to the inner surface of the ship housing. But in 1907, a Fesanten generator appeared (Fig. 2.1), which was applied to underwater alarm.

Fig. one.

The generator was created on the basis of an induction (asynchronous) engine using an electrodynamic effect. The vibrations of the thick metal diaphragm were excited by a thick copper tube of a certain length, which could move freely in the axial direction in a strong constant radial magnetic field. The primary winding at which the alternating current was sweeping, was wound on the core located inside in such a way that the copper tube was the only short-circuited twice of the secondary winding. Induced by copper tube Secondary current, interacting with a constant field, created a variable mechanical force. The mechanical system of the generator was very massive to overcome the large acoustic impedance of the medium. The alternating current was supplied from the high-frequency generator, and the frequency was chosen equal to the resonant frequency of the diaphragm in contact with water, since the efficiency of the electroacoustic transformation during excitation outside the mechanical resonance drops noticeably. Fessenden generators with resonant frequencies 540, 1050 and 3000 Hz were produced by industry and for quite a long time were used in practice for underwater alarm and measuring the depths acoustic method. Up to those remote times, ultrasound waves were not used at all.

Fig. 2.

But with intelligent dimensions of the emitter, the sound of audible frequencies applies to the water in the water. In addition, audible sound can be very annoying passengers and a ship's command. With these points of view, as well as taking into account certain military applications, it became clear to the need to use ultrasound waves. In 1920, a suitable ultrasonic emitter appeared, designed for signaling from submarines and called Langevin emitter (Fig. 2.2).

This emitter is a mosaic scored from chocks of quartz x cut and concluded between two thick metal plates. If an alternating voltage is applied to the plates, a piezoelectric forcing force occurs in quartz crystals, and together with rigidly connected plates begin to fluctuate as a single mechanical system. The frequency of the excitation electrical voltage is selected equal to the frequency of the main longitudinal mode of fluctuations of this three-layer structure. The surface of the metal plate, addressed to water, performs piston oscillations, and the direction of the emitter turns out to be sufficient at the diameter of the plate of about 30-40 cm. The opposite surface of another plate is usually in contact with air, so that it does not give acoustic radiation.

In 1933, magnetostrictive vibrators made of thin sheets of metal were invented. The oscillating core of such a vibrator is made in the form of a set of hundreds of glued thin plates settled from sheet nickel. Electrical windings are placed in windows provided when stamping. Magnetostriction force generating force is created alternating currentwhose frequency is usually selected equal to the frequency of the mechanical core resonance. The thickness of the individual plate is selected in accordance with the operating frequency, taking into account the magnetic permeability and the electrical resistance of the material so that the losses on the vortex currents do not exceed a certain value, since they are the main factor determining the electro-acoustic efficiency of the transducer. Magnetostriction converters of this type could be improved by developing new alloys with a large and large magnetostriction effect and, consequently, the possibility of transforming greater power. In contrast to this lanching emitters, the source of the excitation force of which depends on the nature of the quartz crystals, have less perfection opportunities. Their acoustic power was limited to the voltage of the breakdown of the crystal. In addition, durable and uniform bowls of mosaic from crystals to a large surface of a metal plate, susceptible to strong variable stressesrelated to technical difficulties. On the contrary, in magnetostriction vibrators, gluable surfaces are exactly parallel to the direction of oscillations, and since it is about variable mechanical stresses, there is no need to take precautions to ensure gluing strength. These advantages of magnetostriction vibrators contributed to the rapid displacement of lanes converters. Further studies were conducted by various alloys, and in 1942 an aluminum alloy with iron called alferom was obtained, the use of which reduced the cost of magnetostriction converters. Vibrators from this alloy quickly found wide use not only in ultrasound echo sounds, but also in fishing different types. Soon, however, a large piezoelectric effect was discovered in an artificial ferroelectric, called the ceramics of the titanate barium, and the development of technological methods made products from ceramics sufficiently mechanically durable for use in ultrasonic oscillations. This happened over time since 1947 to 1950. The generating force occurs in such material when exposed to an alternating electric field, as in the quartz crystal, but in this case there is still a constant electrical polarization - an electrical displacement. The coefficient of electromechanical communication for the ceramics of the Barium titanate is significantly higher than for quartz, and due to this they again remembered the emitter of Langeve. In connection with the development of durable artificial resins, such as Aralitis, ultrasound transducers like Langevin with ceramic plates from Barium titanate instead of quartz mosaic again entered the practice. The high coefficient of the electromechanical connection of the material and small dielectric losses in it have hoped to hope that the use of such converters will help increase the overall efficiency of various ultrasound installations.

Fig. 3.

Despite the fact that the difficulties mentioned above, inherent assembly techniques, were not overcome for the Barium titanate converter, it found a fairly wide practical application in various low-powerful ultrasonic equipment, in particular in compact fishing techniques, where he made a serious competitor of magnetostriction converters from an alfer or nickel.

During the time from 1954 to 1957, new useful magnetostriction materials were obtained - ferrites; As a result of the industrial development of their technology, the mechanical strength of ferrites was achieved sufficient to radiate high-power ultrasound. Due to the fact that ferrites have a very high electrical resistance, the losses for vortex currents are not felt for them in any monolithic volume of the material, and the vibrator can be made immediately in the final form of ferrite powder by pressing and subsequent firing. The electro-acoustic coefficient of the efficiency of ferrites is obviously higher than the efficiency of metal magnetostriction vibrators scored from thin plates, and usually exceeds the latter by about 3 times, reaching 80-90%. The characteristic advantages of the magnetostrictive converter compared to piezoelectric are inherent in any ferrite converter. Therefore, in many areas of industrial use, ultrasound is currently used primarily converters.