RU2091974C1 - Method of excitation of longitudinal-and-torsional vibrations and device for its realization - Google Patents

Abstract

FIELD: vibration motors, microwelding sets, grinding acoustic devices, as well as various production process based on use of longitudinal-and-torsional vibrations. SUBSTANCE: the method consists in excitation in a waveguide of vibrations of various types, division of the front of vibrations excited in the waveguide into parts, direction of the latters at an angle to its surface on the path equal to Li.k - lambda i/4, where Li - path length of i-type vibrations, k-any integer, lambda i - wavelength of i-type vibrations, their direction is opposite on the same paths, strengthening and conversion of torsional vibrations in the waveguide to vibratory displacements. The vibration motor realizing the method uses a rotor and a concentrator of longitudinal-torsional vibrations, whose narrow part is made hollow and pressed to the rotor. A vibrator is attached to the end of the concentrator wider part. Lugs are made on the lateral surface of the concentrator wider part at an angle to it. The lug ends are stepped. The first steps are made on the lag lateral faces, their planes are perpendicular to the lug axis, the second steps are made on the lug upper and lower faces. The distance between the concentrator lateral surface and the first and second steps equals a quarter of the flexural and transverse wavelengths. The total length of the lugs equals a quarter of the wavelength of longitudinal vibrations. The lugs converge towards the concentrator. EFFECT: facilitated procedure. 4 cl, 5 dwg

Description

 The invention relates to mechanical engineering and can be used in the development of vibration motors, in micro-welding machines, grinding acoustic devices, as well as in various technological processes based on the use of longitudinal-torsional vibrations.

 Recently, there has been a growing need to develop new methods to implement high-intensity longitudinal-torsional vibrations in the designs of various devices and to achieve the required efficiency. This is especially true for microdevices (micromotors, microwelding devices, etc.), where due to the high requirements for weight and size characteristics, it is impossible to increase the intensity of longitudinal-torsional vibrations by increasing the mass of the converter or by increasing the supply voltage (restrictions apply, associated with the maximum allowable amplitudes of the oscillations of the transducers, due to the sufficiently low strength of the active material of the transducers).

A known method of producing ultrasonic longitudinal-torsional vibrations, including the excitation in the waveguide of ultrasonic vibrations of various types and their direction along the side surface of the waveguide at an angle to the generatrix [1]
The disadvantage of this method is the small amplitude of the longitudinal-torsional vibrations associated with the lack of amplification of these vibrations.

 A device is known that implements the indicated method, comprising a hollow radially polarized piezoceramic cylinder with several inclined electrode regions or several inclined slotted recesses, one end friction-jointed with a rotor, and the other end rigidly connected to the housing [1] Inclined electrode regions (slots) provide the occurrence and the orientation of the longitudinal torsional vibrations in the piezoceramic cylinder. The disadvantage of the vibration motor is the low rotor speed associated with the low amplitude of the longitudinal-torsional vibrations that enter the cylinder end, interacting with the rotor, without preliminary amplification.

A known method of producing ultrasonic longitudinal-torsional vibrations, including excitation of various types of vibrations in a waveguide, converting the direction of their propagation in a plane perpendicular to the waveguide, exciting radial and torsional vibrations, dividing the latter into parts, directing these parts at an acute angle to the propagation direction of these types of vibrations , excitation by radial and torsional vibrations of longitudinal vibrations, direction of the latter back to the waveguide, excitation by longitudinal vibrations of the vibrational displacement of torsional oscillations, amplification and introduction of the last waveguide gain obtained longitudinally torsional oscillation [2]
The disadvantages of the method are the relatively low amplitude of the longitudinal torsional vibrations and the efficiency of the method. This is due to the fact that only torsional vibrations are used to form torsional vibrations in a waveguide from the entire variety of excited types of vibrations. In addition, the multiple conversion of vibrations from one type to another (the conversion of vibrations excited in the waveguide into radial and torsional, and then the conversion of the latter into longitudinal vibrations and vice versa longitudinal vibrations into torsional vibrations) causes a significant loss of vibrational energy and thereby reduces the efficiency of the method generally.

 The specified method is implemented in a vibroengine [2] containing a hub and a rotor pressed to the end of its narrow part. The hub is made half-wave with a wide part whose length is equal to a quarter of the wavelength of torsional vibrations in the rod, and a narrow part made in the form of a hollow cylinder whose length is equal to a quarter of the wavelength of torsional vibrations in the rod. A wide part of the hub is connected to the flange, which is made in the form of a narrowed disk quarter-wave resonator of torsional vibrations. On the lateral surface of the flange around the circumference are inclined resonator rods, the length of which is equal to a quarter of the wavelength of longitudinal vibrations. Piezoelectric elements are drawn to the concentrator by means of a passive lining and bolted connection. When piezoelectric elements are excited from a source of high-frequency electrical vibrations, high-frequency mechanical vibrations arise in them, which, propagating in a concentrator, excite various types of vibrational displacements in it. Radial and torsional vibrations of the resonant flange excite longitudinal vibrations in inclined rods, which, interacting with the lateral surface of the disk at an acute angle, provide the appearance and orientation of torsional vibrations in the disk. The amplitude of torsional vibrations increases due to the difference in the cross-sectional areas of the wide and narrow parts of the concentrator. The energy of the longitudinal-torsional vibrations drives the rotor of the vibroengine.

 The disadvantages of the vibration motor are the relatively low rotor speed and efficiency, associated with a low concentration coefficient of torsional vibrations excited by longitudinal vibrations in the flange. This is because of the entire variety of vibrations excited in the concentrator, only longitudinal vibrations are used to create vibrational displacements of torsional vibrations in the flange. In addition, the multiple conversion of one type of oscillation to another causes a significant loss of vibrational energy and thereby reduces the efficiency of the device as a whole. In addition, radial vibrations will obviously be significantly weakened, since the geometric dimensions of the flange are resonant only with respect to torsional vibrations. Therefore, radial vibrations will not participate fully in the excitation of longitudinal vibrations in inclined rods.

 Closest to the proposed one is a method [3] comprising excitation of a front of oscillations of various types in a waveguide, dividing the front of oscillations into parts, directing the latter at an angle to its surface along paths equal to a quarter of the wavelengths of longitudinal and bending vibrations, isolating longitudinal and bending vibrations from all types of vibrations of the front parts, their direction back along the same path, amplification of longitudinal-torsional vibrations.

 The disadvantages of the method are the relatively low amplitude of the longitudinal torsional vibrations and the efficiency of the method. This is due to the fact that only longitudinal and bending vibrations are used in the formation of longitudinal-torsional vibrations in a waveguide from the entire variety of types of vibrations.

 In addition, the selected vibrations, before exposure to the waveguide, are not amplified, which does not allow to obtain a high amplitude of longitudinal-torsional vibrations.

 The specified method is implemented in a vibroengine [3] containing a longitudinal-torsional vibration concentrator in the form of a stepped cylinder with a wide and narrow hollow drive parts, a rotor pressed against the drive part of the concentrator, a vibration transducer pressed against the wide part of the concentrator by means of a passive plate and bolted connection. On the side surface of the wide part of the concentrator, tangentially fixed rod resonators are fixed to it, the ends of which are stepped, the cavity length being equal to a quarter of the wavelength of longitudinal vibrations, and the length of their wide part is a quarter of the wavelength of bending vibrations. The height of the wide and narrow parts of the concentrator is equal to a quarter of the wavelength of torsional vibrations.

 When connecting the piezoelectric elements of the vibration transducer to the source of high-frequency electrical vibrations (not shown in the drawings), ultrasonic mechanical vibrations arise in them. Propagating in the concentrator, these vibrations excite vibrational displacements of various types of vibrations, which excite longitudinal and bending vibrations in inclined rods, which, returning to the wide part of the concentrator, form torsional vibrations in the latter. Propagating in the concentrator, torsional vibrations are superimposed on the longitudinal ones and turn into longitudinal-torsional ones. Due to the difference in the cross-sectional areas of the wide and narrow steps of the concentrator, longitudinal-torsional vibrations are amplified. The energy of the longitudinal-torsional vibrations coming into the drive zone of a narrow stage drives the rotor.

 The disadvantages of the vibrator are relatively low speed and efficiency associated with a relatively low concentration coefficient of torsional vibrations excited in a wide part of the concentrator. This is because of the entire variety of vibrations excited in the concentrator, only longitudinal and bending are used to create vibrational displacements of torsional vibrations in the wide part of the concentrator.

 In addition, the distinguished types of vibrations involved in creating vibrational displacements of torsional vibrations are not further amplified before the lateral surface of a wide part of the concentrator is exposed.

 All this as a whole does not allow to achieve high speed and torque of the vibrator.

 The aim of the invention is to increase the amplitude of longitudinal torsional vibrations and to increase efficiency by increasing the concentration coefficient of vibrational displacements of torsional vibrations and reducing acoustic energy losses.

, где L_i длина пути i-го типа колебаний, k любое целое число, λ_i длина волны i-го типа колебаний, выделяют из указанных частей фронта остальные типы колебаний, распространяющихся в них, направляют обратно все типы колебаний по указанным выше путям, усиливают их и преобразуют в колебательные смещения крутильных колебаний в волноводе.This goal is achieved by the fact that in a method that includes excitation of a front of oscillations of various types in a waveguide, dividing the front of oscillation into parts, directing the latter at an angle to its surface along paths equal to quarter wavelengths of longitudinal and bending vibrations, isolating longitudinal and bending vibrations from all types of oscillations of the front parts, amplification of longitudinal-torsional vibrations, direct the indicated parts of the front along the paths

, where L _i is the path length of the ith oscillation type, k is any integer, λ _i is the wavelength of the ith oscillation type, the other types of vibrations propagating in them are extracted from the indicated parts of the front, and all types of vibrations are sent back along the paths indicated above, amplify them and transform them into vibrational displacements of torsional vibrations in the waveguide.

 The specified method is implemented in a vibroengine containing a rotor, a longitudinal-torsional vibration concentrator, the narrow part of which is hollow and pressed against the rotor, the wide part is connected to the vibration transducer at the end, the protrusions are fixed to the lateral surface of the wide part, the ends of which are made stepwise , the length of the protrusions is equal to a quarter of the wavelength of longitudinal vibrations, and the length of their wide part is equal to a quarter of the wavelength of bending vibrations, additionally, the ends of the protrusions have a third step, and The first steps are made on the lateral faces of the protrusions, and their planes are perpendicular to the axis of the protrusions, and the second steps on the upper and lower faces of the protrusions, while the planes of the second and third steps are perpendicular to the axis of the protrusions, and the distances from the side surface of the concentrator to the first, second and third steps are equal a quarter of the wavelengths, respectively, of bending, transverse and longitudinal vibrations.

 To create additional amplification of all types of vibrations, the protrusions are made tapering towards the concentrator.

, но затратит на это одно и то же время. Поэтому все типы колебаний вернутся к волноводу и воздействуют на него одновременно, в одной фазе и с одинаковой ориентацией направленности, что повысит коэффициент концентрации колебательных смещений крутильных колебаний, а следовательно, и амплитуду продольно-крутильных колебаний и эффективность способа. Усиление всех типов колебаний перед воздействием на волновод в свою очередь дополнительно повысит коэффициент концентрации колебательных смещений крутильных колебаний.A significant difference of the proposed method from the prototype is that torsional vibrations in the waveguide are excited by all types of vibrations, and not only longitudinal and bending, as in the prototype. Moreover, each type of oscillation, depending on the speed of propagation, will go its own way

, but it will take the same time. Therefore, all types of vibrations will return to the waveguide and act on it simultaneously, in the same phase and with the same orientation orientation, which will increase the concentration coefficient of vibrational displacements of torsional vibrations, and therefore the amplitude of longitudinal torsional vibrations and the efficiency of the method. The amplification of all types of vibrations before acting on the waveguide, in turn, will further increase the concentration coefficient of vibrational displacements of torsional vibrations.

 The difference between the claimed device and the prototype is that the ends of the protrusions have an additional third step, the first steps being made on the side faces of the protrusions, and their planes are perpendicular to the axis of the protrusions, the second steps on the upper and lower faces of the protrusions, while the planes of the second and third steps are perpendicular the axis of the protrusions, and the distances from the lateral surface of the concentrator to the first, second and third steps are equal to a quarter of the wavelengths, respectively, of bending transverse and longitudinal vibrations, while the protrusions made tapering towards the hub.

, что обеспечивает приход указанных типов колебаний к волноводу одновременно, в одной фазе и с одинаковой ориентацией направленности, а это в значительной мере обеспечивает усиление коэффициента концентрации крутильных колебаний. Изготовление выступов сужающимися к волноводу позволяет дополнительно усилить выделенные типы колебаний (продольные, поперечные и изгибные), что повышает эффективность их воздействия на поверхность концентратора и тем самым дополнительно повышает коэффициент концентрации крутильных колебаний.This embodiment of the protrusions makes them resonant with respect to the main vibrations propagating in them: longitudinal, transverse and torsional. In the protrusions, as in the "separator", there is a separation of the front parts into component types of vibrations (bending, longitudinal, transverse) and their direction back to the waveguide along the same paths

, which ensures the arrival of the indicated types of vibrations to the waveguide simultaneously, in the same phase and with the same directivity, and this largely ensures an increase in the concentration coefficient of torsional vibrations. The manufacture of protrusions tapering to the waveguide allows you to further strengthen the selected types of vibrations (longitudinal, transverse and bending), which increases the efficiency of their impact on the surface of the concentrator and thereby further increases the concentration coefficient of torsional vibrations.

 In FIG. 1 shows a vibroengine, section (section AA); figure 2 - step concentrator of the vibrator, top view; in Fig.3-5 inclined stepped protrusions indicating the direction of wave propagation and displacements of particles of various types of vibrations in them, and also plots of the corresponding vibrations propagating in these protrusions are shown.

в стержне. Высоты этих частей при необходимости могут изменяться в следующих пропорциях

где n 1, 3, 5. Торцы наклонных выступов 4 выполнены ступенчатыми. Причем первые ступени выполнены на боковых гранях выступа, а их плоскости перпендикулярны оси выступа, вторые ступени на верхних и нижних гранях выступа, а плоскости второй и третьей ступеней перпендикулярны оси выступа. При этом расстояния от боковой поверхности концентратора до первой, второй и третьей ступеней выступа равны соответственно

где λ_из, λ_n, λ_пр, длины волн соответственно изгибных, поперечных и продольных колебаний, К 1, 2, 3
Вибродвигатель работает следующим образом.The device contains (Fig. 1, 2) a longitudinal-torsional vibration concentrator with a wide part 1 and a narrow hollow drive part 2, a rotor 3 pressed against the drive part 2 of the concentrator, inclined, tapering towards the concentrator, protrusions 4 (bending, transverse resonators and longitudinal vibrations), performed on the lateral surface of the wide part 1 of the concentrator at an angle to it, the vibration transducer 5, for example, in the form of piezoelectric elements, a passive plate 6, which compresses the vibration transducer 5 to the end of the wide part 1 of the concentrator, for example, help of bolted connection 7. The vibrator motor concentrator is made half-wave. The height of its wide part 1 and narrow drive part 2, made in the form of a hollow cylinder, equal to a quarter of the wavelength of torsional vibrations

in the rod. The heights of these parts, if necessary, can be changed in the following proportions

where n 1, 3, 5. The ends of the inclined projections 4 are made stepwise. Moreover, the first steps are made on the side faces of the protrusion, and their planes are perpendicular to the axis of the protrusion, the second steps on the upper and lower faces of the protrusion, and the planes of the second and third steps are perpendicular to the axis of the protrusion. The distances from the lateral surface of the concentrator to the first, second, and third steps of the protrusion are equal, respectively

where λ _from , λ _n , λ _CR , the wavelengths of bending, transverse and longitudinal vibrations, respectively, K 1, 2, 3
The vibration motor operates as follows.

When the vibration transducer 5 is connected to a source of high-frequency oscillations (not shown in the drawings), high-frequency oscillations are excited in it, which, propagating in the concentrator, excite in the latter oscillatory displacements of various types of oscillations. The front of the wave of high-frequency oscillations in its path meets the inclined projections 4, which divide this front into symmetrical parts and transform the direction of propagation of these parts by 90 ^o . The indicated parts of the oscillation front during propagation along inclined protrusions, in turn, are divided into composite types of vibrations. In FIG. 3, 4, the principle of isolating bending, transverse, and longitudinal vibrations from the total mass is shown. The steps at the ends of the inclined protrusions are made in such a way that only one type of vibration is reflected from them, and the rest pass on without delay. In this case, the type of oscillations with the lowest wave propagation velocity is first distinguished, and then the others with the higher wave propagation velocity are successively.

где S₁ площадь сечения прохода между первыми ступенями,
S₂ площадь первых ступеней.Figure 3 shows the selection of bending vibrations, which in this case have the lowest wave propagation velocity. By the inclined protrusion from the concentrator, all types of vibrations begin to propagate almost simultaneously, then they are ahead of the longitudinal and transverse vibrations, which have a high propagation velocity. These types of vibrations will pass through the first stages without hindrance, since the directions of vibrational displacements of these types of oscillations do not coincide with the direction of the plane of these stages. For transverse and longitudinal vibrations, this will be an amplifying link in the form of a step concentrator (see the propagation diagrams of these oscillations in Fig. 4,5). The direction of displacement of the bending vibrations coincides with the direction of execution of the planes of the first steps. The first steps in this direction are made through. Bending vibrations due to the direction of their displacements cannot pass further, are reflected and come back (figure 3). Only part of the bending vibrations, which falls on a narrow passage between the first vertical steps, passes further. Then this part of the oscillations damps due to the mismatch of the geometric dimensions of the remaining part of the inclined protrusions with the resonance conditions for this type of oscillation. Therefore, we do not consider this part and attribute it to inevitable losses. The percentage of losses can be expressed by the ratio:

where S ₁ the cross-sectional area of the passage between the first steps,
S _{2 the} area of the first steps.

 At the second through steps of the inclined concentrators, the longitudinal vibrations will pass with the next gain. For longitudinal vibrations, this can be considered as the second stage of a step concentrator (Fig. 5).

 For vibrational displacements of transverse vibrations, the direction of the indicated planes of the through steps will coincide. Therefore, transverse vibrations, as in the previous case, will be reflected. Only a part of the oscillations that fit into the width of the narrow passage between the steps will pass. Losses from this part of the vibrations are calculated in the same way as for bending vibrations.

, то изгибные, поперечные и продольные колебания достигнут каждые своих ступеней одновременно и одновременно отразятся. В результате они достигнут боковой поверхности концентратора также одновременно и воздействуют на нее в одной фазе и с одинаковой ориентацией направленности. Так как выступы 4 (фиг. 2) направлены под углом к боковой поверхности широкой части 1 концентратора, то указанные выше колебания будут формировать в данной широкой части 1 концентратора колебательные смещения крутильных колебаний.The longitudinal vibrations, having reached the third stage, will be reflected completely without loss and, like bending and transverse vibrations, will return back to the concentrator. Since the distances to the first, second and third steps are equal, respectively

, then bending, transverse and longitudinal vibrations will reach each of their steps simultaneously and simultaneously reflected. As a result, they reach the lateral surface of the concentrator also simultaneously and act on it in one phase and with the same orientation. Since the protrusions 4 (Fig. 2) are directed at an angle to the side surface of the wide part 1 of the concentrator, the above vibrations will form vibrational displacements of torsional vibrations in this wide part 1 of the concentrator.

 Since bending, transverse and longitudinal vibrations act on a wide part 1 of the concentrator simultaneously, in the same phase and with the same orientation, their action will cause a significant increase in the concentration coefficient of vibrational displacements of torsional vibrations. The implementation of inclined rod resonators tapering towards the wide part 1 of the concentrator causes an additional increase in the concentration coefficient of vibrational displacements of torsional vibrations and their amplitude and increases the efficiency of the device as a whole. High-amplitude torsional vibrations interact with longitudinal vibrations. The longitudinal-torsional vibrations propagate in the wide part 1 of the concentrator, and then pass into the narrow drive part 2 of the concentrator, further enhancing the amplitude due to the difference in the cross-sectional areas of wide 1 and narrow 2 parts of the concentrator. The energy of the longitudinal-torsional vibrations coming into the drive zone of the narrow part 2 of the hub drives the rotor 3.

 The layout of the vibration motor that implements the inventive method has the following characteristics: maximum diameter D 38 mm, length 25 mm; power consumption 10-12 W, speed 10-12 thousand rpm, moment M = 10-50 g • cm. (depends on the clamping force of the drive part of the hub to the rotor), the operating frequency f = 98 kHz, weight ≈ 30 G.

Claims (4)

1. A method of obtaining longitudinal-torsional vibrations, including the excitation of a front of oscillations of various types in a waveguide, dividing the front of oscillations into parts, the direction of the latter at an angle to its surface, amplification of longitudinal-torsional vibrations, characterized in that all types of vibrations are distinguished from these parts propagating in them by directing the indicated parts of the front along the paths

where l _i the path length of the i-th type of oscillation;
K any integer;
λ _i - wavelength of the i-th type of oscillations,
direct the selected types of vibrations back along the paths indicated above and convert them into vibrational displacements of torsional vibrations in the waveguide.  2. The method according to claim 1, characterized in that it further amplifies all types of vibrations isolated from the front parts before converting them into vibrational displacements of torsional vibrations in the waveguide.  3. A vibroengine containing a rotor, a hub of longitudinal-torsional vibrations, the narrow part of which is hollow and pressed against the rotor, the wide part is connected to the vibration transducer at the end, on the side surface of the wide part, there are oblique to it, fixed protrusions, the ends of which are made stepwise, at this length of the protrusions is equal to a quarter of the wavelength of longitudinal vibrations, and their length to the first step is equal to a quarter of the wavelength of bending vibrations, characterized in that the ends of the protrusions have an additional stage, made on erhnih and lower faces of the projections at a distance equal to a quarter of the wavelength of transverse oscillations from the side surface of the concentrator, the first step is formed on the side faces of the projections.  4. The vibration motor according to claim 3, characterized in that the protrusions are made tapering towards the hub.

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