RU2728886C1 - Method for correction of dynamic state of working member of process vibration machine with vibration exciter on elastic support and device for implementation thereof - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to the field of machine building. Dynamic condition of process machine is corrected. Vibrations of working element are excited. Oscillations are measured, the ratio of oscillation amplitudes is adjusted in different points of the working element and influence of force actions on extreme points of the working element by means of movement of the adjustable vibration exciter along the surface of the vibration process machine. Device comprises working element resting on support elastic elements. Vibration exciter is made with possibility to move along working tool surface in longitudinal direction and rests on pneumo-cylinder with adjustable stiffness. Dynamic state sensors are located at the edges of the working member.

EFFECT: achieving dynamic state of the vibration process machine by changing the position of the vibration exciter.

2 cl, 3 dwg, 1 tbl

Description

The invention relates to the field of vibration technology and can be used in the modernization of vibration technological machines.

Vibrating machines in the form of technological stands are widely used in various industries. The dynamics of machines of this kind are distinguished by a variety of operating states, the form of interaction of external elements and increased loads.

The vibration background that accompanies the operation of vibration stands needs to be assessed and adjusted to the levels and forms of exposure, which is determined by the requirements for ensuring the quality of manufactured products, rationing of vibration effects for service personnel and dynamic loads on production facilities.

Many issues of ensuring the dynamic states of vibration technological machines are considered in special literature [1-3]. The peculiarity of the operation of vibration stands, as well as other machines operating under conditions of intense dynamic loading, is the need for a sufficiently detailed attention to the tasks of assessing, monitoring and changing dynamic states required by technological regulations.

Known design and technical solutions that provide the possibility of appropriate settings for the distributions of the amplitudes of oscillations of points of the working body along its length, the formation of certain structure and parameters of vibration fields.

In the course of the patent search, a number of analogous inventions were identified.

Known invention [Matseevich B. V., Mikhailov V. D., Savchenko V. P., Feofanov V. M., Yanbulatov R. I., Golikov N. A. "Vibrating machine for pre-sowing seed treatment", patent No. 2130417, IPC B65G 27/00, B65G 27/18, priority 20.05.1999], which is a quasi-shock vibration frame containing a base, a receiving frame mounted on elastic suspensions of the base, and a vibration exciter receiving frame. An elastic beam is introduced into the device, fixed with one end to the base parallel to elastic suspensions. The free end of the elastic beam is connected to at least two links rigid in tension and unstable in compression, directed to one of the sides of the oscillatory movement of the receiving frame. The free end of one of the links is fixed to the frame, and the other to the base. The technical effect is to increase the efficiency of technological equipment.

The disadvantages of this invention are the lack of means for moving the vibration exciter and the lack of devices for regulating the dynamic state of the vibration machine.

Known device for damping vibrations [Eliseev S. V., Ermoshenko Y. V., Moskovskikh A.O., Bolshakov RS "Device for damping vibrations", patent No. 2498126 C2, IPC F16F 7/112, F16F 15 / 027 priority 11/10/2013], containing elastic elements and a system of dynamic vibration damping in the form of an elastically attached mass. The object of protection contains an adjustable system of dynamic vibration damping. The dynamic damping system contains a pneumatic cylinder with a valve, a compressor with a pipeline and a control system with sensors. The air spring is secured to a base plate that moves in a dovetail joint with a self-braking screw device. The sensors are installed at the protected object and on the dynamic vibration damper and transmit information about the state of the protected object and the dynamic damper to the information processing unit for making a decision on turning on the compressor and the screw device. Achieved dynamic damping of vibrations in two coordinates.

The considered invention has a number of disadvantages, which include the lack of functions in the control system to obtain a mode of a single relationship between the coordinates of motion.

Known invention [Serga G. V., Reznichenko S. M. "Vibrating machine for pre-sowing seed treatment", patent No. 2585476, IPC А01С 1/00, priority 12/30/2014], containing a grinding drum, the inner surface of which is covered with a layer of rubber, with an unloading window, a working body, a dosing hopper, an unloading chute, installed resiliently on the base. The grinding drum is made of conical, multi-thread, screw and is assembled from guiding elements made of three or more twisted along a helical line in the longitudinal direction relative to the longitudinal axis and curved along a helical line in the transverse direction on a mandrel in the form of a paraboloid of rotation of strips made with side edges of a convex curvilinear shape, with gaps and described by curves of various orders and degrees of curvature. At the same time, along the entire length inside the grinding drum, overlaps are formed in the form of helical blades, and along the entire length of the grinding drum, a conical spring with a flat section of turns and a device for changing the pitch of the turns by stretching or compressing the spring is mounted. The simplified design of the device allows expanding its technological capabilities.

The disadvantages of this technical solution include the lack of automatic control of the dynamic state.

The prototype is the device [V.I. Antipov, R.I. Antipova, A.V. Koshelev, N.N. Dentsov. "Vibration conveying machine", patent No. 2532235, IPC В06В 1/00 priority 10.07.2012], which includes a working body connected by an elastic connection to the reactive part, carrying means for communicating resonant unidirectional vibrations, and shock absorbers of low stiffness, and the means for communicating resonant unidirectional vibrations is made in the form of at least a pair of identical parametric vibration exciters mounted on the reactive part of the machine, installed with the possibility of rotation of rotors of inertial elements in opposite directions in vertical planes and driven in rotation from independent electric motors, and the resonant frequency of means for communicating resonant unidirectional oscillations is determined from the relations ω = λ ₁ + λ ₂ , λ ₁ = v⋅ω, 0 <v <1, where ω is the average value of the partial angular velocities of the rotors, λ ₁ is the effective natural frequency of the swinging pendulums of the rotors of inertial elements, λ ₂ = √ (S / M _pr ) - partial proper frequency of the working body, corresponding to the antiphase form of unidirectional free vibrations, M _pr = M ₁ M ₂ / (M ₁ + M ₂ ) - reduced mass, C - elastic bond stiffness, M ₁ - mass of the working body, M ₂ - total mass of the reactive part cars. The technical result is the achievement of high stability of the resonant mode of operation of the machine with a high quality factor of its oscillatory system, and, as a result, the creation of energy-saving vibration transporting machines.

The disadvantages of this invention are the lack of means for changing the position of the vibration exciter, which does not make it possible to control the dynamic state of the vibration technological machine, as well as to obtain a mode of a single relationship between the coordinates of movement of the vibration technological machine.

The objective of the invention is the formation of a dynamic state of a vibration technological machine by changing the position of the vibration exciter, resting on an elastic support.

A method for correcting the dynamic state of a technological machine, including excitation of vibrations of the working body, characterized in that vibrations are measured, the ratio of vibration amplitudes at different points of the working body and the influence of force effects on the extreme points of the working body are controlled by moving the adjustable vibration exciter along the surface of the vibrating technological machine.

A device for correcting the dynamic state of technological machines includes: a working body resting on supporting elastic elements, a vibration exciter that creates a vibration field, characterized in that the vibration exciter has the ability to move along the surface of the working body in the longitudinal direction and rests on a pneumatic cylinder with adjustable stiffness, which provides opportunities changes in the dynamic state of the technological machine, changing the structure of the vibration field by changing the position of the point of application of the force and the magnitude of the change in the elastic forces of interaction based on information received from the sensors of the dynamic state located at the edges of the working body.

The essence of the invention is illustrated by drawings

FIG. 1 shows a schematic diagram of a vibrating technological machine with devices for adjusting the dynamic state, containing a support surface 1, a working body 2, a control unit 3, elastic elements 4, 5, sensors 6, 7, electric servos 8, 9, lead screws 10, 11, guides 12, support element 13, air spring 14, limiter 15, vibration exciter 16, throttle 17, valve 18, communication links 19, 20, 21, 22, 23, 24.

FIG. 2 shows a design diagram of a technological vibration machine with a spring-loaded vibration exciter.

(координата

исключена).FIG. 3 shows a structural mathematical model of the system of FIG. 2 in coordinates

(coordinate

excluded).

The invention operates as follows. The proposed invention is implemented as a method of forming a vibration field necessary for technological purposes, created by a vibration exciter installed on the lower surface of the working body of the vibration table (or vibration table).

The working body is a plate 2, which is installed on elastic supports 4, 5, which, in turn, rest on a supporting fixed supporting surface 1. A vibration exciter 16 is installed on top of the working body 2, which rests on a pneumatic balloon 14 and is connected to the control unit 3 through a communication communication 23, driven by servo drives 8, 9, having communication links 19, 22 with the control unit 3, and lead screws 10, 11 along the guides 12. The air pressure in the air spring 14 mounted on the support element 13 is regulated by the throttle 17 and valves 18 connected to the control unit 3 containing the compressor through communication links 24, 25. In case of a breakdown of the pneumatic cylinder 14, in order to maintain the uninterrupted operation of the vibration exciter 16, a limiter 15 is provided in the design, onto which, in the event of a malfunction, the vibration exciter 16 is lowered, thereby the mode of its operation with the stiffness of the pneumatic balloon 14 equal to infinity. In this case, there remains one mode of setting the dynamic state, implemented by changing the position of the vibration exciter 16. The operation of the two tuning options provides a wide range of possibilities for obtaining the desired setting mode for the dynamic state.

The control of the dynamic state of the system is carried out in an automatic mode by the control unit 3, which is connected with the dynamic state sensors 6 and 7, which record the vibration amplitudes of the working body 1 along the coordinates y ₁ and y ₂ , through communication links 20, 21.

The dynamic state control system, which works out the algorithm for controlling the movement of the vibration exciter 16 along the guides 12, creates the possibility of changing the force factors along the coordinates y ₁ and y ₂ and makes it possible to obtain various dynamic modes of operation of the vibration technological machine, including the formation of a ratio between the coordinates equal to one.

Theoretical justification

и

от концов рабочего органа (тт. (А), (В)). Особенностью технического объекта является закрепление на рабочем органе дополнительного массоинерционного элемента массой т, совершающего вертикальные колебания под действием гармонической силы Q(t), приложенной к массе m. Упругий элемент дополнительной массы (пружина жесткости k₃) установлен в точке Е, на расстоянии

от центра масс т. О. Фрагмент исходной системы в виде массоинерционного элемента m и пружины k₃ отражает локальные свойства вибровозбудителя колебаний технологической вибрационной машины. Между системами координат технического объекта существуют отношения:In many cases, a technological vibration machine can be represented in the form of a mechanical vibrational system having an extended rigid body with mass M and moment of inertia J, and resting on elastic elements (springs with stiffness k ₁ and k ₂ ) (Fig. 2). A rigid body (or a working body) performs oscillatory movements in coordinate systems y ₁ , y ₂ or y ₀ , ϕ, associated with a fixed basis. The center of mass of the system (m. O) is located at distances

and

from the ends of the working body (vols. (A), (B)). A feature of the technical object is the attachment of an additional mass-inertial element of mass m to the working body, which performs vertical oscillations under the action of a harmonic force Q (t) applied to the mass m. The elastic element of additional mass (spring of stiffness k ₃ ) is installed at point E, at a distance

from the center of mass of the t. O. A fragment of the original system in the form of a mass-inertial element m and a spring k ₃ reflects the local properties of the vibration exciter of vibrations of a technological vibration machine. There are relationships between coordinate systems of a technical object:

(в дальнейшем используется

Where

(further used

To compose a system of equations of motion, techniques are used based on the application of the Laplace transforms with zero initial conditions

The coefficients of the system of equations of motion of a technical object (Fig. 1) in operator form are given in Table. 1.

- комплексная переменная; значок 〈-〉 над переменной означает ее изображение по Лапласу.Note:

- complex variable; the 〈-〉 icon above a variable means its Laplace image.

.The system of differential equations (2) ÷ (4) can be simplified to solve problems associated with the estimation of the features of the distribution of the vibration amplitudes of the points of the working body along its length

...

получим, учитывая значение коэффициентов

из таблицы выражения для передаточных функций W₁(p), W₂(p), W₃(p) при действии входного возмущения

I. Features of constructing a mathematical model of the original system in a simplified form. Localization on the design scheme (Fig. 2) of an additional solid body of mass m, resting on an elastic element of stiffness k ₃ , in contact at point E with the working body (M, J), in essence, can be interpreted as an attachment at point E of a dynamic vibration damper. If we use Cramer's rules, then the transfer functions of the system under external disturbance

we obtain, taking into account the value of the coefficients

from the table of expressions for the transfer functions W ₁ (p), W ₂ (p), W ₃ (p) under the action of an input disturbance

Where

- is the frequency characteristic equation of the system.

,

From (8) it follows, in particular, that the system has three resonance frequencies. At the same time, dynamic vibration damping modes are possible in the system. The corresponding expressions for determining the frequencies of dynamic damping of oscillations can be obtained on the basis of expressions for transfer functions (5) ÷ (7) by coordinates

,

, являются корнями следующего биквадратного уравнения:in turn, the vibration damping frequencies along the coordinate

, are the roots of the following biquadratic equation:

может дважды принимать нулевые значения.With the introduction of an additional constraint in the form of a loaded rigid body of mass m at point E, the coordinate

can be zero twice.

II. Dynamic damping of vibrations at the point of contact of the additional connection with the surface of the working body of the technological machine.

в соответствии с соотношением (1) определяется выражениемCoordinate

in accordance with relation (1) is determined by the expression

, то (12) преобразуется к виду:Insofar as

, then (12) is transformed to the form:

Using expressions (5), (6), we find that

может принимать нулевые значения (или проявлять режим динамического гашения колебаний) на одной частоте, значение которой определяется из решения частотного уравнения:Whence it follows that the coordinate

can take zero values (or exhibit a mode of dynamic damping of oscillations) at one frequency, the value of which is determined from the solution of the frequency equation:

or

.Whence it follows that the frequency of dynamic damping of oscillations along the coordinate

...

то есть точка Е выступает в качестве узла колебаний по отношению к трем координатам, что свидетельствует о возможностях проявления нетрадиционных рычажных связей между движениями координат.At the same time, motion is preserved along all three coordinates

that is, point E acts as a node of oscillations in relation to three coordinates, which indicates the possibility of manifestation of unconventional linkages between the coordinate movements.

III. Some questions of simplification of the mathematical model of the system with the exclusion of one of the coordinates. The dynamic properties of the system, the design diagram of which is shown in Fig. 2 does not fundamentally change if point E is located on the lower part of the surface of the working body. In such an arrangement of elements m and k ₂ (and point E) there is a certain sense, since the upper part of the shaker is freed for technological chains, and its lower part becomes available for setting activities.

может быть исключена из системы уравнений (2)÷(4) при использовании следующего подхода. Запишем уравнения (2)÷(4) в видеCoordinate

can be excluded from the system of equations (2) ÷ (4) using the following approach. Let us write equations (2) ÷ (4) in the form

It follows from (20) that

After substituting (21) into equations (18), (19), we obtain a simplified mathematical model in the form of a system of equations

The structural mathematical model can be built on the basis of (22), (23) and has the form, as shown in Fig. 3.

и

. В системе действует два синфазных гармонических фактора, обозначенных на фиг. 3 как

и

. На основе аналогичных подходов в рассматриваемом случае можно также отметить наличие двух парциальных блоков с тем отличием, что они относятся к парциальным системам с двумя степенями свободы.The structural mathematical model (Fig. 3), obtained as a result of equivalent transformations, formally displays the dynamic state using only two coordinates

and

... The system has two in-phase harmonic factors, indicated in FIG. 3 how

and

... On the basis of similar approaches, in the case under consideration, one can also note the presence of two partial blocks, with the difference that they refer to partial systems with two degrees of freedom.

The characteristic frequency equation obtained on the basis of the block diagram shown in FIG. 3 has the form

можно построить передаточные функцииIn coordinate system

you can build transfer functions

To assess the dynamic states formed by the distributions of the amplitudes of the coordinates of the points of the working body of the machine along its length, the transfer function of interpartial connections was introduced

or

After substitution of system parameters from table. 1 we get

or

List of references

1. Ivovich VA .. Vibration isolation of mining and processing machines and equipment. Moscow: Nedra, 1978.252 p.

2. Goncharevich I.F. Theory of vibration technology and technology / I.F. Goncharevich, K.V. Frolov. - Moscow: Nauka, 1981 .-- 319 p.

3. Povidailo V.A. Vibration devices in mechanical engineering. M .; Kiev: Mashgiz. [Yuzh. department], 1962. - 111 p.

Claims (2)

1. A method for correcting the dynamic state of a technological machine, including excitation of vibrations of the working body, characterized in that vibrations are measured, the ratio of vibration amplitudes at different points of the working body and the influence of force effects on the extreme points of the working body are controlled by moving the adjustable vibration exciter along the surface of the vibration technological machine. 2. A device for correcting the dynamic state of technological machines, including a working body resting on supporting elastic elements, a vibration exciter that creates a vibration field, characterized in that the vibration exciter has the ability to move along the surface of the working body in the longitudinal direction and rests on a pneumatic cylinder with adjustable rigidity, which provides the possibility of changing the dynamic state of the technological machine, changing the structure of the vibration field by changing the position of the point of application of the force and the magnitude of the change in the elastic forces of interaction based on information received from the sensors of the dynamic state located at the edges of the working body.

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