RU2548373C2 - Rotor balancing method - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: unbalance is measured, correction action parameters are determined for each correction plane, and weights are corrected, parameters of the correction actions complying with requirement for equality to zero of the residual unbalances in specified correction planes. Then the rotor corrections are determined considering shift of the corrected weight centres from the rated radiuses and planes using simulation of the expected consequences of corrections, then rotor weight is corrected. At that the virtual 3D image of the rotor balance is created, on the virtual rotor the static and instantaneous unbalances are simulated before shift of the main central axis of inertia with axis of rotation. The unbalance parameters are specified, weights are corrected on the virtual reference rotor sample, and virtual correction of the rotor is monitored in the correction planes, and database of the virtual rotor samples is created. Then the balanced rotor is installed in the machine, dynamic pressure is measured in its unbalance supports, unbalances are coincided and compared, and by deviation value the necessity of the rotor balance is determined after deletion of the correcting weight, and as per the minimum residual unbalance of the rotor the balance quality is determined.

EFFECT: increased accuracy of the rotor balancing.

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Description

The invention relates to the field of machine and instrument engineering and is intended for use in technological processes of balancing rotors, can be used in the educational process, providing theoretical and practical training for specialists as balancing operators, as well as training for specialists of any form of training.

There is a known method of balancing rotors, according to which the technological process of balancing is divided into three main transitions: measuring imbalance, converting this information into the amount of unbalanced mass to be eliminated and eliminating unbalanced mass (A.K. Skvorchevsky, E.B. Promyslov. Balancing of rotating masses gyroscopes. Leningrad, ed. "Shipbuilding", 1977, pp. 23-27).

The disadvantage of this method of balancing rotors is its low reliability and accuracy. The specified disadvantage should be compensated by repeated repetition of the balancing cycle, which also increases the complexity of the technological cycle.

A known method of balancing rotors is that imbalances are measured, the parameters of corrective actions for each correction plane are determined and mass correction is performed, the parameters of corrective actions corresponding to the condition of equal to zero residual imbalances in the nominal correction planes are determined taking into account the displacements of the centers of the correcting masses from the nominal ones the radii and planes of the rotor correction through the procedure for modeling the expected consequences of corrective actions, and iteration First, for static balancing, first, for static balancing, the expected residual imbalances are reduced to zero, they are summed up with current imbalances in the corresponding correction plane, and then, for the moment of balancing, the rotor as a whole is reduced to zero the expected equal modulo and opposite residual residuals imbalances, summing them up with current imbalances in each nominal correction plane, after which the rotor masses are adjusted (RF Patent 2163008 IPC: G01M 1/00 published. 10.02. 2001, Bull. Number 4. Chernichkin A.S., Chernichkin A.A. "A method of balancing rotors").

The disadvantage of this method is the low accuracy of the conversion of the measured imbalances, corrective actions, such as: neglect of the resulting displacement of the centers of the correcting masses from the nominal planes and sometimes the rotor correction radii.

This technical solution is selected as a prototype.

The technical result is to increase the accuracy of balancing the rotor by eliminating dynamic imbalance.

массой Δm₁=Δm_max, вторично создают дисбаланс с шагом итерации радиусом (r₂=r₁-Δr с дисбалансом $${\overline{D}}_2$$

) и массой $$\Delta m_2$$

, меньшими при максимальном дисбалансе, задают параметры дисбалансов, осуществляют корректировку масс на виртуальальном эталонном образце ротора и наблюдают за виртуальной корректировкой ротора в плоскостях коррекции, создают базу данных виртуальных образцов роторов, затем устанавливают балансируемый ротор на станок и измеряют динамическое давление в опорах его неуравновешенности, совмещают и сравнивают дисбалансы, а по величине отклонения судят о необходимости балансировки ротора, удалив корректирующую массу и по минимальному остаточному дисбалансу ротора судят о качестве балансировки. Способ поясняется чертежами.The technical result is achieved by the fact that in the method of balancing the rotors, namely, that imbalances are measured, the parameters of the corrective actions for each correction plane are determined and the masses are adjusted, the parameters of the corrective actions corresponding to the condition of equal to zero residual imbalances in the nominal correction planes are determined taking into account the displacements of the centers of the correcting masses from the nominal radii and planes of the rotor correction through the procedure for modeling the expected consequences of stimulating effects, and iterative calculation first, for static balancing, they achieve successively in each nominal plane of correction the reduction to zero of the expected residual imbalances, summing them with the current imbalances in the corresponding correction plane, and then for the momentary balancing, they achieve for the rotor as a whole to bring the expected equal to zero modulus and opposite residual imbalances, summing them with current imbalances in each nominal correction plane, and then produce to adjustment of the mass of the rotor, then create a virtual three-dimensional image of the balancing of the rotor, simulate the static and momentary imbalances on the virtual rotor to align the main central axis of inertia with the axis of rotation, creating a virtual grid diagram with an external circle of radius r ₁ = r _max at maximum imbalance $${\overline{D}}_{\mathrm{one}}=\overline{D}\max$$

mass Δm ₁ = Δm _max , secondly create an imbalance with an iteration step of radius (r ₂ = r ₁ -Δr with imbalance $${\overline{D}}_2$$

) and mass $$\Delta m_{}$$$${}_2$$

that are smaller at the maximum imbalance, set the imbalance parameters, carry out mass correction on the virtual reference rotor sample and observe the virtual correction of the rotor in the correction planes, create a database of virtual rotor samples, then install a balanced rotor on the machine and measure the dynamic pressure in the supports of its imbalance, imbalances are combined and compared, and the magnitude of the deviation is judged on the need to balance the rotor, removing the corrective mass and the minimum remaining The rotor imbalance is judged on the quality of the balancing. The method is illustrated by drawings.

Figure 1 presents a three-dimensional image of the rotor by rotating a flat image.

Figure 2 presents the balancing circuit of the rotor.

The rotor balancing method is implemented by the device, where 1 is the balancing rotor, 2 is the rotor balancing process control device, 3 is the balancing process simulation block, 4 is the comparison block, 5 is the simulation results output block, 6 is the correction block, 7 is the imbalance angle measurement sensor and rotor revolutions, 8, 9 - force sensors of the left and right bearings, respectively, 10 - machine for balancing the rotor.

The balancing method is as follows.

Create a virtual image of a reference sample of the rotor, for example, by scanning with optical laser equipment or by rotating the flat section of the rotor in X-Y coordinates. When the elementary volume shown in the form of points of FIG. 1 rotates around the fixed axis of the turbine rotor, each elementary volume ΔV _i (mass) describes circles whose centers are on one straight line perpendicular to the planes of these circles. The straight line itself is the axis of rotation of the turbine rotor. Each elementary volume as material points passes over time Δt different paths. So arc AA ₁ > arc BB ₁ , therefore, the modulus of speed of point A is greater than point B. Moreover, the radii r _{1 of the} circles rotate in time Δt _i by the same angle φ. If this angle is precisely determined between two beams extending from one point of the rotor axis and perpendicular to it, let the beam OX be stationary in space and the beam OA be rigidly connected with the elementary volume ΔV _i .

. Если угловую скорость выразить через число оборотов ротора, т.е. число полных оборотов за 1 с, а ротор делает n оборотов 1 с, то время одного оборота равно $$T=\frac{1}{n}$$

, что соответствует полному обороту на угол φ=2π. Отсюда угловая скорость определяется равенством $$\omega =\frac{2\pi }{T}=2\pi n$$

.Let the rotor rotate evenly. The rotor speed is determined by the angle of rotation of any beam associated with the elementary volume for a given time interval and is characterized by the angular velocity $$\omega =\frac{\Delta \varphi }{\Delta t}$$

. If the angular velocity is expressed in terms of the rotor speed, i.e. the number of full revolutions in 1 s, and the rotor makes n revolutions 1 s, then the time of one revolution is $$T=\frac{\mathrm{one}}{n}$$

, which corresponds to a full revolution by an angle φ = 2π. Hence the angular velocity is determined by the equality $$\omega =\frac{2\pi }{T}=2\pi n$$

.

If during uniform rotation of the rotor the angular velocity is known and at the initial moment of time t ₀ = 0 the rotation angle is φ ₀ = 0, then the rotation angle of the elementary volume (material point) over time t is equal to φ = ω · t, from this we can find the position of the elementary volume of the rotating the rotor at any time and determine the place of imbalance of the rotor, which is the basis of the method of imbalance.

, на который действует центробежная сила инерции $${\overline{F}}_i$$

, определяемая равенствомWhen the rotor 1 rotates around its axis of rotation, a centrifugal inertia force acts on each elementary volume ΔV _{t of} mass Δm _i . Each elementary volume describes a circle of radius $${\overline{r}}_{\Delta m_i}$$

affected by centrifugal inertia $${\overline{F}}_i$$

defined by equality

$${\overline{F}}_i=m{a}_n=\Delta m_i{\omega }^2{\overline{r}}_{\Delta m_i},\text{(one)}$$

изменяется по направлению и оказывает вибрационное воздействие на опоры через них - на всю конструкцию ротора, что приводит к износу кинематических пар, повышению усталостной прочности деталей, к появлению вибрации звеньев кинематических схемы.When moving the mass Δm _i force $${\overline{F}}_i$$

changes in direction and exerts a vibrational effect on the supports through them — on the entire rotor structure, which leads to wear of the kinematic pairs, an increase in the fatigue strength of the parts, and to the appearance of vibration of the links of the kinematic scheme.

Imbalance and its manifestation. The eccentricity e of the mass m is the radius vector of the center of this mass relative to the axis of rotation and is measured in millimeters. An imbalance D is a vector quantity equal to the product of mass m and its eccentricity and is measured in gram millimeters:

, $$\overline{D}=m\overline{e}\text{(2)}$$

,

и ē по направлению совпадают и называются коллинеарными, то выражение (1) можно записать в векторном виде:If the vectors $$\overline{D}$$

and ē in direction coincide and are called collinear, then expression (1) can be written in the vector form:

$$\overline{F}={\omega }^2\left(m\overline{e}\right)={\omega }^2\overline{D}.\text{(3)}$$

неуравновешенной силы инерции пропорционален вектору дисбаланса $$\overline{D}$$

. Угол φ называется углом дисбаланса D в системе координат, связанных с вращающимся телом.Vector $$\overline{F}$$

unbalanced inertia is proportional to the imbalance vector $$\overline{D}$$

. The angle φ is called the imbalance angle D in the coordinate system associated with the rotating body.

The static imbalance of the rotor is characterized by such a distribution of its masses that the axis of rotation of the rotor and its main central axis of inertia are parallel. The presence of static imbalance is easy to detect. To do this, it is enough to put the rotor on horizontal prisms (“knives”). Under the influence of gravity, the rotor will tend to a stable equilibrium position when its center of mass S occupies a lower position: i.e. on knives the rotor will turn.

. Силу инерции $${\overline{F}}_u$$

определим по формуле:When a statically unbalanced rotor rotates, the inertia force leads to the main vector $${\overline{F}}_u$$

. Inertia force $${\overline{F}}_u$$

define by the formula:

где m - масса ротора; $$F_u=m{a}_s=m\sqrt{{(a_s^n)}^2+{(a_s^{\tau })}^2}=\sqrt{{({\omega }^2{e}_s)}^2+{(\epsilon e_s)}^2}=m{\mathrm{<figure-callout\; id="2"\; label="e\; s\; \omega "\; filenames="00000031.png"\; state="\{\{state\}\}">e\; </figure-callout>}}_s\sqrt{{\omega }^{}}\sqrt{{}^2+{\mathrm{<figure-callout\; id="2"\; label="\epsilon "\; filenames="00000031.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}^2}=\mathrm{<figure-callout\; id="2"\; label="D\; \omega "\; filenames="00000031.png"\; state="\{\{state\}\}">D\; </figure-callout>}\sqrt{{\omega }^{}}\sqrt{{}^2+{\mathrm{<figure-callout\; id="2"\; label="\epsilon "\; filenames="00000031.png"\; state="\{\{state\}\}">\epsilon </figure-callout>}}^2},\text{(four)}$$

where m is the mass of the rotor;

a _s is the acceleration of the center S of the mass of the rotor;

ω, ε - angular velocity and angular acceleration of the rotor.

создает динамические давления в опорах ротораForce $${\overline{F}}_u$$

creates dynamic pressure in the rotor bearings

$$R_A=F_u\frac{b}{a+b}\text{;}{R}_B=F_u\frac{a}{a+b}.\text{(5)}$$

From the expression (5) it follows that the variable pressure forces acting in the supports will be zero under the condition:

Thus, in a statically balanced rotor, its axis of rotation must pass through the center of mass of the rotor, i.e. to be the central axis.

The momentary imbalance of the rotor is characterized by such a distribution of its masses that the axis of rotation of the rotor and its main central axis of inertia intersect at the center of mass of the rotor. Since the center of mass of the rotor with momentary imbalance is on the axis of rotation, the rotor mounted on the “knives” will be in an indifferent equilibrium position. Therefore, it is impossible to detect momentary imbalance on knives.

This imbalance manifests itself during rotation of the rotor: the inertial forces of its masses are reduced to the main moment of the inertia forces

$$M_u=\sqrt{{\omega }^{\mathrm{four}}+{\epsilon }^{\mathrm{four}}}\cdot \sqrt{{\mathrm{<figure-callout\; id="2"\; label="J\; y\; z"\; filenames="00000031.png"\; state="\{\{state\}\}">J\; </figure-callout>}}_{yz}^{}+{\mathrm{<figure-callout\; id="2"\; label="J\; x\; z"\; filenames="00000031.png"\; state="\{\{state\}\}">J\; </figure-callout>}}_{xz}^{}},\text{(7)}$$

where J _yz , J _xz are the centrifugal moments of inertia of the mass of the rotor in the coordinate system xyz associated with the rotor;

z is the axis of rotation of the rotor;

ω is the angular velocity of the rotor;

ε is the angular acceleration of the rotor.

The unbalanced moment M _u creates a dynamic pressure in the rotor bearings:

$$R_A=R_B=\frac{M_u}{l},\text{(8)}$$

where M _u is the moment of inertia forces;

l is the length of the supports.

From the expressions (7) and (8) it follows that the pressure variables in the bearings will be equal to zero, provided that the centrifugal moments of inertia of the masses of the rotor are also equal to zero

$$J_{yz}={\displaystyle \underset{(M)}{\int }dm\cdot y\cdot z=0},J_{xz}={\displaystyle \underset{(M)}{\int }dm\cdot x\cdot z=0},\text{(9)}$$

where xyz - coordinates of the elementary mass dm associated with the rotor;

M is the mass of the rotor.

It can be seen from this that the condition of expression (9) is only possible for the main axes of inertia, then to eliminate the momentary imbalance of the rotor, it is necessary to redistribute the mass of the rotor so that its axis of rotation becomes the main axis of inertia. The most common case of rotor imbalance is a dynamic imbalance consisting of static and momentary imbalances.

Thus, in all cases, if the rotor is unbalanced, the inertial forces of its masses create dynamic loads in the supports. These loads can be eliminated due to the redistribution of rotor masses - installation of corrective masses (balances). Rotor balancing is an exception method.

A perfectly balanced rotor will transmit to its supports and further to the frame only static loads from its own weight, i.e. a rotating rotor will have the same effect on the bearings as a stationary one. The fulfillment of the conditions of expressions (6) and (9) of the dynamic balancing of the rotor can be carried out using two correction masses that are set or removed in the correction planes. These planes should be perpendicular to the axis of rotation of the rotor. Dynamic balancing of the rotor can be performed, for example, on a machine for dynamic balancing.

массой Δm₁=Δm_max с шагом итерации до минимального дисбаланса. Затем по радиусу r₂=r1-Δr С дисбалансом $${\overline{D}}_2$$

массой Δm₂, до окружности радиусом r_ост с остаточным дисбалансом $${\overline{D}}_{ост}$$

массой Δm_ост и шагом по углу один градус, начиная от метки угла φ₀=0°, φ_i с шагом 1° до 360°. Моделируют параметры дисбалансов путем изменения оборотов ротора в пределах n_min÷n_max, величину некорректированной массы, ее объем, координаты и динамические давления на опорах. Результаты моделирования наблюдают на экране монитора. Корректировку масс осуществляют на виртуальальном эталонном образце ротора и наблюдают на экране монитора виртуальную корректировку ротора в плоскостях коррекции. Затем балансировку ротора по заявляемому способу осуществляют на станке для балансировки. Для определения параметров корректирующей массы m_к в плоскостях коррекции ротор 1 устанавливают на станок 10 (фиг.2). Заставив ротор вращаться, измеряют силы давления с помощью датчика 8 на левой и датчика 9 на правой опоре, возникающие из-за дисбаланса. Одновременно измеряют угол дисбаланса и обороты ротора с помощью датчика 7. Информацию от датчиков 7-9 преобразовывают в электрические сигналы, которые поступают в устройство управления процессом балансировки 2, в котором моделируют процесс балансировки в блоке моделирования 3. Результаты моделирования из блока 3 поступают на вход блока сравнения 4, в котором результаты моделирования дисбаланса сравнивают с техническими условиями. Дисбалансы балансируемого ротора совмещают с виртуальными неуравновешенностями и по величине совместимости судят о необходимости балансировки ротора или годности.The method is implemented on a machine for dynamic balancing of rotors (figure 2) as follows. At the first stage, simulation of the conditions for the occurrence of vibrations or dynamic pressure on the supports of the virtual rotor is carried out using a mathematical model, while there is a methodological error. Input of the initial data includes the main operational indicators of the rotor: weight, geometric dimensions, operating modes, the magnitude of the allowable imbalance. If you immediately measure the angle of imbalance, then in this case, the methodological error is excluded. The program for controlling the process of modeling static, momentary and dynamic imbalance is responsible for organizing the processing of primary information for a given imbalance, calculating the parameters that determine the imbalance: mass and volume, coordinates in each correction plane, as well as unbalance elimination schemes. At the same time, the balancing operator, mastering the balancing technique on the virtual rotor, carries out mass correction on it in the correction planes. The results of virtual balancing are observed on a grid diagram with an outer circle of radius r ₁ = r _max at maximum imbalance $${\overline{D}}_{\mathrm{one}}={\overline{D}}_{\max }$$

mass Δm ₁ = Δm _max with an iteration step to the minimum imbalance. Then, along the radius r ₂ = r1-Δr With imbalance $${\overline{D}}_2$$

mass Δm ₂ , to a circle of radius r _ost with residual imbalance $${\overline{D}}_{\mathrm{about}\mathrm{from}t}$$

mass Δm _ost and a step in the angle of one degree, starting from the angle mark φ ₀ = 0 °, φ _i in increments of 1 ° to 360 °. Imbalance parameters are simulated by changing the rotor speed within n _min ÷ n _max , the value of the uncorrected mass, its volume, coordinates and dynamic pressure on the supports. Simulation results are observed on a monitor screen. Mass correction is carried out on a virtual reference rotor sample and virtual rotor correction in the correction planes is observed on the monitor screen. Then, the balancing of the rotor according to the claimed method is carried out on a machine for balancing. To determine the parameters of the corrective mass m _to in the correction planes, the rotor 1 is installed on the machine 10 (figure 2). After making the rotor rotate, pressure forces are measured using a sensor 8 on the left and a sensor 9 on the right support, arising from imbalance. At the same time, the imbalance angle and the rotor speed are measured using the sensor 7. The information from the sensors 7-9 is converted into electrical signals that enter the balancing process control device 2, in which the balancing process is simulated in simulation block 3. The simulation results from block 3 are input block comparison 4, in which the results of the simulation of the imbalance is compared with the technical conditions. The imbalances of the balancing rotor are combined with virtual imbalances and, by the magnitude of compatibility, they judge the need for balancing the rotor or shelf life.

,The comparison results are related by. If the condition is met $${\overline{D}}_{\min }={\overline{D}}_{\mathrm{about}\mathrm{from}t}\left(B.R.\right)<\frac{{\overline{D}}_{\mathrm{about}\mathrm{from}t}\left(B.R.\right)}{\mathrm{TO}}$$

,

- остаточный дисбаланс балансируемого ротора,Where $${\overline{D}}_{\mathrm{about}\mathrm{from}t}\left(B.R.\right)$$

- residual imbalance of the balanced rotor,

- минимальный остаточный дисбаланс балансируемого ротора, $$\overline{D}\min \left(B.R.\right)$$

- minimum residual unbalance of the balanced rotor,

K = 2 ÷ 5 - constant coefficient characterizing the quality of balancing,

then the “Good” rotor and the results are displayed in the block for issuing simulation results 5. If the condition is not fulfilled, information about this goes to the correction block 6, where the value of the uncorrected mass is calculated, a drawing is printed indicating its location. From the output of the correction unit 6, the information goes to the machine 10 and the balancing process of the rotor 1 is repeated.

The system has good visibility not only of the elements of virtual balancing, but of individual elements of the system itself. Visual observable elements should be visual, the system has the ability to enlarge the size of the balancing points, a bright contrasting color of the mechanical balancing parts.

The proposed method in comparison with the prototype is more effective due to the expansion of its functionality, increasing accuracy and eliminating methodological errors during balancing. The software provides for the use of effective screen images.

The balancing method based on the virtual rotor and machine allows for rapid research by modeling and measuring the parameters of various types of imbalances: static, momentary and dynamic. The advantage of this method is the high measurement speed. The time of measuring imbalances is not more than 5 ÷ 10 minutes, the time of mechanical removal is not more than 5 minutes. The high speed of eliminating the imbalance is determined by the accuracy of the drawing for the balancing operator and the machining technology.

Claims (1)

The method of balancing the rotor, namely, that imbalances are measured, the parameters of corrective actions for each correction plane are determined and the masses are adjusted, the parameters of corrective actions corresponding to the condition of equal to zero residual imbalances in the nominal correction planes are determined taking into account the displacements of the centers of the correcting masses from the nominal radii and rotor correction planes through the procedure for modeling the expected consequences of corrective actions, and iterative calculation In the summer, first, for static balancing, they achieve successively in each nominal plane of correction the reduction to zero of the expected residual imbalances, summing them with current imbalances in the corresponding correction plane, and then, for momentary balancing, they achieve for the rotor as a whole to bring to zero the expected equal in absolute value and opposite residual imbalances , summing them up with the current imbalances in each nominal correction plane, after which the rotor mass is adjusted, characterized in that about create a virtual volumetric image of a balanced rotor, simulate static and momentary imbalances on a virtual rotor to combine the main central axis of inertia with the axis of rotation, creating a virtual grid diagram with an outer circle of radius r_one= r_max at maximum imbalance

 Δm_one= Δm_max and for the second time create an imbalance with a radius and mass smaller at the maximum imbalance, then set the imbalance parameters that carry out the mass correction on the virtual reference rotor sample and observe the virtual rotor correction in the correction planes, creating a database of virtual rotor samples, then set up a balanced rotor on the machine and measure the dynamic pressure in the supports of its imbalance, compare its imbalances with virtual imbalances on the database of virtual the rotors and the deviation are judged on the need for balancing the rotor, removing the corrective mass, and the minimum residual imbalance of the rotor is judged on the quality of the balancing.

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