RU2016384C1 - Method of determining unbalance vector parameters - Google Patents

Abstract

FIELD: balancing rotating parts and assemblies of machines. SUBSTANCE: method involves the steps of: placing article 2 to be balanced and two identical unbalance vibration exciters 3 and 4 with unbalance m_uε_u on shock-proof base 1, arranging their rotation axes in a plane passing through a center of mass of the base, a rotation axis of article 2 being located in the center of mass of base 1 and the vibration exciters being located symmetrically with respect to the article rotation axis; applying mark 8 corresponding to location of unbalance onto of the vibration exciters, applying mark 9 onto the article as well, driving the article and vibration exciters into synchronous rotation with the aid of electric induction motors; recording signals from marks 8 and 9 and measuring amplitude r_o of oscillations of the base, measuring angle α_mε of the article unbalance location relative to mark 9 in the direction of rotation of the article and determining an angle value from the expression given in the invention description. EFFECT: enhanced accuracy in determining unbalance vector parameters due to excluded error caused by rotation nonuniformity of article 2 being balance. 2 dwg

Description

 The invention relates to a balancing technique and can be used to determine the magnitude of the unbalanced mass and the phase angle of imbalance when balancing rotating parts and components of machines and mechanisms.

 A known method for determining the parameters of the imbalance vector, which consists in measuring and recording the radial displacement signal of a rotating body, and the imbalance is judged by the parameters of the signal.

 A known method of measuring the parameters of the imbalance vector of rotating bodies, which consists in measuring and recording the signal of the maximum radial movement of the body, determine the phase angle of the imbalance relative to the mark applied to the said body.

 A disadvantage of the known methods is the appearance of a measurement error caused by the superposition of the signal from the non-circularity of the surface being monitored on the signal from imbalance.

 A known method for determining the parameters of the imbalance vector, which consists in the fact that a number of evenly spaced reference marks are applied to the surface of the body, in the static mode, compensating signals for the non-circularity of the body are measured, in the dynamic mode they measure the signals of radial displacement, determine the differences of the mentioned signals and use them to determine the imbalance, moreover, signals from an uncontrolled surface are blocked.

 The disadvantage of this method is that to increase the accuracy of measuring the amplitude and imbalance angle, it is necessary to increase the number of marks, while the complexity of the method increases significantly. In addition, the accuracy of measuring the imbalance parameters of this method is limited by the inertia of the measuring system and the appearance of interference with a small pitch of the labels. Moreover, the accuracy of determining the parameters of the imbalance vector is ensured only for the controlled surface of the body, made in the form of a circle. For rotating bodies having a discontinuous surface (for example, gears), the indicated imbalance parameters can be determined with a large error.

 A known method for determining the angle of imbalance of the rotor, which consists in magnetizing the balanced product around the circumference by a sequence of pulses, the first of which has a negative, and the rest has a positive polarity at a low speed of rotation of the product. The imbalance angle is determined at the operating rotation speed by the number of detected pulses of positive polarity located between the negative polarity pulse and the "hard spot" of the product being balanced.

 The method has the following disadvantages. The accuracy of the method is determined by the number of pulses in the sequence that magnetize the surface of the balanced product. Due to the fact that a special operation is used for magnetization when the product is rotated at low speed, the known method has a high complexity. A number of products (for example, plastic gears) are not magnetizable, which narrows the scope of the known method.

 The closest in technical essence is the method of determining the parameters of the imbalance vector, which consists in installing the balanced product on a shock-absorbing base, bringing the product into rotation by measuring the parameters of the base vibrations.

 The disadvantages of this method are as follows. The parameters of the imbalance vector are determined by measuring the vibration parameters of the base during rotation of the balanced product. Errors in the elements of the drive for rotating the product, frequency and voltage variations of the electric current used to power the drive electric motor, lead to uneven rotation of the product. As a result, the measured signal is the sum of the following signals: the main signal due to the imbalance of the product; signal component due to uneven rotation of the product due to the presence of errors in the drive elements; component of the signal due to errors in the measuring system. Due to the fact that the determination of the parameters of the imbalance vector is based on the analysis of the mentioned signal, the known method has insufficient accuracy.

 The aim of the invention is to improve the accuracy of determining the parameters of the imbalance by eliminating the error caused by the uneven rotation of the product.

_{> 2}, где J - главный центральный момент инерции основания относительно оси вращения изделия;
r - расстояние от центра масс основания до осей вращения дебалансов вибровозбудителей.This goal is achieved by the fact that two identical unbalanced exciters are placed on the base symmetrically with respect to the axis of rotation of the balanced product so that the axis of rotation of the unbalances of the vibration exciters and the balanced product are located in the same plane passing through the center of mass of the base, the axis of rotation of the balanced product is combined with the axis passing through the center of mass of the base, on one of the vibration exciters a mark is applied corresponding to the location of its imbalance, a mark is applied to the balanced product the balanced product and vibration exciters are brought into synchronous rotation, the signals from the two mentioned marks are recorded, the amplitude of its circular translational vibrations is taken as the base vibrations, the angle of the product unbalance relative to the mark is counted in the direction of rotation of the balanced product, its value is determined by the formula
α _mε = (α _o -α _d ) - 180 ^о , where (α _o -α _d ) is the phase shift of the signal α _o marks on the balanced product relative to the signal α _d marks on the vibration exciter; the imbalance of the balanced product is determined by the formula
m ε = 2m _d ε _d - r _о M, where r _о is the amplitude of the circular translational vibrations of the base;
M is the mass of the base and inertial elements of vibration exciters;
m _d ε _d - the imbalance of one vibration exciter, and the base parameters are selected from the condition

_{> 2} , where J is the main central moment of inertia of the base relative to the axis of rotation of the product;
r is the distance from the center of mass of the base to the axis of rotation of the unbalance of vibration exciters.

Using the proposed method provides the determination of the parameters of the imbalance vector of the product with synchronous movement of the product and unbalanced vibration exciters, i.e. when establishing a phase shift between them equal to 180 ^about . Observance of the synchronization condition ensures the stability of the phase shift, i.e. independence of the magnitude of the shift from fluctuations in the speed of rotation of the product and rotors of unbalanced vibration exciters due to errors in the elements of the drive of rotation. As a result, the error of the measured signal due to the uneven rotation of the product is eliminated, which leads to an increase in the accuracy of determining the parameters of the imbalance vector.

 In FIG. 1 shows a diagram of a method; figure 2 - scheme for determining the angle of imbalance.

_{> 2}, где М - масса основания и инерционных элементов возбудителей;
J - главный центральный момент инерции основания относительно оси вращения изделия;
r - расстояние от центра масс основания до осей вращения дебалансов вибровозбудителей. На одном из дебалансных возбудителей, например на возбудителе 3, наносят метку 8, соответствующую расположению дисбаланса; наносят метку 9 на изделие 2 или на тело, неподвижное относительно изделия 2 (например, диск 10). Дебалансные вибровозбудители 3 и 4 и изделие 2 приводят в синхронное вращение (т.е. вращение с равными угловыми скоростями и в одном и том же направлении). Привод осуществляется от асинхронных электродвигателей 5, 6 и 7.The product 2 and two identical unbalanced vibration exciters 3 and 4 are placed on the shock-absorbing base 1 (see FIG. 1). Under the shock-absorbing base we mean a body whose parameters correspond to the following condition: p / ω << 1, p is the frequency of free vibrations of the base, ω - angular velocity of unbalanced vibration exciters. The axis of rotation of the product 2 is located in the center of mass of the base 1, the vibration exciters 3 and 4 are located symmetrically to the axis of rotation of the product 2, and the axis of rotation of the unbalance of the vibration exciters 3 and 4 and the product 2 are located in the same plane passing through the center of mass of the base. The parameters of the base are determined based on the following condition

_{> 2} , where M is the mass of the base and inertial elements of the pathogens;
J is the main central moment of inertia of the base relative to the axis of rotation of the product;
r is the distance from the center of mass of the base to the axis of rotation of the unbalance of vibration exciters. On one of the unbalanced pathogens, for example on the pathogen 3, put a label 8, corresponding to the location of the imbalance; mark 9 is applied to the product 2 or to a body stationary relative to the product 2 (for example, disk 10). The unbalanced vibration exciters 3 and 4 and the product 2 are driven in synchronous rotation (i.e., rotation with equal angular velocities and in the same direction). The drive is carried out from induction motors 5, 6 and 7.

As a result of these operations, the conditions for synchronizing the movements of the product and unbalanced vibration exciters are provided, i.e. the establishment between them of a phase shift of 180 ^° .

The signals from tag 8 are recorded using sensor 11 (signal A in FIG. 2) and tags 9 using sensor 12 (signal B in FIG. 2). The amplitude r _{о of the} circular translational vibrations of the base 1 is measured, for example, using inductive sensors 13 and 14. The angle of imbalance α _{mε of the} product 2 relative to the mark 9 applied to it is counted along the rotation of the product, and the angle α _mε is determined by the formula
α _mε = (α _o -α _d ) - 180 ^о , (1) where (α _o -α _d ) is the phase shift of signal B of label 9 on the balanced product 2 relative to signal A of label 8 on the vibration exciter 3. The imbalance of the product m ε determined by the formula
m ε = 2m _d ε _d - Mr _o (2) where m _d ε _d is the imbalance of one vibration exciter;
M is the mass of the base and inertial elements of vibration exciters.

 Thus, the calculation of the parameters of the imbalance vector of the product according to formulas (1) and (2) allows to increase the accuracy of determining the parameters of the imbalance vector due to compliance with the measurement of the conditions of synchronous movement of the product and unbalanced pathogens.

 The method is implemented as follows.

 The parameters of the grinding wheel unbalance vector were determined to cut diamond crystals.

 The grinding wheel was mounted on the rotor, the axis of rotation of which passed through the center of the mass-movable platform mounted on elastic supports. Symmetrically to the axis of rotation of the grinding wheel, two identical unbalanced vibration exciters were installed. The axis of the vibration exciters was placed in the same plane with the axis of rotation of the grinding wheel passing through the center of mass of the platform. The surface of the rotor of the unbalanced vibration exciter and the mandrel of the rotor of the grinding wheel were marked. The unbalanced vibration exciters and the grinding wheel are rotated at equal angular speeds and in one direction. As drive motors used asynchronous motors 4AHUT7182. Signals from the tags were recorded using non-contact inductive sensors of the TsIP-2 device (digital displacement meter). The amplitude of the circular translational vibrations of the platform was measured using the TsIP-2 device.

 The main parameters of the method are given in the table.

 Thus, to determine the angle of the imbalance of the product, it is sufficient to register the phase shift of the signals from two labels, one of which is applied to the product, the other to the rotor of one of two identical vibration exciters. To determine the magnitude of the imbalance, it is enough to measure one quantity - the amplitude of the circular translational vibrations of the amortized base. As a result, when using the proposed method provides high accuracy in determining the parameters of the imbalance vector.

Claims (1)

The METHOD FOR DETERMINING THE PARAMETERS OF THE UNBALANCE VECTOR, namely, that the balanced product is mounted on a shock-absorbing base, the balanced product is rotated and the base vibrations are measured, characterized in that, in order to increase accuracy, two identical unbalanced vibration exciters are placed on the base symmetrically with respect to the axis of rotation of the balanced products so that the axis of rotation of the unbalance of vibration exciters and the balanced product are located in the same plane passing through the center of mass of the main The axis of rotation of the balanced product is combined with the axis passing through the center of mass of the base, a mark corresponding to the location of its imbalance is applied to one of the vibration exciters, a mark is applied to the balanced product, the balanced product and vibration exciters are brought into synchronous rotation, signals from the two mentioned marks are recorded, as the base vibrations take the amplitude of its circular translational vibrations, the angle of the imbalance of the product relative to the mark is counted in the direction of rotation of the ba ansiruemogo product, its size is determined by the formula
α _mε = (α _о - α _д ) - 180 ^o ,
where (α _about - α _d ) is the phase shift of the signal α _{about the} labels on the balanced product relative to the signal α _d tags on the vibration exciter,
the imbalance of the balanced product is determined by the formula
mε = 2m _d ε _d - r _о M,
where r ₀ is the amplitude of the circular translational vibrations of the base;
M is the mass of the base and inertial elements of vibration exciters,
m _d ε _d - the imbalance of one vibration exciter,
and the base parameters are selected from the condition

_{> 2} ,
where I is the main central moment of inertia of the base relative to the axis of rotation of the product;
r is the distance from the center of mass of the base to the axis of rotation of the unbalance of vibration exciters.

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