RU2382999C1 - Method for dynamic balancing of rotor - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention is related to balancing equipment and may be used to detect and correct unbalance of rigid rotors. Method consists in the fact that vertically installed unbalanced rotor, being in mode of angular oscillations, simultaneously makes an even rotation around its axis by angle of not more than φ_max=181 degree to the moment when maximum value of oscillations amplitude appears versus horizontal axis, arising from unbalanced inertia forces. At the same time initially one of reduction planes is matched with horizontal axis, relative to which oscillations occur that arise from action of tangential components of unbalanced inertia forces. Such arrangement of rotor will eliminate effect of this plane unbalance at result of this stage measurement. After detection and elimination of unbalance in this plane, rotor moves in axial direction by a fixed distance, and measurements are repeated.

EFFECT: increased accuracy of rotor unbalance parametres measurement, expansion of method application field.

2 cl, 3 dwg

Description

The present invention relates to techniques for dynamically balancing bodies of revolution and can be used to determine the imbalance of rigid rotors.

The method of balancing rigid rotors involves measuring the parameters of unbalance (the value of the unbalanced mass, radius, and angle of its center relative to the axis of the rotor) by determining in the general case two unbalance vectors that lie in two arbitrary planes perpendicular to the axis of the rotor.

Known methods for balancing rotors [1], in which to determine the parameters of imbalance, the rotor is rotated around an axis.

To determine the instability parameters in the dynamic mode, the oscillations of the rotor axis or dynamic reactions in the supports are measured. The amplitude of these oscillations or reactions under certain conditions is proportional to the magnitude of the imbalance, and their phase shift relative to the start of measurements (or the reference signal) indicates the angular coordinate of its location. According to the data obtained, the main vector and the main moment of the imbalance are determined, which, according to the known relations [1], can be replaced by an equivalent circuit consisting of two imbalances located in two arbitrary planes perpendicular to the rotor axis and called the unbalance reduction planes.

The methods of balancing during rotation are distinguished by the modes (pre-resonance, resonance and resonance) and the types of mechanical systems used balancing devices that are classified by the number of degrees of freedom and the number of degrees of freedom of the rotor.

A known method of balancing the rotor, based on the message to the rotor installed in the bearings, rotational motion. A distinctive feature of this method is that to separate the imbalances in the planes of reducing the rotor imbalance after measuring the vibration parameters at one position of the rotor, it is rotated 180 ° and the amplitude and phase of the rotor vibrations are measured again, after which the received data are processed, calculating the imbalance in each from the planes of reduction of imbalance [2]. The disadvantages of this method are the high complexity and low productivity.

A known method of dynamic balancing of a rotor with two reduction planes during its rotation [3], in which one of the planes is combined with the swing axis of the frame. They rotate the rotor, accelerate it to a frequency higher than the resonant one, turn off the drive and measure coastal imbalance in a plane that does not coincide with the swing axis. After reducing the speed below resonance, the pressure in the support is re-measured, by which the imbalance of the other plane is determined.

The disadvantages of this method are the difficulties with the separation of signals from various imbalances in different alignment planes, the relatively low productivity associated with the need to accelerate and decelerate the rotor, high dynamic loads on the rotor itself, which excludes the use of this method when balancing easily destroyed rotors, high energy costs and fundamental the inability to automate the balancing process.

Of the known closest in technical essence is the method of balancing the rotors [4], according to which the balanced rotor is informed of the oscillatory movement around its longitudinal axis. Due to the imbalance with a certain angular coordinate, the rotor begins to make angular oscillations relative to the horizontal axis passing through a point located on the axis. The amplitude of these oscillations is proportional under certain conditions to the magnitude of the imbalance, and the orientation of the horizontal axis of the resulting angular oscillations indicates its location.

The disadvantage of this method is the inability to determine the dynamic imbalance.

The technical result of the proposed method is to expand the scope due to the possibility of balancing rotors with more than one plane of reduction of imbalance.

This is achieved by the fact that oscillatory movements about its axis are reported to the vertically mounted rotor, and unbalance parameters are defined as a function of rotor vibrations about the horizontal axis. In this case, initially one of the reduction planes is combined with the horizontal axis, relative to which oscillations occur, arising from the action of the tangential components of unbalanced inertia forces. This arrangement of the rotor will exclude the influence of the imbalance of this plane on the measurement result of this stage. After determining and eliminating the imbalance in this plane, the rotor is moved in the axial direction at a fixed distance and the measurements are repeated.

In addition, a balanced rotor in the mode of angular oscillations is simultaneously informed of a uniform rotation around its own axis by an angle of not more than φ _max = 181 ° until the maximum value of the amplitude of oscillations relative to the horizontal axis arising from unbalanced inertial forces.

Figure 1 shows the initial position of the rotor, and figure 2 shows the position in the second measurement stage; figure 3 is a top view of the rotor (and imbalance) in the process of balancing.

The method is implemented as follows: on the lower base 1, an oscillating drive 2 and a rotor 3 are installed (see figures 1, 2). The lower base 1 is connected to the upper base 4 uprights 5, which allow the lower base to move along with the rotor in the axial direction. The upper base 4 is connected to the bed with the help of two torsion bars 6, on which the system makes forced oscillations caused by inertia due to rotor imbalance.

The rotor 3 together with the base 1 and the drive 2 is installed with the possibility of moving it along the axis by the value of h and fixing it in two positions, in the first of which one of the reduction planes, for example the lower one, passes through the center of the torsion bars 6, and in the second one it is offset (see Fig. 2). Sensors 7 and 8 measure the phase and amplitude of the forced oscillations from the action of inertia forces from rotor imbalance.

The process of balancing a rotor with two reduction planes begins with measuring the imbalance in the upper plane. In this case, the lower plane is combined with the axis of the torsion bars (see Fig. 1). Then the drive is started and the rotor begins to perform torsional vibrations relative to its own axis, while gradually turning. In the presence of imbalance in the upper plane of reduction, a dynamic moment acts on the rotor, causing the entire system to rotate relative to the OX axis. Moreover, the moment, and, accordingly, the oscillations will be maximum in the case when the angle φ = 0 (see figure 3). The measurement of the imbalance produced by the sensor 8 mounted on the upper base relative to the stationary reference system. The reference signal sensor 7 mounted on the rotor is designed to receive a signal about the position of the rotor at each moment of time in order to determine the location of imbalance (quadrant).

After determining the imbalance in the upper plane of reduction, it is necessary to eliminate it in order to exclude the influence of this imbalance on subsequent measurements. Otherwise, it must be taken into account in further measurements.

After eliminating (or measuring) the imbalance in the upper plane of reduction, the rotor together with the lower base and the drive are moved up by h (the value of h is selected, taking into account the design parameters of the balanced rotor, for example, the value of h can be taken equal to 1/2 ... 1/4 of the distance between the reduction planes) and make repeated measurements (see figure 2).

Thus, the use of the proposed method allows you to measure the parameters of the unbalance of the rotor with high accuracy in two planes to bring the imbalance. The method is convenient in operation and does not require large material costs for its implementation.

Information sources

1. M.E. Levit, V. M. Ryzhenkov, Balancing of parts and assemblies. - M., Engineering, 1986

2. US patent No. 5359885, CL 73/146, 1994

3. USSR author's certificate No. 1497496, cl. G01M 1/16, 1989

4. Copyright certificate of the USSR No. 712708, cl. G01M 1/16, 1980

Claims (2)

1. The method of dynamic balancing of rotors, namely, that the vertically mounted rotor is informed of oscillatory movements about its axis, and the imbalance parameters are determined as a function of the rotor vibrations relative to the horizontal axis, characterized in that the rotor is balanced in the following sequence: initially, one of the reduction planes combine with the horizontal axis, relative to which oscillations occur, arising from the action of the tangential components of unbalanced forces inertia, and measure these oscillations; after determining and eliminating the imbalance in the first plane, the rotor is axially displaced by a fixed distance and the oscillation measurements are repeated. 2. The method according to claim 1, characterized in that the installed vertically unbalanced rotor in the mode of angular vibrations, at the same time report a uniform rotation around its own axis by an angle of not more than φ _max = 181 ° until the maximum value of the amplitude of the oscillations relative to the horizontal axis arising from unbalanced inertia forces.

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