RU2426014C1 - Calculated-simulation procedure for shaft balancing - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used at assembly and balancing sectional rotors with magnetic suspension of compressors of gas-compressor units (GCU). Magnetic cores are mounted on the shaft. There are measured values of their maximal radial run out relative to balancing surface and their angles relative to a control point of the shaft. The cores are taken off. The shaft is divided into sections. There are chosen planes of cross sections of weights passing through their centres as planes of correction. There are determined correcting weights of sections of the shaft and corrected unbalances of sections of the shaft by removing material in planes of correction. Simulation loads are set in places of material removal. Also, angles of places of simulation loads installation relative to the control point of the shaft are determined from dependence:

while correcting weights (weights of the imitation loads ) from dependence:

where: m_c is correcting weight, m_s is weight of a simulation load, M_i is weight of the shaft section, D is diameter of the shaft section in the place of load installation, X, Y are coordinates of weights of sections; also, the simulation loads are removed upon completion of assembly and rotor balancing.

EFFECT: reduced unbalance of rotor caused with concentricity of its assembly, upgraded accuracy of balancing.

Description

The invention relates to mechanical engineering and can be used in the assembly and balancing of prefabricated rotors with a magnetic suspension of compressors of gas pumping units (GPU).

A known method of balancing prefabricated rotors described in GOST ISO 11342-95, in which select the plane of correction of imbalances and balance the shaft by the method of balancing a rigid rotor.

This method is taken as a prototype.

The disadvantage of this method is that after installing the shaft in the rotor in the compressor housing, its rotation is carried out with some eccentricity relative to the axis along which the balancing was carried out. The eccentricity is due to the error in processing surfaces that determine the axis of rotation of the rotor during operation.

The magnitude of the imbalance of the rotor caused by the eccentricity of its installation, can reach values exceeding the permissible level of imbalance by orders of magnitude.

So, for example, a rotor weighing 500 kg after balancing has an imbalance not exceeding 150 g · mm in each correction plane. After installation with an eccentricity of 8 μm, which is the permissible error of the surface treatment of the magnetic cores, the imbalance in each correction plane will be 2000 g · mm, which is 13 times greater than the allowable imbalance.

The technical task of the present invention is to reduce the imbalance of the rotor shaft, due to the eccentricity of its installation, providing improved balancing accuracy.

The technical result is achieved by the fact that in the method in which the unbalance correction planes are selected and the shaft is balanced according to the method of balancing the hard rotor, magnetic cores are installed on the shaft, their maximum radial runout is measured relative to the balancing surfaces and their angles relative to the shaft reference point, the cores are removed, the shaft is divided into sections, choose the plane of the cross sections passing through their centers of mass, as the correction planes determine the corrective mass stkov shaft is corrected imbalances removing shaft material sections in planes correction simulation set weights in the field of material removal, wherein the angles of installation locations of simulated weights relative to the control point of the shaft is determined from the relationship

and corrective masses (masses of simulation weights) from the dependence

where m _k is the correcting mass, m _and is the mass of the simulation weight, M _i is the mass of the shaft section, D is the diameter of the shaft section at the place of installation of the weight, X, Y are the coordinates of the center of mass of the section, while the simulation weights are removed after assembly and balancing rotor.

Removing the weights after balancing allows you to bring the axis of the balanced shaft mass closer to its axis of rotation in the compressor.

The method is illustrated by drawings, presented in figures 1, 2, 3.

Figure 1 explains the measurement of the maximum runout of the surfaces of the magnetic bearings.

Figure 2 explains the definition of the correction planes and the correction of imbalances.

Figure 3 explains the determination of the coordinates of the centers of mass of the sections.

In the drawings indicated:

1 - rotor shaft;

2, 3 - magnetic cores;

4 - simulation weights on the rotor shaft;

a ₁ , ..., a _i - plane correction of the shaft;

A, B - balancing surfaces of the shaft;

B, G - working surfaces of the rotor;

E - places of removal of metal in the planes of the shaft correction.

The method is as follows.

The rotor shaft 1 (Fig. 1) with magnetic cores 2, 3 mounted on it is mounted on measuring prisms by surfaces A, B. Relative to these surfaces, the maximum runout of surfaces B, D of magnetic cores is measured, and the angles of these maximum radial beats are relative to the control shaft points. The eccentricities of the centers of mass of the magnetic cores are determined from the dependence

and the coordinates of the centers of mass from the dependence

;

;

,

,

where _Δ D _i is the maximum radial runout of the magnetic core, α _i is the angle of the maximum radial runout of the magnetic core.

Break the shaft into sections, determine the mass of the sections (M _i ) and the position of the centers of mass of the sections, for example, using CAD.

The planes of the cross section of the sections that pass through the centers of mass of the sections are selected as the imbalance correction planes.

The coordinates of the centers of mass of the plots are determined

where z _a1 , ..., z _ai is the distance from the end face of the rotor to the corresponding section.

Determine the corrective masses and masses of simulation weights from the dependence

The angles of the places of material removal of the shaft sections and the installation of simulation weights relative to the control point of the shaft are determined from the dependence

The imbalances of the plots are corrected, while the metal is removed in places E. Install imitation weights 4 at the places of metal removal.

Balance the shaft according to the technology provided for rigid shafts.

At the end of the assembly and balancing of the rotor, all simulation weights are removed, which eliminates the imbalance of the shaft in the rotor during the transition from balancing to working surfaces.

Thus, the application of the proposed method many times reduces the imbalance of the rotor due to the eccentricity of its installation, which increases the accuracy of the balancing.

Claims (1)

The calculation and simulation method of balancing the shaft, in which imbalance correction planes are selected, balancing the shaft according to the method of balancing a hard rotor, characterized in that magnetic cores are mounted on the shaft, measure their maximum radial runout relative to the balancing surfaces and their angles relative to the shaft reference point, take off the cores, the shaft are divided into sections, choose the plane of the cross sections passing through their centers of mass, as the correction planes, determine the correction iruyuschie weight shaft portions, shaft portions imbalances corrected by removing material in the correction planes is set in field simulation weights removing material, wherein the angles of installation locations of simulated weights relative to the control point of the shaft is determined from the relationship:

and corrective masses (masses of simulation weights) from the dependence:

where m _k is the correction weight, m _and is the mass of the simulation weight, M _i is the mass of the shaft section, D is the diameter of the shaft section at the place of installation of the weight, X, Y are the coordinates of the centers of mass of the sections, while the simulation weights are removed after assembly and balancing rotor.

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