RU2579830C1 - Method of determining static disbalance of rotor on balancing stools - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building, specifically to methods of determining static disbalance of rotor on balancing blades, and can be used for static balancing of different rotors. Disclosed method of determining static disbalance of rotor on balancing blades, wherein rotor imbalance is changed relative to contact zone of rotor bearing surfaces of blades and parameter which characterises value of imbalance driving rotor to motion, then rotor is remounted on blades to another angular position and repeated change imbalance and measurement of parameter, measured parameter represents inclination of balancing blades of initial horizontal position change of imbalance are synchronous rotation of blades relative to axis aligned with rotor axis, and measurement of inclination angle of blades is performed at beginning of movement of rotor.

EFFECT: technical result is to reduce complexity and duration due to transition from mass selection operations unbalanced loads, rotor turning at a certain angle, measurement of four angles of inclination of blades of rotor during reinstallation.

1 cl, 7 dwg

Description

The invention relates to mechanical engineering, and in particular to methods for determining the static imbalance of the rotor on the balancing knives and can be used for static balancing of various rotors.

A known method for determining the static imbalance of the rotor on the balancing knives, in which a change is made in the imbalance of the rotor relative to the contact zone of the rotor with the supporting surfaces of the knives and a parameter characterizing the amount of imbalance causing the rotor to move is measured, then the rotor on the knives is reset to a different angular position and the imbalance is repeated and parameter measurement. In this case, as the measured parameter in the first measurement, an unbalance angle is used, by which the rotor rotates under the action of gravity from the initial to a stable position. When re-measuring, the mass of the corrective weight selected for balancing the rotor after reinstalling the rotor by turning 90 ° from a stable equilibrium position is used as the measured parameter.

(see Levit M.E., Ryzhenkov V.M. “Balancing of parts and assemblies.” - M.: Mashinostroenie, 1986, p. 62: “Machines for the static balancing of SBS-4.” Method for determining the static imbalance, see ibid., p. 50, Fig. 2.1.c).

The disadvantage of this method is the relatively low accuracy, which does not allow to determine the static imbalances of rotors that are not balanced enough, but are in a state of indifferent equilibrium at any angular position of the rotor due to the action of friction forces in the bearings.

More accurate is the method for determining the rotor static imbalance on balancing knives, in which the rotor imbalance is changed relative to the contact zone of the rotor with the supporting surfaces of the knives and a parameter characterizing the imbalance that causes the rotor to move is measured, then the rotor on the knives is reset to a different angular position and repeated unbalance change and parameter measurement. In this case, the masses of corrective weights selected for rotation of the rotor under the influence of gravity by 45 ° after reinstalling the rotor in eight angular positions are used as the measured parameters.

(see Levit M.E., Ryzhenkov V.M. “Balancing of parts and assemblies.” - M.: Mashinostroenie, 1986, p. 51, “Circular bypass method”).

This method, which is the closest analogue to the proposed technical solution, allows you to determine the static imbalances of rotors in a state of indifferent equilibrium at any angular position of the rotor.

The disadvantage of the closest analogue is the relatively high complexity and duration of its implementation, associated with the need for a large number of operations to select eight unbalanced masses that rotate the rotor by 45 °.

The technical result of the claimed method is to reduce the duration and complexity of the measurements of the static imbalance of the rotors.

The specified technical result is ensured by the fact that in the method for determining the static imbalance of the rotor on the balancing knives, in which the change in the imbalance of the rotor relative to the contact zone of the rotor with the supporting surfaces of the knives is made and a parameter characterizing the amount of imbalance causing the rotor to move is measured, then the rotor on the knives is reset in another angular position and repeat the change in the imbalance and the measurement of the parameter, it is new that the angle of incidence is used as the measured parameter the bosom of balancing knives from the initial horizontal position, the imbalance is changed by synchronous rotation of the knives relative to the axis coinciding with the axis of the rotor, and the measurement of the angle of inclination of the knives is performed at the moment the rotor begins to move.

The essence of the claimed invention is illustrated by graphic materials on which:

- in FIG. 1 shows the initial position of the rotor on the balancing knives;

- in FIG. 2 shows the position of the rotor at the boundary of the equilibrium state when the knives are tilted in the clockwise direction relative to the axis coinciding with the axis of the rotor, in the drawing coinciding with the point O;

- in FIG. 3 shows the position of the rotor at the equilibrium state when tilting the knives in a counterclockwise direction;

- in FIG. 4 shows the construction in the XOY coordinate system of the line on which the rotor's center of mass is located;

- in FIG. 5 shows, in a 90 ° XOY coordinate system, plotting the line on which the rotor's center of mass is located;

- in FIG. 6 shows the location of the center of mass of the rotor as the point of intersection of the constructed lines in FIG. 4 and FIG. 5;

- in FIG. 7 shows the geometric justification for finding the center of mass of the rotor on the constructed lines.

The claimed method is implemented as follows.

In the initial position, the rotor 1 (Fig. 1) is in a state of indifferent equilibrium on the knives 3. Moreover, the center of mass M (x _m , y _m ) of the rotor for any angular position of the rotor on horizontal knives is inside circle 2 with a radius r equal to the coefficient friction of rolling the rotor over the knives. The contact zone of the rotor with the knives is indicated by 4. Track 5 of the gravity vector mg is within the friction zone, limited by a radius r on both sides of the contact zone 4.

The imbalance of the rotor 1 relative to the contact zone 4 of the rotor 1 with the supporting surfaces of the knives 3 is changed by slow synchronous rotation of the knives in the clockwise direction relative to the axis O coinciding with the axis of the rotor. At the beginning of rolling, when trace 5 of the gravity vector extends beyond the friction zone (Fig. 2), the angle of inclination of the knives is measured.

Similarly, the angle of inclination β of the knives is measured after the rotor unbalance is changed by rotating the knives counterclockwise, as shown in FIG. 3.

The line on which the center of mass of the rotor is located is defined as the line coinciding with the median AD of triangle ABC, the sides AB and AC of which are angles α and β, respectively, with the vertical axis OY, as shown in FIG. four.

To build another line on which the rotor center of mass is located, the rotor on the blades is reinstalled to a different angular position, preferably by rotating the rotor 90 ° for reasons of simplicity of the calculation algorithm, for example, as shown in FIG. 5, while the axis OX is directed downward from the drawing. The imbalance change is repeated by tilting the knives clockwise and counterclockwise until the moment the rotor begins to move and the corresponding angles γ and δ are measured. The line on which the rotor center of mass is located is defined as the line coinciding with the median ЕН of the triangle EFG, the sides of which EF and EG make up with the axis ОX, respectively, the angles α and β, as shown in FIG. 5.

The center of mass of the rotor in the XOY coordinate system is defined as the intersection point of the constructed lines coinciding with the medians AD and EH, as shown in FIG. 6.

A geometric confirmation of the location of the center of mass of the rotor on the constructed lines coinciding with the corresponding medians is shown in FIG. 7. At the boundary points of the friction zone and the point M (x _m , y _m ) of the center of mass, the triangle MLN is constructed, the median MA is drawn in it. The triangle MLN, rotated through 180 °, will occupy the position of the triangle APQ with the median AM coinciding with MA. The triangle ABC is similar to the triangle APQ and coincides with similar sides. Obviously, their medians also lie on one straight line, on which the point M (x _m , y _m ) of the center of mass of the rotor is located. It is proved similarly that the center of mass lies on a line coinciding with the median ЕН.

To obtain the formulas for the analytical calculation of imbalance, we denote:

OD = d;

OH = h.

The equations of the lines coinciding with the medians are of the form:

Solving these equations together, we find the coordinates of the center of mass:

where the values of d and h are calculated by the formulas:

d = (tgβ-tgα) R / 2;

h = (tgδ-tgγ) R / 2.

The value of static imbalance is calculated by the formula:

where m is the mass of the rotor.

The imbalance angle is calculated by the formula:

ψ = arctan (y _m / x _m ).

Thus, the proposed technical solution allows to determine the static imbalance of the rotor on the balancing knives, bypassing a large number of time-consuming and lengthy operations of selecting eight unbalanced masses that rotate the rotor by 45 ° in eight angular positions of the rotor on the knives. In the proposed method for determining the static imbalance of the rotor on the balancing knives, it is sufficient to measure the four angles of inclination of the knives and perform one reinstallation of the rotor.

Claims (1)

A method for determining the rotor static imbalance on balancing knives, in which the rotor imbalance is changed relative to the contact zone of the rotor with the supporting surfaces of the knives and a parameter characterizing the amount of imbalance causing the rotor to move is measured, then the rotor on the knives is reset to another angular position and the imbalance is changed again and parameter measurement, characterized in that as the measured parameter using the angle of inclination of the balancing knives from the original horizontal position, the imbalance is changed by synchronous rotation of the knives relative to the axis coinciding with the axis of the rotor, and the measurement of the angle of inclination of the knives is performed at the moment the rotor begins to move.

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