RU2579754C1 - Inductor synchronous generator - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention can be used in production of inductor synchronous generators. Objective is achieved by reducing value of bearing currents. Inductor synchronous generator consists of housing, stator pack, toothed rotor packet bearing shields, bearings, labyrinths mating parts of labyrinths, shaft, key slot on shaft. Labyrinths, pressing outer races, and in their mating parts fitted on shaft is carried out at three or more flat ribs and projections, identical in shape and size. Ribs of labyrinths are with clearance in space between projections of their mating parts, and projections of latter between ribs of labyrinths.

EFFECT: higher reliability, durability and manufacturability of generators.

4 cl, 5 dwg

Description

The invention relates to electric machines and can be used in the manufacture of synchronous inductor-type generators intended for power supply of passenger and refrigerator cars and other consumers of electric energy, as well as in the manufacture of other types of electric machines.

The aim of the invention is to increase the reliability, durability and manufacturability of synchronous inductor generators, mainly opposite-pole [1] (hereinafter referred to as generators), and to improve their characteristics.

It is known that bearing currents in electric machines (hereinafter - EM) lead to damage to the raceways of bearings, which in turn leads to a rapid failure of these EM. Moreover, for synchronous inductor generators, the problem of bearing currents is more acute than for other types of electric machines [2], due to the fact that the pronounced tooth shape of the rotor with, as a rule, asymmetric distribution of the excitation fluxes and rotor eccentricity leads to the appearance of high-frequency components of EMF, voltage and current, which are wired from by the use of bearings with an insulating coating is ineffective, since the capacitive resistance of a current-insulating coating is pnikov inversely proportional to the frequency of the voltage is small, and accordingly, the quantity of high frequency current passing through the bearing, quite noticeable.

Therefore, to more effectively limit the bearing currents, another technical solution adopted in this application for the prototype is used, namely, electric shunting of the bearing by creating a parallel electrical circuit passing through the shield, bearing caps and then through the sliding contact in the form of a conductive lubricant filled into grooves data covers [3], or the installation of conductive elements from copper wire in these grooves [4]. The disadvantage of these technical solutions is the fact that the above-mentioned sliding contacts, shunting the bearing, have some transient ohmic resistance, which during operation of the generator will gradually increase due to the inevitable appearance of an oxide film, mainly during EM downtime, which will lead to a decrease in current through parallel electrical circuit and, accordingly, an increase in current through the bearing.

Moreover, the conductive grease will gradually leak out of the grooves and also dry out, and the conductive elements will wear out, which will also lead to an increase in the resistance of the sliding contact, a decrease in the effect of shunting and, accordingly, an increase in the current through the bearing.

To eliminate the mentioned drawbacks, the authors proposed the construction of a synchronous inductor generator (Fig. 1), consisting of a package of stator 1, frame 2, bearing shields 3, bearings 4 and 5 with a current-insulating coating of their outer cages, labyrinths 7, with at least three flat ribs 6 and the outer race of bearings 4 and 5, which are pressing on the inner end faces, of the counterparts of the labyrinths 8, having at least three flat protrusions 10 of the same shape and size as the ribs 6, the shaft 9, the rotor package 16. The labyrinths 7 are electrically isol are insulated from bearings 4 and 5 by a current-insulating coating of the outer casing of the latter.

The ribs 6 of the labyrinths 7 during assembly of the generator are led into the space between the protrusions 10 of the counterparts of the labyrinths 8 and, accordingly, the said protrusions 10 are brought into the space between the ribs 6 without touching each other, providing a technologically and structurally acceptable air gap between all surfaces of the labyrinths 7 and their response parts 8.

The protrusions 10 and ribs 6 form essentially a flat capacitor in which they are its plates, while the capacitance of this capacitor is determined by formulas known in electrical engineering and depends on a number of factors, including the total area of the ribs 6 and protrusions 10, on the size of the air gaps between them and from other factors. Thus, the said capacitors, the lining of which are the ribs 6 of the labyrinths 7 and the protrusions 10 of their counterparts 8, shunt the bearings 4 and 5 from the high-frequency components of the current spectrum flowing through their components due to the low capacitance of these capacitors due to the increased area of the plates consisting of at least three ribs 6 and three protrusions 10, and a high frequency shunt current. As for the low-frequency components of the bearing currents, the protection against their flow through the bearings is carried out in a known manner, namely the use of a current-insulating coating of their outer casing.

On the other end of the bearings 4 and 5, their fixation is carried out in the usual known manner, namely, by pressing their outer cages with a clamping ring 11 by means of bolts 12 through the cover 13 and by pressing the inner casing with an oil ring 14 using a nut 15 screwed onto the shaft 9. In this case, the package the rotor 16 with all rotating parts, including the shaft 9 and the counterpart of the labyrinth 8, is electrically separated from the fixed part of the generator, including the stator 1, housing 2, shields 3 and labyrinths 7, air gaps and a current-insulating coating of external m bearings 4 and 5. To simplify the reading of figure 1 the structural elements identical numbering is given mainly to only one of the bearing assembly.

Thus, the proposed design allows to protect the bearings 4 and 5 from high-frequency components of the current spectrum by shunting the bearings with labyrinths 7 and their counterparts 8, each having at least three ribs 6 and protrusions 10, which form an essentially flat capacitor, respectively, which are essentially flat arising in the stator package and the generator housing, which will prevent damage to the raceways of the bearings and, thus, increase the reliability and durability of the EM.

Generators are known [2, 5], adopted as prototypes, in which a cylindrical stator package made of electrical steel is pressed with a constant diameter along a diameter into a steel or cast-iron case, which also has an internal diameter constant along the length.

The disadvantage of this articulation of the stator package with the housing is its insufficient rigidity, due to the fact that during the pressing process the front of the stator package, which consists of sheets of solid silicon electrical steel, partially cuts and deforms the softer metal of the housing, mainly its front part, and after full mounting, the second half of the stator is weakened relative to the corresponding mating subjected to deformation of the front of the housing.

Therefore, retention of the stator package from angular and linear movements, as well as from vibrations during operation of the generator, does not occur along its entire length, but only about half, which reduces the stator-housing connection stiffness and, as a result, the reliability and durability of the product , and also increases the noise and vibration of the generator.

Another disadvantage of the mentioned known designs of articulation of the stator package with the housing is their low-tech, due to the fact that in the process of pressing the stator package into the housing, high-precision equipment is required to ensure alignment of their axes in coordinate and angle.

To achieve this goal, namely, to increase the reliability, durability and manufacturability of the generator, the authors proposed a stepwise design for articulation of the stator package with the generator case (Fig. 2), in which the mating cylindrical surfaces of the stator package and housing 2 are made of two different diameters in length - large D ₁ and less than D ₂ . Moreover, the difference between these diameters is insignificant and amounts to 1.5-2.5 mm, and the length of each part of the stator with its diameter D ₁ or D ₂ is half its length.

The proposed technical solution allows to significantly increase the stiffness of the joint of the stator package with the housing, since in the process of pressing it in, the front part of diameter D ₂ freely passes inside the cylindrical surface of the front part of the housing of diameter D ₁ , keeping its inner bore diameter unchanged and then rigidly articulated with the second part of the housing with a diameter of D ₂ , and, accordingly, the second part of the stator package with a diameter of D _{1 is} rigidly articulated with the front of the housing of the same diameter, which ultimately provides a strong articulation of these nodes along the entire length of the stator and leads to increased reliability and durability of the generator.

At the same time, the proposed design (Fig. 2) increases the manufacturability of pressing the stator package into the case due to the fact that the front part of the case with a diameter of D ₁ is essentially a trap and centering of the stator package having a diameter in its front entry part by 1.5-2, 5 mm smaller than the aforementioned diameter D ₁ , and thus ensures its grip and alignment during pressing into the housing without the use of high-precision equipment.

Thus, the proposed technical solution increases the reliability, durability and manufacturability of the generator.

Generators are known in which, to improve the shape of the EMF curve of the stator, a bevel of the rotor tooth from 1/2 to 2/3 of the pole division is used [1], the tooth shape is chosen different, including rectangular, trapezoidal, comb, but with a constant height [6, 7], and its width at the periphery of the rotor is set within 0.35-0.41 tooth division of the rotor [6. 7].

The disadvantages of these technical solutions adopted for the prototypes are:

- low-tech assembly of the rotor, caused by the difficulty of fitting its package on the shaft key, which has a significant bevel of teeth up to 2/3 of the pole division, and mechanical resistance during this landing, caused by both the mentioned significant bevel, and the inevitable expansion of electrical steel sheets in long keyway of the rotor package;

- a noticeable decrease in the EMF of the stator, caused by a large bevel to 2/3 of the pole division [6, 7], which worsens the main parameter of the generator, namely its electromotive force;

- the presence of a large spectrum of higher harmonics of the EMF of the armature [1, 6], leading to high losses in steel and, accordingly, increased heating of the generator and a decrease in its efficiency.

To reduce these shortcomings, namely, to improve manufacturability and improve the characteristics of generators, and thus achieve the set goal, a rotor design is proposed (Fig. 3a, 3c, 3c), in which the keyway is made on the shaft at an angle to the axis of the shaft, creating a bevel teeth, two times smaller than that of the prototype, namely, in the range from 1/4 to 1/3 of the pole division; in the sheets of the rotor an angular shift is provided within 1 ° 10′-1 ° 20 ′ between the axes of the keyway and the tooth, and the rotor package is assembled from two identical half-packets; in this case, the first half-pack is put on the key face side, and the second back side (Fig. 3a, 3c), which, taking into account the shift between the axes of the key and the tooth, will provide an angle between the axes of the teeth of two half-packs equal to 2 ° 20′-2 ° 40 ′, that is, double with respect to said angular shift between the axes of the key and the tooth; the upper peripheral part of the tooth is 0.37-0.42 tooth division wide and forms part of a circle made by a radius providing a variable working air gap from the value of "δ" along the axis of the tooth to "1.25δ" at its edges.

This technical solution allows you to:

- to improve the manufacturability of the assembly of the rotor package with the shaft in comparison with the prototypes by halving the bevel angles of the keys on the shaft and corresponding keyways on the rotor half-packages, as well as by using instead of one full package of two half-packages, each of which being in two times shorter than the full package, it will have much less mechanical resistance when mounting them on a shaft with a key, providing greater convenience and ease of assembly with respect to prototypes;

- improve the characteristics of the generator by increasing its EMF with respect to the prototypes due to the use of half the bevel angle of the rotor teeth in comparison with the prototypes - from 1/4 to 1/3 of the pole division; at the same time, it is possible, to the same extent as that of the prototypes, to improve the shape of the EMF due to the angle shift of two half-packets in the manner described above;

- reduce the magnitude of the higher harmonics of the EMF of the armature through the use of a rotor, providing a variable working air gap above the tooth from a value of "δ" to "1.25δ". A slightly increased air gap at the edges of the tooth will reduce the amplitude of the higher harmonics of the EMF, and a slightly increased tooth width relative to the prototypes, equal to 0.37-0.42 tooth division, will compensate for the small decrease in the EMF caused by the increase in the equivalent air gap. A decrease in the magnitude of the higher harmonics of the EMF leads to a decrease in the high-frequency components of the current and, as a result, a decrease in heating and an increase in the efficiency of the generator, i.e., an improvement in its characteristics.

Bibliography

1. Alper N.Ya., Terzyan A.A. Inductive generators. M., Energy, 1970, S. 14-17, C. 59, S. 45-50.

2. Zhezherin R.P. Inductive generators. M.-L., Gosenergoizdat, 1961, S. 285-286, S. 281, Fig. 8-12.

3. Copyright certificate SU 1224909, cl. Н02К 5/16. Bearing assembly of an electric machine. 1984, bull. No 14 on 04/15/1986

4. Copyright certificate SU 1451808, cl. Н02К 5/16. Bearing assembly of an electric machine. 1987, bull. No.2 of January 15, 1989

5. Fedyakov Yu.V., Pakhomov D.M., Popov S.V., Frolov M.E., Semenov O.S. A series of synchronous generators of the EGV type for the life support systems of passenger cars. Electrical Engineering, 2011, No. 2, P. 38.

6. Balagurov V.A. Design of special AC electric machines. M., Higher School, 1982, S. 225, Fig. 6.23, S. 223 (6.38), S. 225, S. 212-214

7. Balls B.C. Electric machine inductor generators. M.-L., Gosenergosdat, 1961, S. 50, Fig. 2-5, S. 49 (2-7), S. 51.

Claims (4)

1. Inductor synchronous generator, consisting of a housing, a stator package, a gear package of the rotor, bearing shields, bearings, labyrinths, mates of the labyrinths, shaft, keyway on the shaft, characterized in that in the labyrinths that compress the outer bearings of the bearings, and in them mating parts mounted on the shaft, respectively, are made of three or more flat ribs and protrusions, identical in shape and size, with the edges of the labyrinths with a gap in the space between the protrusions of their counterparts, and the protrusions of the last between do ribs of labyrinths. 2. Induction synchronous generator according to claim 1, characterized in that the articulated cylindrical surfaces of the stator package and the housing are stepwise in length and are made in two different diameters, differing by 1.5-2.5 mm; the length of each of these parts differing in diameter is half the length of the rotor. 3. Induction synchronous generator according to claim 1, characterized in that the keyway on the shaft is made at an angle to the axis of the shaft, creating a bevel of the teeth of the rotor package within 1 / 4-1 / 3 of the tooth division, and the rotor package consists of two identical half-packets , in each of which an angular shift of 1 ° 10′-1 ° 20 ′ is provided between the axis of the keyway and the axis of the tooth, with the first half-package being put on the key face and the second back side, creating an angular shift between the axes of the teeth of the half-packages equal to 2 ° 20′-2 ° 40 ′. 4. The inductor synchronous generator according to claim 1, characterized in that the outer peripheral surface of each tooth of the rotor forms a part of a circle with a radius providing a variable working air gap from the value “δ” along the axis of the tooth to “1.25δ” at its edges and is made wide 0.37-0.42 tooth division.

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