AT515989A2 - Short circuit rotor - Google Patents

Abstract

A short-circuit rotor (1) has a rotor core (2) in which beveled or axially parallel grooves (4) into which copper rods (3) are inserted are provided. To the copper rods (3) stray segment webs (5) are formed, which protrude to the outer surface (7) of the rotor core (2). The copper rods (3) are insulated from the inner surfaces (9) of the grooves (4) and supported on these over axially parallel ribs (8). The ends of the copper rods (3) projecting beyond the lateral end faces (12) of the rotor core (2) and having notches (11) are electrically conductively connected on both sides of the rotor core (2) with cast aluminum short-circuiting rings (20). In individual grooves (4) of the material of the aluminum shorting rings (20) existing and with the short circuit rings (20) integrally formed rods (15) are provided. The aluminum rods (15) are arranged at equal angular intervals, in particular 90 °, from each other.

Description

The invention relates to a short-circuit rotor (squirrel cage rotor) having the features of the introductory part of claim 1.

Short circuit rotors (cage rotors), as used for asynchronous machines, have shorting rings. The problem with both known rotors is that it is difficult to save material, and this problem is also not solved by using aluminum short-circuiters that can be produced by the die-casting process.

A short-circuit rotor is known from DE 102 47 484 A1. In this rotor for an inverter-fed asynchronous machine, the electric conductors of the rotor formed as copper rods are embedded in grooves of the laminated rotor (squirrel cage). Electrically insulating layers are provided between the copper bars and the laminated core of the rotor. About the design of the short-circuit ring of the known short-circuit rotor DE 102 47 484 Al gives no information. The cross-sectional shape of the grooves in the laminated core, in which the copper rods are accommodated, may according to DE 102 47 484 Al be rectangular, trapezoidal or drop-shaped.

JP H09-65625A shows a short-circuit rotor in which electrical conductors are provided in the form of copper bars. In addition, in the known short-circuit rotor, further bars are provided which are formed together with the end rings by casting from aluminum or an aluminum alloy.

JP H09-65625 A shows a short-circuit rotor in which electrical conductors in the form of rods of different materials (aluminum and copper) are provided.

A similar short-circuit rotor is known from CN 201956853 U.

The invention has for its object to provide a short-circuit rotor, which is easy to manufacture. Furthermore, the should

Energy efficiency in asynchronous machines by the use of short-circuit rotor according to the invention improved (increased).

This object is achieved according to the invention with a short-circuit rotor having the features of claim 1.

Preferred and advantageous embodiments of the invention are the subject matter of the subclaims.

In the case of the short-circuit rotor according to the invention, both short-circuit rings made of aluminum, ie the short-circuit ring on the AS side (output side) and the short circuit ring on the BS side (brake side), can be produced in one operation, for example by an aluminum die-casting method.

If n-slots (for example n = 24) are provided in the rotor core of the short-circuit rotor according to the invention, copper rods can be omitted from m slots (for example m = 4). These m-grooves, which are evenly distributed, in particular, over the circumference of the rotor core (equal angular intervals (eg, 90 ° mechanical degrees) from each other, permit the flow of liquid aluminum from one end (AS) of the rotor core to the other end (BS) (eg, from the driven side) AS " to the brake side " BS "), so that both short rings are made in one operation, ie to which ends of the copper rods projecting beyond the end faces of the rotor package can be cast.

With the short-circuit rotor according to the invention, smaller slip values can be achieved in practice and thus also reduced loss values. The result of this measure is that the efficiency of the motor (asynchronous machine) is significantly increased with the same construction volume. In addition, in the motor according to the invention, parasitic effects such as " cross currents " in the rotor cage, kept small.

Further details and features of the invention will become apparent from the following description of a preferred embodiment with reference to the drawings.

It shows:

1 shows schematically a detail of a short-circuit rotor according to the invention,

Fig. 2 in an oblique view (partially) a Kurzschlussrotor invention and

Fig. 3 shows schematically a double-notched copper rod.

In the short-circuit rotor 1 according to the invention, a row of copper rods 3 as electrical conductors are uniformly distributed over the outer circumference of the rotor core 2 (laminated core). The copper rods 3 are arranged in axially parallel or beveled grooves 4 in the rotor core 2, the main body of the rotor 1. In the exemplary embodiment shown, the grooves 4 and the copper rods 3 have mutually corresponding, in the example substantially teardrop-shaped, cross-sectional shapes. Other cross-sectional shapes for the grooves 4 and the copper rods 3, such as polygonal (triangular, quadrangular) or circular are also contemplated.

Integrally formed with each of the copper rods 3 is a dispersion segment 5 (" scattering groove ") projecting into the open end of the groove 4 in the rotor core 2. The outer end surface 6 of the strip segment 5 is in alignment with the (cylindrical) outer surface 7 of the rotor core 2.

For safe guidance of the copper rods 3 in the grooves 4 of the rotor assembly 2, three longitudinal ribs 8 are provided on the copper rods 3, which abut against the inner surface 9 of the grooves 4 and thus serve as a guide for the copper rods 3 (" 3 point " Instead of the ribs 8, on the outer surface of the copper rods 3, e.g. conical or frusto-conical projections which bear against the inner surface 9 of the grooves 4 may be provided.

In order to insulate the copper rods 3 from the rotor core 2, either insulating materials may be inserted or, preferably, electrical insulation is provided by oxide layers on the inner surface 9 of the grooves 4 and / or the outside of the copper rods 3.

In a preferred embodiment, the isolation by oxide layers can be made as follows.

First, the rotor core 2 is thermally treated (blueing), so that on this an oxide layer, in particular on the inside 9 of the grooves 4, is achieved.

The insulation of the blued rotor core 2 is reinforced by impregnating the rotor core 2 in a resin bath which gives a impregnating insulation 10.

The copper rods 3, which are to be inserted into the slanted or paraxial grooves 4 of the rotor core 2, are independent of the two aforementioned measures before

Processing (insertion of the copper rods 3 in the grooves 4) also oxidized, so that on the copper rods 3 a reliable electrical insulation is realized.

It should also be pointed out that the copper rods 3 inserted into the grooves 4 of the rotor package 2 have, for example, a drop shape. Regardless of the shape of the copper rods 3 and the corresponding shape of the grooves 4, the following measures can be implemented according to the invention:

The scattering grit 5 can be realized by a special shaping of the copper rods 3, as can be seen in particular and by way of example from FIG.

The longitudinal ribs 8 (or protrusions) on copper rods 3 provide an advantageous " 3 point " lead so that by the above-described measures (blushing and impregnation in the resin bath) it is possible to insert the rods 3 into the rotor core 2 contact copper bar rotor core package only at three points or lines. This results in a favorable reduction of parasitic cross currents. Between the guide projections (which may be continuous ribs 8 or single or knob-like (cone-shaped) projections) there is a well-defined insulating layer 10 of cast resin material through the impregnating resin insulation.

2, the short-circuit rings 20 are made of aluminum in the short-circuit rotor 1 according to the invention. It is provided that the ends of the copper rods 3 projecting over the rotor core 2 on both sides engage in the short-circuiting rings 20, for example, a teardrop-shaped cross-sectional shape.

As shown in Fig. 3, the copper bars 3 of the shorting rotor 1 of the present invention have notches 11 at either end or both ends (Fig. 3). The shape of the notches 11 is not essential. Curved notches 11 are contemplated as well as angled shapes, e.g. triangular or trapezoidal notches 11.

In the short-circuit rotor 1 according to the invention, the short-circuiting rings 20 are made of aluminum and are manufactured, for example, by the aluminum die-casting method. Thus, the ends of the copper rods 3 projecting beyond the end faces 12 of the rotor core 2 are cast in aluminum in one operation in order to form the short-circuit rings 20. Normally, there is no gap 21 between the rotor core 2 and the cast aluminum idler ring 20 on the AS side and the BS side.

If in the present " aluminum " not only (technically) pure aluminum, but also aluminum alloys are meant. -

In this case, copper rods 3 are arranged in the grooves 4 of the rotor assembly 2 (laminated core) such that ends of copper rods 3 having notches 11 and not having notches 11 project beyond the rotor package 2 at both ends (on the output side "AS" and brake side "BS").

The arrangement of the copper bars 3 is the following:

At the rotor circumference, in the grooves 4 of the rotor core 2 are alternately " doubly notched " and a " not slotted " copper bar 3 sandwiched.

Before the aluminum short-circuit bars 20 are cast, the overhanging ends of the copper bars 3 can be made mechanically and / or chemically bare in order to achieve a good electrically conductive connection between the copper bars 3 and the short-circuiting rings 20.

In the short-circuit rotor 1 according to the invention, copper rods 3 are not used in all grooves 4 of the rotor core 2 with preferably notched and not-notched ends projecting beyond both end faces 12 of the rotor core.

In at least one groove 4 of the rotor core 2 no copper rod 3 is used. For example, with twenty-four (24) grooves 4 of the rotor package 2, four (4) grooves 4 spaced apart from each other by 90 ° are free of copper rods 3 and become prone to casting the short-circuit rings 20 filled with aluminum, so that in these grooves 4 of the rotor core 2 aluminum rods 15 are provided, which are integral with two short-circuit rings 20. This makes it possible to manufacture the short-circuiting rings 20 (both) by one operation in the aluminum die-casting process from one side, for example, the driven side, in manufacturing the short-shot rotor 1 of the invention.

Advantageously, it can be provided in the context of the invention in a possible embodiment that the short-circuit rings 20 from the end faces 12 of the rotor stack 2 distance (gap 21), so that an advantageous decoupling is achieved. Due to the decoupling of the shorts 20 molded onto the copper bars 3 from the rotor core 2, there are advantages with respect to the cooling of the shorting ring 20. This applies both to the operation of a motor equipped with the inventive short-circuit rotor 1 by air turbulence on the one hand, and to the manufacture of the short-circuit rotor 1 according to the invention when the copper rods 3 are encapsulated with the short-circuiting rings 20 in the aluminum die-casting process, on the other hand.

In summary, an embodiment of the invention can be described as follows:

A short-circuit rotor 1 has a rotor core 2, in which slanted or axially parallel grooves 4 into which copper rods 3 are inserted are provided. To the copper rods 3 are spline segments 5 are formed, which protrude to the outer surface 7 of the rotor assembly 2. The copper rods 3 are insulated from the inner surfaces 9 of the grooves 4 and supported on these überachsparallele ribs 8. The protruding ends of the copper rods 3, which have notches 11, over the lateral end faces 12 of the rotor core 2 are electrically connected on both sides of the rotor core 2 with molded aluminum short-circuiting rings 20. In individual grooves 4 are made of the material aluminum of the short-circuiting rings 20 existing and integrally formed with the short-circuiting rings 20 rods 15. The aluminum rods 15 are arranged at equal angular intervals, in particular 90 °, from each other.

Claims (16)

Claims 1. A short-circuit rotor (1) for an asynchronous machine comprising a rotor core (2) having outwardly open flutes (4) towards the outermost surface (7), in which inclined or parallelled grooves (4) comprise electrical conductors in the form of copper rods (3 and shorting rings (20) are provided at both ends of the shorting rotor (1), wherein in at least one groove (4) there is provided a rod (15) made of aluminum like the shorting rings (20), and at ends of Copper bars (3) notches (11) are provided, which notches (11) are filled with the material aluminum of the shorting rings (20), characterized in that the copper bars (3) protrude beyond the side surfaces (12) of the rotor core (2), over the rotor core (2) have projecting ends of copper rods (3) alternately notches (11) and are free of notches (11), and that in the grooves (4) alternately copper rods (3) having at both ends notches (11), un D copper rods (3), which are formed by notches (11) are freely inserted. 2. short-circuit rotor according to claim 1, characterized in that the rod (15) made of aluminum with one, preferably both of the short-circuiting rings (20) is integrally formed. 3. short-circuit rotor according to claim 1 or 2, characterized in that two or more than two, in particular four, bars (15) are provided made of aluminum. A short-circuit rotor according to claim 3, characterized in that the aluminum bars (15) are equally angularly spaced relative to the axis of the rotor package (2). 5. Short-circuit rotor according to one of claims 1 to 4, characterized in that the at least one rod (15) made of aluminum and the short-circuit rings (20) are cast in one piece, in particular cast in the die-casting process. 6. short-circuit rotor according to one of claims 1 to 5, characterized in that in the rotor core (2) twenty-four grooves (4) are provided and in four grooves (4) bars (15) which consist of aluminum, are provided. A rotor according to any one of claims 1 to 6, characterized in that the ends of the copper bars (3) are encapsulated with the material aluminum of the short-circuiting rings (20) via the side surfaces (12) of the rotor assembly (2). 8. Rotor according to one of claims 1 to 7, characterized in that notches (11) with respect to the axis of the rotor assembly (2) facing radially inward and / or radially outward. Rotor according to one of claims 1 to 8, characterized in that the copper rods (3) have a teardrop-shaped cross-sectional shape. A rotor according to any one of claims 1 to 9, characterized in that stray segment webs (5) are provided on the copper bars (3) and on the at least one aluminum bar (15) in the open end of the grooves (4). A rotor according to claim 10, characterized in that the outer surfaces (6) of the spreading segment webs (5) are flush with the outer surface (7) of the rotor core (2). Rotor according to claim 10 or 11, characterized in that the stray segment webs (5) protrude into the shorting rings (20). A rotor according to any one of claims 1 to 12, characterized in that the outer surfaces of the copper rods (3) and / or the inner surfaces (9) of the grooves (4) are provided with an insulating layer, the insulating layer being in particular an oxide layer. A rotor according to any one of claims 1 to 13, characterized in that the ends of the copper bars (3) are made mechanically and / or chemically bare prior to the casting of the shorting rings (20). A rotor according to any one of claims 1 to 14, characterized in that the shorting rings (20) are molded by the die casting process. A rotor according to claim 15, characterized in that the shorting rings (20) are cast in a single process step.