Laminated armature core for an electric motor

In an armature packet (1) for an electric motor, having a plurality of armature laminations (2, 3), in each of which a plurality of winding slots (4) for receiving an armature winding (5) are embodied, and the winding slots (4) of adjacent armature laminations (2, 3) are located in alignment with one another and form a conduit (6), a better positional fixation of the armature winding (5) is attained by providing that the winding slots (4), associated with one conduit (6), of different armature laminations (2, 3) have different geometries. The same is attained by providing that at least some of the winding slots (4) each have an influx conduit (11), each of which discharges into its region oriented toward the center of the armature packet (1).

BACKGROUND OF THE INVENTION

The invention is based on an armature packet for an electric motor.

For producing armature packets for electric motors, individual armature laminations are stamped in such a way that recesses for armature windings are stamped into the lamination in the same operation. The armature windings are wound into these winding slots and fixed in their position by impregnation with a suitable material. In principle, there are two known methods for this.

In dip roller-burnishing, the wound armature packet is sealed by being dipped and rolled in the impregnating material (such as polyester resin). Next, the impregnating material is hardened, so that the winding together with the armature packet forms a rigid structure. In the drip process, a variant of dip roller-burnishing, the armature packet is received, rotating, in a suitable device and the impregnating material is dripped onto it. Next, the impregnating material is hardened as in dip roller-burnishing. However, in dip roller-burnishing and the drip process, the problem is that the impregnating material does not always penetrate all the voids between the armature windings. To assure that these voids will be completely filled, all the process parameters, such as temperature, viscosity, winding density of the wires, and venting, must be optimally adapted to one another and adhered to as exactly as possible. Otherwise, uneven filling of the winding slots with impregnating material and air inclusions, which thus leads to the formation of bubbles. As a result, the windings are fixed only inadequately in their position against the centrifugal forces that occur in operation and against vibration. As a consequence, short-circuited coils occur along with vibration from radial shifting of the armature winding and hence of the center of mass, resulting in a shorter service life of the motor.

In armoring, for additional fixation, so-called cross bandages of paper or plastic cords are used. These bandages on the one hand provide a certain protection of the windings from abrasive grinding powders and on the other provide an additional positional fixation of the windings in the packet. As a result, while the defects of impregnation are essentially compensated for, nevertheless this method is very complicated and thus expensive in the production process, and so it is employed only for high-quality motors.

SUMMARY OF THE INVENTION

An armature packet for an electric motor according to the invention has the advantage over the prior art that by means of the winding slots of different armature laminations, which winding slots are associated with one conduit and have different geometries from one another, the armature windings are better fixed in their position. As a result, there are also fewer short-circuited coils, which are otherwise caused by friction among loose winding wires. Likewise, a lessening of vibration is attained, since the armature winding, after the impregnating material has hardened, can no longer shift radially even at high rpm and hence strong centrifugal forces, so that no change in the center of mass occurs. The same is also true of an armature packet for an electric motor according to the invention as defined by the characteristics of claim4, since because of the influx conduits, the impregnating material reaches even the lower windings well.

Because the geometry of every other winding slot of one conduit has a larger cross section than the winding slot of the adjacent armature lamination, the impregnating material can penetrate deep, down to the bottom of the winding slot, so that by capillary action it reaches the innermost winding wires and fixes them against any kind of motion once it has hardened. Besides the possibility of providing every other winding slot with a larger cross section, it is equally possible to provide any other sequence in the conduit.

Because the geometry of every other winding slot has a larger cross section than the adjacent winding slots of the same armature lamination, armature laminations that are made with the same stamping tool are produced by rotation relative to one another, each about an adjacent winding slot, to form a regular pattern of winding slots of small cross section and winding slots of large cross section over the entire armature packet. Besides the possibility of providing every other winding slot with a larger cross section, it is equally possible to provide any other sequence.

Because the influx conduit of all the winding slots associated with one conduit communicate with one another through at least one transverse conduit, oriented substantially parallel to the central longitudinal axis of the armature packet, the impregnating material reaches all the influx conduits very well and thus reaches the winding wires located very deep in the individual winding slots. Besides the typical case of one transverse conduit, it is equally possible to provide an arbitrary number of transverse conduits. The geometry of the transverse conduit may be round, oval, rectangular, or arbitrarily shaped.

Because the transverse conduit is located between the winding slot and the central longitudinal axis of the armature packet, the magnetic flux is affected least, since the transverse conduit is located quite close to the center of the armature packet.

Because the influx conduits are each embodied as at least one stamping in the respective armature lamination, which include the transverse conduit, very simple, economical production is provided for the individual armature laminations, which are then joined together to form the armature packet. Besides the normal case of one stamping, two or more stampings are also possible. This is particularly true in the case of an oval or rectangular transverse conduit.

Because the sequence of one purely transverse conduit, one influx conduit leading away to the right from the transverse conduit, and one influx conduit leading away to the left from the transverse conduit in a given conduit is repeated again and again, there is a simple, secure way of feeding the impregnating material to the winding wires located deep at the bottom in the winding slots. Moreover, it is also possible to provide influx conduits that extend vertically upward. The sequence of the influx conduits and of the transverse conduit can have any arbitrary order.

Because the cross section of each winding slot has a constriction on the outer end, in particular with two undercuts, good introduction of the winding wires located in the winding slots and protection of them against mechanical wear from outside are assured.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

InFIGS. 1 through 3, a first exemplary embodiment of an armature packet1of the invention is shown. InFIG. 1, the armature packet1is shown without its armature winding5(seeFIG. 2). The same is also true forFIG. 3. The armature packet1has a plurality of armature laminations2,3, lined up with one another along a central longitudinal axis17. The armature laminations2,3have winding slots4along their circumference. In the case shown, there are a total of twelve winding slots4, which are each located equidistant from one another. The winding slots4are embodied such that on the circumference of the respective armature lamination2,3they have a constriction15, which widens via two undercuts16into a larger cross section. The twelve winding slots4are merely an example; any other number of winding slots4may also be embodied in the armature laminations2,3. The winding slots4need not be equidistant from one another, either.

The winding slots4of the individual armature laminations2,3in line with one another are oriented such that in each case one conduit6oriented toward the central longitudinal axis17is formed. The armature winding5(seeFIG. 2) is drawn into this conduit6.

The winding slots4of two adjacent armature laminations2,3are designed differently in terms of their cross section. The first armature lamination2shown inFIG. 1has winding slots4of smaller cross section than the second armature lamination3.

InFIG. 2, a section through a second armature lamination3is shown, perpendicular to the central longitudinal axis17. It is readily seen here that the cross section of the winding slot4of the second armature lamination3is larger than that of the armature lamination2, which in this view protrudes past the outline of the winding slot4of the second armature lamination3. Thus for the winding slot4of the second armature lamination3, there is both a wider constriction15′ and undercuts16that extend farther into the armature lamination3. Moreover, the entire winding slot4of the second armature lamination3is wider and deeper than the winding slot4of the first armature lamination2.

The armature winding5has been introduced into the conduit6in a known manner in an insulation paper18. It is limited in its circumference by the winding slot4, having the smaller cross section, of the first armature lamination2. As a result, there is a void, completely surrounding the armature winding5, in the winding slot4of the second armature lamination3. Upon the impregnation of the armature packet1with an impregnating material by the known methods, the impregnating material can penetrate deeply, down to the bottom of the winding slot4of the second armature laminations3. By capillary action, the impregnating material thus reaches as far as the innermost winding wires and fixes them, after hardening, against any kind of motion. This means that the winding wires in the winding slots4can no longer move, and thus no short-circuited coils occur. Moreover, no vibration from radial shifting of the armature winding5occurs, and hence also no shifting of the center of mass. This means that the service life of the motor in which the armature packet1is built in is lengthened, compared to the armature packets known from the prior art.

InFIG. 3, a side view of the armature packet1described above is shown, which is located on an armature shaft19. The surface pattern of the armature packet1here can be seen, resulting from the various constrictions15in the individual armature laminations2,3. For greater clarity, the armature windings5are not shown. The narrow constrictions15of the first armature lamination2extend as far as the narrow solid lines, which extend continuously, parallel to the central longitudinal axis17.

InFIG. 4, a different surface pattern is shown, resulting from a different combination of armature laminations2,3,3′ in the form of a second exemplary embodiment. The first armature laminations2and the second armature laminations3are designed identically to those of the first exemplary embodiment (FIGS. 1 through 3). However, third armature laminations3′ are also included. These have an enlarged cross section only for every other winding slot4. The remaining winding slots of the third armature lamination3′ have the same size as the winding slots4of the first armature lamination2.

The order of the armature laminations2,3,3′ is such that in alternation, a second armature lamination3and then a third armature lamination3′ are located between two first armature laminations2. The result, always in the same sequence, is different-sized constrictions15,15′,15″, specifically successively a narrow constriction15, a wide constriction15′, a narrow constriction15, and a medium-wide constriction15″. After that, the entire sequence is repeated.

Once again, the same advantages are attained by the voids that act as capillaries, so that complete fixation of the winding wires is attained.

InFIG. 5, a third exemplary embodiment of the invention is shown. In this exemplary embodiment, unlike the two exemplary embodiments described above, the slot4is embodied identically in all the armature laminations7, in the manner known from the prior art. First, however, it must be remembered that in addition to the characteristics described below, an embodiment of the winding slots4in accordance with one of the two exemplary embodiments described above (shown inFIGS. 1 through 4) is entirely possible.

An armature winding5is introduced into the winding slot4, in an insulation paper18. A vertical part21of an influx conduit11is stamped into the armature lamination7from the surface of the armature lamination7. In the further armature lamination behind it (concealed by the armature lamination7shown), conversely, a horizontal part20of the influx conduit11is stamped. The horizontal part20of the influx conduit11discharges into the winding slot4on its lower end, oriented toward the center point of the armature packet1. This alternating arrangement of armature laminations7with a vertical part21and a horizontal part20is repeated over the entire length of the armature packet1. However, it is equally possible to replace some of the armature laminations7with a vertical part21or horizontal part20with an armature lamination (not shown) that has only a bore in the region where the vertical part21meets the horizontal part20. As a result of the arrangement shown inFIG. 5, in the region where the vertical part21intersects the horizontal part20of the influx conduit11, a continuous bore in the direction of the central longitudinal axis17(not shown) is created. As a result, in the impregnation, it is possible for the impregnating material to reach well into the lower region of the armature winding5.

In dip roller-burnishing, the embodiment shown has the effect that the impregnating material is well fed by the additional influx conduits11to the winding wires located deep at the bottom.

InFIGS. 6 and 6a-c,a fourth exemplary embodiment is shown, which is similar in construction to the third exemplary embodiment shown inFIG. 5. Once again, the armature laminations8,9,10located in line with one another are designed such that their winding slots4all have the same cross section. However, once again it is true that in addition to the characteristics described below, an embodiment in accordance with one of the first two exemplary embodiments, shown inFIGS. 1 through 4, can also be made.

In contrast to the third exemplary embodiment, the influx conduit11, which in the third exemplary embodiment has an opening in the surface of the armature lamination7, is replaced in the form of a transverse conduit12, which extends essentially parallel to the central longitudinal axis17(not shown). In the front armature lamination8shown inFIG. 6a,only the transverse conduit12is present below the winding slot4. The middle armature lamination9located behind it has an oblique stamped out recess13on the right, which communicates with the lower end of the winding slot4. The rear armature lamination10, adjoining the middle armature lamination9, has a left stamped out recess14, embodied mirror-symmetrically to the right stamped out recess13. The left stamped out recess14also communicates with the lower part of the winding slot4. When the three armature laminations8,9,10ofFIGS. 6a-care located one behind the other, the result in the region of the transverse conduit12is a continuous conduit that extends over the entire length of the armature packet1. The arrangement of the three armature laminations8,9,10shown is repeated periodically. As a result, after each three armature laminations8,9,10, the same order occurs again. It should be remembered, however, that any other sequence of the three armature laminations8,9,10is also possible. It need not repeat periodically once; the user is free to select the lineup behind one another in whatever way is most favorable for that user's application.

By means of such an embodiment, the same advantages are attained in dip roller-burnishing as is the case with the third exemplary embodiment shown inFIG. 5. Here as well, the impregnating material passes through the transverse conduit12and the right stamped-out recesses13and left stamped-out recesses14communicating with it to reach the lower part of the winding slots4and thus the deep winding wires. Moreover, an embodiment in accordance with the fourth exemplary embodiment also has the decisive advantage in the drip process that improved venting takes place, and hence the formation of bubbles is greatly reduced. Moreover, such a subject has the advantage that the transverse conduit12, the right stamped out recess13and the left stamped out recess14are located quite close to the center of the armature lamination and thus affect the magnetic flux only slightly.

InFIG. 7, a fifth exemplary embodiment is shown, which is constructed similarly to the fourth exemplary embodiment shown inFIGS. 6 and 6a-c.Once again, the armature laminations7in line with one another are designed such that their winding slots4all have the same cross section. However, here as well it is true that in addition to the characteristics described below, an embodiment in accordance with one of the first two exemplary embodiments, which are shown inFIGS. 1 through 4, can be made.

In contrast to the fourth exemplary embodiment, the transverse conduit12is not circular but instead is embodied as an oval stamped out recess23. The armature packet1in the fifth exemplary embodiment has armature laminations7which have L-shaped stampings24that begin at the winding slot4. The L-shaped stampings24have both a vertical part22and a horizontal part25. The two vertical parts22are joined to the winding slot4at the sides of the lower region of the winding slot. The two horizontal parts25are oriented toward one another. As a result, a web26remains between the two L-shaped stampings24. This web26is embodied as slenderer in the region of the horizontal parts25than in the region of the vertical parts22.

In the armature lamination that is concealed behind the armature lamination7shown, an oval stamping23, shown in dashed lines, which has no communication with the winding slot4is embodied. The oval stamping23is located such that it concludes at least partly in alignment with the horizontal parts25of the L-shaped stamping24. As a result, two transverse conduits12oriented parallel with the central longitudinal axis (not shown) of the armature packet1are embodied.

The possibility exists of locating the two embodiments of the armature lamination7, as described above, in alternating order. Moreover, the two types of armature laminations7may also be arranged in an arbitrary order with repetitions of the one type of armature laminations7and the other type. It is furthermore equally possible to install armature laminations8,9,10of the fourth exemplary embodiment shown inFIGS. 6a-cin the armature packet1. It must merely be assured that a continuous transverse conduit12through all the armature laminations7,8,9,10is created. This transverse conduit12need not necessarily extend parallel to the central longitudinal axis17of the armature packet1.

In summary, it can be said that an improved positional fixation of the armature winding5in the winding slots4is attained by all five exemplary embodiments of the invention. Mixing the characteristics shown in the five exemplary embodiments described can be done without problems. By combining the various types of armature laminations of the five exemplary embodiments shown—both with an influx conduit11and transverse conduit12or without these additional means—a virtually unlimited variety of armature packets1can be obtained. As a result, very individualized adaptation to the requirements in the production process of the particular armature packet1is achieved. This quite infinite variety of design options has all the advantages recited above.