DE102006021419A1 - Electric motor e.g. asynchronous motor, has bypass-retainer with rods exhibiting electrical joints at front and rear end areas, where rods connected with each other are combinable into groups and are arranged in circumferential direction - Google Patents

Abstract

The motor has a bypass-retainer with rods (1-24) exhibiting electrical joints at axially front and rear end areas. Samples of electrical connections exhibit discrete rotation symmetry around a rotor axis between two joints, where the durability of the samples is smaller than the rate of the rods. The durability of the samples corresponds to the number of poles e.g. rotor and/or the stator, where each pole is woundable. The rods that are connected with each other are combinable into groups, where the rods are successively arranged in a circumferential direction.

Description

The The invention relates to an electric motor, in particular comprising at least an inductively excitable winding in the secondary part, preferably a runner cage.

at Asynchronous motors are known as short-circuit cages that come with the rotor the electric motor are connected. It is known, the cage so build up that an axial front ring and an axially rear Ring with rods are connected.

The Winding the stator is very complex and is also called three-phase winding designated.

From the US 6,359,355 B1 a simple stator winding for an electric motor is known, which is executable with Einzelzahnbewicklung. However, this winding can not be used with such secondary parts, whose excitation is caused by induction, because caused by a single tooth winding Oberfelder lead to unwanted excitation fields with negative effects on noise and vibration.

Of the The invention is therefore based on the object, an electric motor cost and easy to educate.

According to the invention Task in the electric motor according to the features specified in claim 1 solved.

Important features of the invention in the electric motor are that the electric motor is designed with a rotor comprising a short-circuit cage
wherein the short-circuiting cage comprises bars which have electrical connection points at least at their axially front and rear end regions
wherein the pattern of all electrical connections between each two connection points have a discrete rotational symmetry about the rotor axis, whose count is smaller than the number of rods.

there the electric motor comprises at least one excitable by induction Winding in the secondary part, preferably a rotor cage, the here also as a short-circuit cage is designated.

The Compounds are exemplary on a ring as exemplified on a thick-walled axially shorter as a radially extended hollow cylinder, realized by in one such corresponding circumferentially consecutive interruptions are provided. Alternatively, the compounds by means of various Rings providable. But instead of rings are also different geometrically shaped Parts usable for this purpose. In particular, the bars are too can be arranged on a single diameter and the connections with crossovers.

From The advantage here is that Einzelzahnbewicklung is usable, ie every single pole can be wound. The technique of wrapping is So now applicable to asynchronous machines, while still a quiet uniform rotation is reachable. Other advantages of this winding are also that one inexpensive Production possible is because the wrapping of the teeth easier and faster executable is as an otherwise required retraction of the wires in grooves. Furthermore is a high efficiency achievable, since the winding head is very short accomplished is. About that In addition, a compact design can be achieved because the winding over very short executable is. Also, a simple isolation is foreseeable, since the phase separation eliminated. It is also advantageous that the spectrum of generated magnetic rotating field waves is very homogeneous. So basically there is this spectrum only a main one Polyphase wave. Further waves with different pole pairs and direction of rotation have a vanishing amplitude.

Consequently leads the Excitement of the runner from the stator fields to mainly a runner field and therefore to a smooth running of the asynchronous motor, although single tooth winding accomplished has been.

essential The advantage, therefore, is that the expression of a discrete symmetry the one in the short-circuit cage occurring current loops from the many possible generated by the stator Rotary field waves are screened out the one that the desired Pole number of the rotor corresponds.

at an advantageous embodiment corresponds to the count the number of poles, in particular the rotor and / or the stator corresponds. The advantage here is that the number of poles in a simple manner, namely by a symmetry of the connections and connection points realized is. Not the number of bars inside the electric machine is crucial but this Symmetry of the pattern of connections and junctions.

at an advantageous embodiment, at least two connection points not connected. The advantage here is that not all bars with all rods are connected. Thus, connections can be saved and thus additionally the engine improvable.

In an advantageous embodiment, the connected rods are each grouped into groups, which are arranged one after the other in the circumferential direction. The advantage here is that the Her position is simple and inexpensive executable and the respective groups are manufacturable as individual components and attachable to the rotor shaft or a carrier connected to this.

at In an advantageous embodiment, the connected rods are each grouped into groups arranged circumferentially enforcing are. The advantage here is that a high efficiency achievable is, in particular a high torque with low losses. In particular are also very high-pole arrangements executable with such advantages.

at an advantageous embodiment, the connection points arranged in a circle. The advantage here is that the connections easy to implement, in particular by means of rings or rings with circumferential interruptions.

at an advantageous embodiment, the connection points two or more circles, wherein the compounds, in particular the assigned to the connection points or to the connection points connected, also arranged only within these circles are, in particular not between circles of different diameters. The advantage here is that no crossovers or overlaps the connections are necessary with each other.

at an advantageous embodiment, the circle or circles in a first axial region and / or at a first axial Job provided. The advantage here is that one or more Rings are usable for the preparation of the compounds without or are executed intermittently, and thus a simple and inexpensive way to connect usable is despite the sophisticated invention Template.

at In an advantageous embodiment, not all bars are connected to each other electrically connected. The advantage here is that a number and thus also pole number can be produced, which is lower than the number of the bars.

at an advantageous embodiment, the number of poles of the rotor 2, 4, 6 or 8. It is advantageous that even such low and medium numbers of poles are easily accessible.

at According to an advantageous embodiment, the stator and / or his Stator laminated core individually wound teeth. It is advantageous that the stator so simple, fast and inexpensive to produce is. Because the production of individually wound poles of the stator is with high quality executable, especially in comparison to the complicated feeding of a or multi-phase three-phase winding in the stator lamination stack, because In this case, the winding wires are directed differently forces get abandoned.

at an advantageous embodiment, the number of poles of the rotor and the number of teeth of the Stators no common prime factor, with at least one the numbers have at least two prime factors. Is an advantage thereby that Polrasten, Nutrasten as well as the losses are reducible.

at According to an advantageous embodiment, the motor is an asynchronous motor or comprises at least one electrical machine part according to the asynchronous motor principle works. The advantage here is that too Generators are executable according to the invention or also engines whose rotor partial permanent magnets to form a Partial motor according to the synchronous principle or material recesses for Forming a partial motor according to the reluctance principle comprises.

at an advantageous embodiment, the engine is an internal rotor or an external rotor. Especially the motor is designed as a rotary or linear motor. From The advantage here is that the invention in many different ways of engines that have at least one electric sub-machine after the asynchronous motor works includes.

Further Advantages emerge from the subclaims.

Under Motor is always an electric machine in the invention understood, including generator or the like.

1, 2, ... 24

Rod

100

wave

120

electrical connection

121

none electrical connection

The invention will now be explained in more detail with reference to figures:
The electric motor is provided as an asynchronous motor in an internal rotor design. The rotor rotates with the short-circuit cage inside the stator. The associated stator laminated core is designed with inwardly directed teeth, the teeth are individually wound.

In the 1a a first variant according to the invention of the short-circuit cage of the rotor is schematized drawn in unwound representation. The rotor shaft 100 is also indicated schematically to illustrate the viewing direction.

This includes the cage 24 axially aligned rods arranged in 4 modules and electrically connected together. This means that the six bars of the first module, so the bars with the numbers 1 to 6 , are electrically connected to each other.

The another three modules are also made of six each electrically connected rods executed. The modules are not electrically connected to each other.

Of the axially front and rear ring is in the invention of each four ring segments assembled. You could get the front and the back Ring also as a ring with four interruptions.

at a further embodiment of the invention the sticks go not parallel to the axial direction but with a helix angle. Thus, even less restlessness can be generated than during the rotational movement.

In a further embodiment of the invention, the electrical connection 120 preferably carried out by means of welded connection. Alternatively, the connection is made cohesively and / or already provided during manufacture. Each module can be produced by die casting or other casting method, so that the module can be produced in one piece in each case. Suitable materials include metals such as aluminum or copper, as well as alloys comprising at least portions of such metals.

Instead of at one as an internal rotor engine running the invention also includes a correspondingly executed variant as an external rotor.

In a further embodiment of the invention, as in 1b shown, in contrast to 1a omitted a certain number of rods from the modules. In this variant too, the essential rotating field carries out the main excitation of the rotor short-circuit cage. From the large number of magnetic stator rotating fields of the single-pole winding, only the desired rotating field causes excitation of the rotor with cage. This makes it possible to combine the simple and cost-effective production of the stator winding by single-tooth winding with a cage also simple and inexpensive to produce runners.

This is achieved by providing the two axially front and rear Shorting rings are interrupted in a suitable manner. To this Way you can in the rotor winding form preferred poles.

In the simple embodiment according to 1a or 1b For example, the poles are formed by forming a number of rod groups corresponding to the pole pair number of the stator, which are electrically connected to each other. In the case of the embodiment 1b In addition, individual bars in the middle of the pole are not formed, which also reduces the moment of inertia.

Like in the 2a shown schematically as a developed front view, three arranged in floors rotor cages are formed, which are connected to different bars. In this case, the first interrupted ring is arranged on a smaller, the second on the middle and the third on a larger diameter. The first ring connects the bars 1 and 4 , He also connects the bars 7 and 10 , The other connection points are in the 2a marked dark. The wave is also indicated to indicate the viewing direction.

Thus, two bars each of the first module, which are the bars 1 to 6 includes, electrically connected.

Like in the 2 B shown schematically, other connection systems are advantageously used and also stimulate only the corresponding desired four-pole fundamental wave.

Here are the first, second and third ring as in 2a concentrically arranged, but executed without interruption. The electrical connections 120 are marked dark. By way of example, the first ring connects the bars 1 . 2 . 7 . 8th . 13 . 14 . 19 and 20 , The non-connections 121 are marked lighter. In these areas, therefore, there are only overlaps without electrical contact or substantial electrical contact.

at a further embodiment of the invention no rings but types of connection technology are chosen.

The in the 1a . 1b . 2a . 2 B Compounds shown in the circumferential direction have such a pattern that repeats the connection pattern after every 90 °. In other words, a rotation of 90 ° converts the short-circuit cage into itself.

It will be according to 1a and 1b So the bars divided into groups whose number corresponds to the number of poles. Thus there are four groups. The groups follow each other in the circumferential direction.

Both 1a . 1b . 2a . 2 B the number of poles 4 is realized.

To 2a and 2 B the rings are circumferentially offset from one another. In the latter arrangement, a rotation of 360 ° / 24 converts the first ring into the second and likewise the second into the third ring.

The important feature of the invention is therefore in any case that the Pattern of joints between rod and ring respectively the quantity of rings is a symmetry corresponding to the number of poles having. In the figures, the number of poles is four and the symmetry thus fourfold. If the number of poles on the rotor short-circuit cage is different, the symmetry is appropriate different.

Consequently As it were, the symmetry of the shorting cage squares the corresponding one Rotary field wave of the plurality of the stator with Einzelpolbewicklung generated rotating field waves, which corresponds to the symmetry of the symmetry.

Claims (15)

Electric motor with rotor, comprising a short-circuit cage, wherein the short-circuit cage comprises rods, which have at least at their axial front and rear end portions electrical connection points, characterized in that the pattern of all electrical connections between each two connection points discrete rotational symmetry around the rotor axis whose number is less than the number of rods. Electric motor according to at least one of the preceding Claims, characterized in that the number of poles, in particular of the rotor and / or the stator. Electric motor according to at least one of the preceding Claims, characterized in that at least two connection points are not connected. Electric motor according to at least one of the preceding Claims, characterized in that the connected rods can each be combined into groups are arranged in succession in the circumferential direction. Electric motor according to at least one of the preceding Claims, characterized in that the connected rods can each be combined into groups are, which are arranged passing through in the circumferential direction. Electric motor according to at least one of the preceding Claims, characterized in that the connection points on a circle are arranged. Electric motor according to at least one of the preceding Claims, characterized in that the connection points to two or more circles are arranged, the compounds, in particular those assigned to the joints or to the joints connected, also arranged only within these circles are, in particular not between circles of different diameters. Electric motor according to at least one of the preceding Claims, characterized in that the circle or circles in one first axial region and / or provided at a first axial location are. Electric motor according to at least one of the preceding Claims, characterized in that not all rods are electrically connected to each other are. Electric motor according to at least one of the preceding Claims, characterized in that the number of poles of the rotor 2, 4, 6 or 8 is. Electric motor according to at least one of the preceding Claims, characterized in that the stator and / or its stator lamination stack individually wound teeth includes. Electric motor according to at least one of the preceding Claims, characterized in that the number of poles of the rotor and the Number of teeth of the stator has no common prime factor, wherein at least one of the numbers has at least two prime factors. Electric motor according to at least one of the preceding Claims, characterized in that the motor is an asynchronous motor or at least one electrical machine part comprises, according to the asynchronous motor principle is working. Electric motor according to at least one of the preceding Claims, characterized in that the engine is an internal rotor or an external rotor is. Electric motor according to at least one of the preceding Claims, characterized in that the motor is a rotary or a Linear motor is.