DE102011108042A1 - Stator manufacturing method for electric machine e.g. electrical generator, involves assembling set of single tap segments to stator ring, and potting casting material in such manner that stator carrier is formed - Google Patents

Abstract

The method involves assembling a set of single tap segments (2) to a stator ring (4), where the tap segments are braced with one another by using a biasing device that is designed as a divided disk hub or a slit lever hub. A casting material i.e. plastic, is potted in such a manner that a stator carrier (3) is formed. The tap segments are enclosed at an outer perimeter, so that the tap segments are braced with one another and held in a stator ring mold. An independent claim is also included for a stator for an electric machine.

Description

The invention relates to a method for producing a stator for an electric machine according to the features of the preamble of claim 1 and a stator for an electric machine according to the features of the preamble of claim 7.

From the prior art, as in the EP 2 256 901 A2 described, a potted electric motor known in which the yoke and the individual teeth of the stator are potted with plastic.

The invention is based on the object to provide an improved stator for an electric machine and an improved method for its production.

The object is achieved by a method for producing a stator for an electrical machine having the features of claim 1 and a stator for an electric machine having the features of claim 7.

Advantageous embodiments of the invention are the subject of the dependent claims.

In a method for producing a stator for an electric machine, for example an electric motor and / or an electric generator, according to the invention a plurality of individual tooth segments are assembled to form a stator ring, clamped together and encapsulated with a potting compound at least in regions such that a stator carrier is formed.

The stator surrounds the single tooth segments on an outer periphery so that they are clamped together and held in Statorringform. The method enables a simple and cost-effective production of the stator carrier due to permissible higher tolerances of the single tooth segments, since these do not have to be pressed into an already finished stator carrier made of metal, as usual in the prior art. Ie. Single tooth segments with a lower production quality can also be used. Since these do not have to be pressed into the stator, but are first assembled into a stator and then shed, occur in the finished stator significantly lower joining tolerances of the single tooth segments.

In addition, the use of potting compound, such as plastic, a cost savings and weight reduction compared to stator made of metal is achieved. Furthermore, the use of potting compound allows a low Vergusstemperatur, whereby the single tooth segments are not damaged, and also an isolation of the single tooth segments is achieved by the potting compound.

Another advantage of the potting compound, in particular of a plastic, is a noise-damping effect, wherein vibrations are attenuated by the stator in a stator of potting compound and forwarded less from the stator to a housing to the outside.

A selection of a material for casting the stator can in particular also take place according to acoustic properties of the material, so that in addition to the property of the fatigue strength and torque transmission of the stator and a property of comfort formation is added during operation.

When casting the single tooth segments to a stator, in which the stator is formed from the potting compound, in particular, the single-tooth segments can be mitvergossen with the single-tooth windings. For this purpose, a mold not only include the single tooth segments, but also partially cover the single-tooth windings, which are then encapsulated by the potting compound.

For this purpose, the potting compound has an electrically insulating property, so that the single-tooth windings do not have to be previously isolated and / or potted in a separate working step.

In an advantageous development, a contacting device, in particular a switching ring, can be encapsulated by the potting compound when casting the single tooth segments.

A contacting device allows contacting of all single tooth windings of a stator, which is in particular usually designed as switching rings in the form of copper tracks.

For example, has a contacting device in a three-phase electric machine via three switching rings, one switching ring per phase, which are arranged on the stator. The single-tooth windings are contacted with the switching rings and are thus connected via the circumferential switching rings in the form of annular copper tracks, all at the same time with a high-voltage connection.

In an alternative Verschaltungsart, the contacting device may in particular have a further switching ring as a neutral point.

When casting the stator together with the contacting device in particular the individual copper tracks of the switching rings are inserted into a casting mold of the stator for pouring, so that the potting compound connects the copper tracks to the stator during casting and at the same time also isolates the shift rings from one another. For this purpose, an alignment of the copper tracks in the mold is necessary because the copper tracks must not touch to avoid electrical contact and between the switching rings sufficient space for filling with potting compound must be present.

But it is also possible to shed a partially prefabricated contacting device with the stator, in which the individual copper tracks are previously placed in a separate housing, which holds the copper tracks of the shift rings together and isolated from each other.

The partially prefabricated contacting device can be inserted together with the housing in a mold of the stator, in which case no independent alignment of the individual copper tracks is more necessary because they are already isolated in a previous manufacturing step, the insertion of the copper tracks in the housing, against each other and so can be inserted as a structural unit in the mold.

A casting of the individual segments, single-tooth windings and contacting device of a stator, in which the stator is formed from the potting compound could be referred to as a full encapsulation of the stator.

After casting, so the essential components of the stator are firmly joined together and form by casting a structural unit, which is so used in an electric machine. For this purpose, the potting compound has an electrically insulating property, since otherwise the electrically conductive components would be contacted with one another.

Here, in particular, the single-tooth windings may have been contacted before casting with the contacting device, so that the contact points of the single-tooth windings are embedded with the switching ring in the potting compound and are insulated to the outside. However, the encapsulant must not interrupt the electrical contact between single-tooth windings and the switching ring during casting.

Alternatively, the single-tooth windings could also be contacted only after casting with the contacting device, wherein during potting it must be ensured that the contacting points remain freely accessible and are not potted by the potting compound. For this purpose, in particular in the mold holding devices for receiving Drahtendbereichen the single-tooth windings may be present, which at the same time hold the switching rings and / or copper tracks in the mold and thus protect this area from the potting compound. The holding devices can be easily removed from the molded stator again after casting and by the resulting free area on the switching ring and the winding wires contacting the single-tooth windings with the switching ring even after the casting of the stator is still possible.

By freely accessible contact points of the single-tooth windings on the stator, which are not covered by potting compound contacting problems can also be corrected and eliminated afterwards.

The contacts can be created both before the casting, as well as after the casting.

Contacting the single-tooth windings with the contacting device before encapsulation would have an advantage in good accessibility of the contact points and a contact after encapsulation would have an advantage in a stable connection of the individual segments with single-tooth windings to a stator and an associated simple stable handling of the stator during the contacting.

A stator having a stator carrier produced according to the invention by means of encapsulation may, in an advantageous development, also have a cooling device.

In particular, the cooling device is advantageously designed as cooling channels on the outside of the stator carrier formed by the potting compound. For this purpose, a casting has formations on the region forming the circumference of the stator, which generate a channel structure in the casting compound. The channel structure on the circumferential outer side of the stator can be used to cool the stator and thus to cool the stator.

For this purpose, the cooling channels can essentially circulate the stator carrier in the circumferential direction and be arranged in parallel or in spiral form.

Alternatively, the cooling channels can essentially also run continuously or meandering in the axial direction.

But there are also other mixed forms of said cooling channel arrangements possible.

In particular, the cooling channels can form a cooling system with a housing of the electrical machine, wherein the cooling channels can terminate with the housing and form closed cooling lines or not complete all cooling channels with the housing and so individual cooling channels can exchange a cooling medium by flooding each other.

In an alternative embodiment of a stator according to the invention, the cooling device has, in particular, cooling lines in the potting compound of the stator carrier. The cooling lines have been cast during casting in the stator and are arranged in the stator so that lead at least one inlet and a drain of the cooling lines from the stator.

A line system of the cooling lines can in particular be prefabricated and inserted as a prefabricated component in a casting mold of the stator and cast with the stator.

Alternatively, individual cooling lines may have been inserted into a casting mold of the stator, which are connected to a cooling line system only after the casting on the finished molded stator.

An arrangement of the cooling lines in the stator can extend substantially in the axial direction, here from a first side, the cooling lines are flooded and on a second side, the cooling lines have a drain or the cooling lines enclose the stator at least partially in the circumferential direction, the cooling lines spiral or meandering in the interior of the stator can be arranged.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 schematically a perspective view of a stator for an electric machine and

2 schematically a perspective view of a single tooth segment of a stator for an electric machine.

Corresponding parts are provided in all figures with the same reference numerals.

1 schematically shows a perspective view of a stator 1 for example, designed as an electric motor and / or electric generator electric machine and 2 schematically a perspective view of a single tooth segment 2 for such a stator 1 , Based on these figures, a method of manufacturing the stator will be described below 1 explained in more detail.

In the prior art, it is customary to join individual teeth of an electric motor stator and then press them into a metallic hollow cylindrical carrier designed as a pot, casting, deep-drawn part or extruded part or into a carrier made by a cutting process. This preparation of the carrier is complicated and expensive and the carrier also has a high weight. Furthermore, a high production quality of the individual teeth is required, since fault tolerances of the individual teeth add up over their sum and a maximum upper limit for pressing the individual teeth into the carrier due to the fixed circumference must not be exceeded. This leads to high production costs in such prior art manufacturing processes. In addition, the insertion of the individual teeth results in high joining tolerances.

The process described below for the production of the stator 1 On the other hand, it is much simpler and cheaper to carry out, as there is a lower production quality of the single tooth segments 2 and higher tolerances allowed. In this case, by means of the method, a stator 3 manufactured, by means of which the single tooth segments 2 be pressed so that these in the form of a stator ring 4 held together and a sufficient support of a torque transmission of the stator ring 4 on the stator carrier 3 is possible.

The in 1 illustrated stator 1 includes a plurality of in 2 single tooth segments shown 2 , In the example shown here, each of these single tooth segments exists 2 from only one Statoreinzelzahn, but it can in other embodiments, but also single tooth segments 2 are used, which are already formed from a plurality of Statoreinzelzähnen.

The single tooth segments 2 become the stator ring 4 assembled, clamped together, arranged in a casting tool, not shown here, preferably in an injection mold and at least partially encapsulated with a potting compound such that the stator 3 is formed, which, as in 1 represented, the single tooth segments 2 encloses on an outer periphery, so that they are clamped together and held in Statorringform. It works by clamping the single tooth segments 2 , possibly additionally supported by the casting tool, during the casting at any time a sufficient pressure on the single tooth segments 2 to position them in their final position. About the stator carrier produced in this way 3 can the single tooth segments 2 be attached to other facilities of the electrical machine.

To get a good torque transfer from the single tooth segments 2 on the stator carrier 3 ensure the single tooth segments 2 preferably in back areas 5 , which the trainees Statorträger 3 are facing and are to be encapsulated with the potting compound to the single tooth segments 2 with the trainees stator carrier 3 to connect, corresponding formations 6 on, in which the potting compound can flow. In this way, after a complete curing a strong form-fitting, cohesive by pouring and by the compression of the single tooth segments 2 by means of the stator carrier 3 also non-positive connection between the stator 3 and the single tooth segments 2 ensured. In an advantageous embodiment of the method, moreover, the casting tool is designed such that during the casting of the stator 3 in this sufficient cooling channels for cooling the single tooth segments 2 be formed, which in the operation of the electric machine by a cooling medium, such as transmission oil, flows through or can be flowed through.

As potting compound preferably plastic is used. Alternatively, however, other materials may be used for the process, for example, resins. The potting compound, in particular the plastic, allows compared to known from the prior art supports made of metal a significant weight reduction and cost reduction, since plastic is much cheaper than metal and eliminates the costly and expensive production of the metallic carrier. In addition, for casting the single tooth segments 2 With the potting compound even low Vergusstemperaturen sufficient, so that damage to the single tooth segments 2 is avoided during potting.

The method enables a stable connection of the single tooth segments 2 on the stator carrier 3 with few process steps. In addition, the method allows compensation of tolerances of the single tooth segments 2 because of the stator carrier 3 does not have a fixed circumference in which the single tooth segments 2 must be pressed, but to the strained individual tooth segments 2 is poured around and thereby adapts perfectly to these. In addition, by biasing the single tooth segments 2 and the casting under formation of the stator 3 minimizes the joining tolerances.

For clamping the single tooth segments 2 to press these against each other and during the potting with the potting compound in the form of the stator ring 4 to hold, at least one biasing device not shown here is advantageously used. This biasing device is designed, for example, as a split disk hub or as a slotted lever hub. It is also possible to use a plurality of identical or differently configured pretensioning devices.

The biasing device may after the manufacture of the stator 1 remain in this, ie, the biasing device is poured into the potting compound, so at least partially enclosed by this. As a result, after casting, an additional distortion of the single tooth segments 2 allows, as these permanently, ie even after the completion of the stator 1 , not only through the stator 3 , but also be braced by the biasing device. In this way, the potting compound, ie the stator formed from the potting compound 3 , relieved.

This allows the stator carrier 3 make smaller, so that a reduction of the electric machine is made possible, whereby a smaller space requirement for the electric machine is required at a respective operating position. This is particularly advantageous, for example, when using the electrical machine embodied, for example, as an electric motor and / or electrical generator in a vehicle, since only a limited installation space is available here.

In a particularly advantageous embodiment of the method, as the potting compound preferably plastic or another material is used which has insulating properties, the single tooth segments 2 encapsulated with the potting compound in such a way that even windings 7 the single tooth segments 2 be encapsulated with the potting compound. This is in the in 1 illustrated embodiment of the stator 1 shown, in which the windings 7 the single tooth segments 2 , which at the in 2 single tooth segment shown 2 still free, covered by the potting compound and therefore are no longer visible.

To the Umgießen also the windings 7 the single tooth segments 2 during the formation of the stator carrier 3 to allow with the potting compound, a corresponding shape of the potting tool is required, so that not only the back areas 5 the single tooth segments 2 but also their windings 7 can be encapsulated with the potting compound. In this way, a separate process step, ie an isolation or Casting the windings 7 saved, since this in the same process step with the formation of the stator 3 is carried out. As this separate process step in each case for each single tooth segment 2 would be carried out separately, in this way for each single tooth segment 2 each saved such a separate process step. This leads to a considerable manufacturing time and manufacturing cost reduction.

LIST OF REFERENCE NUMBERS

1

stator

2

Single ratchet

3

stator

4

stator

5

back

6

formation

7

winding

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2256901 A2 [0002]

Claims (9)

Method for producing a stator ( 1 ) for an electrical machine, characterized in that a plurality of single tooth segments ( 2 ) to a stator ring ( 4 ) are assembled and encapsulated with a potting compound at least in areas such that a stator ( 3 ) is formed. Method according to claim 1, characterized in that the individual tooth segments ( 2 ) are at least partially encapsulated with a potting compound formed as a plastic. Method according to claim 1 or 2, characterized in that the individual tooth segments ( 2 ) are clamped together by means of at least one biasing device. Method according to claim 3, characterized in that the individual tooth segments ( 2 ) are clamped together by means of at least one biasing device designed as a split disk hub or slotted lever hub. A method according to claim 3 or 4, characterized in that the biasing device is at least partially encapsulated with the potting compound. Method according to one of the preceding claims, characterized in that the individual tooth segments ( 2 ) are encapsulated with the potting compound in such a way that windings ( 7 ) of the single tooth segments ( 2 ) are encapsulated with the potting compound. Method according to one of the preceding claims, characterized in that the individual tooth segments ( 2 ) are encapsulated with the potting compound such that a contacting device is encapsulated with the potting compound. Stator ( 1 ) for an electrical machine produced by a method according to one of claims 1 to 7, comprising a plurality of to a stator ring ( 4 ) assembled, against each other and with a potting compound at least partially encapsulated single tooth segments ( 2 ), wherein by the potting compound a stator ( 3 ) is trained. Stator ( 1 ) for an electric machine according to claim 8, characterized in that the stator carrier formed from potting compound ( 3 ) Cooling devices, in particular arranged on an outer side cooling channels.

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