DE102017011969A1 - Method for producing a rotor unit for an electric motor - Google Patents

Abstract

The invention relates to a method for producing a rotor unit (10) for an electric motor, in particular a motor vehicle, comprising at least the following steps: - providing a rotor segment stack (20) on which a plurality of magnetic elements (22) are arranged; - inserting the rotor segment stack ( 20) in a mold (60); and - casting a rotor shaft (30) whereby the rotor shaft (30) is connected to the rotor segment stack (20) to the rotor unit (10).

Description

The invention relates to a method for producing a rotor unit for an electric motor.

In electric motors known from the prior art, respective laminated cores of a rotor are shrunk or pressed onto a rotor carrier or a rotor shaft. As a rule, at least two consecutive process steps are carried out, the first step being the manufacture of the rotor shaft and the laminated cores. In a subsequent assembly, the laminated cores, which can be combined to form a rotor segment stack, are connected to the rotor shaft to form a rotor unit.

From the EP 2 390 986 A1 is a permanent magnet rotor for an electric motor with a central shaft and a surrounding rotor body known. The rotor body is formed of a plastic material with embedded magnetic particles and cast onto the shaft such that it is connected to the shaft via a plurality of individual, circumferentially spaced connecting webs.

From the DE 102 56 399 A1 For example, a method of manufacturing a squirrel cage for use in an electric motor is known. Here, a rotor core formed of a plurality of stacked sheets is provided with through holes, and a die casting of molten conductive material is performed to form a rotor conductor in at least a part of the through holes while integrally forming left and right shorting rings on the left and right ends of the rotor core to mold. During die casting, a rotor shaft is integrally molded to the left and right shorting rings.

Object of the present invention is to provide a method of the type mentioned, by means of which a rotor unit can be produced under very little effort.

This object is achieved by a method having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

• - Bereitstellen eines Rotorsegmentstapels an welchem eine Mehrzahl an Magnetelementen angeordnet sind;
• - Einlegen des Rotorsegmentstapels in eine Gussform und
• - Gießen einer Rotorwelle, wodurch die Rotorwelle mit dem Rotorsegmentstapel zu der Rotoreinheit verbunden wird.

A method for producing a rotor unit for an electric motor, in particular a motor vehicle, by means of which the rotor unit can be produced with particularly little effort, comprises at least the following steps:

• - Providing a rotor segment stack on which a plurality of magnetic elements are arranged;
• - Inserting the rotor segment stack in a mold and
• Casting a rotor shaft, whereby the rotor shaft is connected to the rotor segment stack to the rotor unit.

The rotor segment stack may comprise a plurality of laminated cores, which may also be referred to as rotor segment main body. On the rotor segment stack or on the rotor segment main bodies, the magnetic elements can be fixed, for example, positively and additionally or alternatively non-positively, wherein the rotor segment stack may also include a short-circuit cage. After inserting the rotor segment stack in the mold, which can also be referred to as a casting tool, the casting of the rotor shaft by which the rotor shaft is connected to the rotor segment stack to the rotor unit takes place. In other words, therefore, the individual laminated cores or the rotor segment main body are connected to the rotor shaft.

In contrast to methods known from the prior art in which components of an electric motor are cast onto an existing rotor shaft, in the present method the rotor shaft is cast and thereby connected to the rotor segment stack with the rotor unit. As a result, by means of a segment stack contour of the rotor segment stack, a corresponding shaping of the rotor shaft adapted to the rotor segment stack can be achieved during casting of the rotor shaft, whereby the casting can be carried out with particularly little effort. Overall, thereby costs in production and assembly can be saved, since the assembly of the rotor shaft on the rotor segment stack during the casting of the rotor shaft, that is in other words during the manufacture of the rotor shaft is performed. The rotor shaft can thus be manufactured as an integrally cast rotor shaft by casting and simultaneously connected to the rotor segment stack.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing (s). The features and combinations of features mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures are not only in the respectively indicated combination but also in other combinations or usable in isolation, without departing from the scope of the invention.

• 1a eine Perspektivansicht eines Rotorsegmentgrundkörpers;
• 1b eine Perspektivansicht eines Magnetelements;
• 1c eine Perspektivansicht auf den Rotorsegmentgrundkörper mit integrierten Magnetelementen;
• 2a eine Perspektivansicht eines Rotorsegmentstapels, welcher aus einer Mehrzahl an Rotorsegmentgrundkörpern mit eine Mehrzahl an integrierten Magnetelementen gebildet ist;
• 2b eine Seitenansicht des Rotorsegmentstapels, welcher in einer geschnitten dargestellten Gussform angeordnet ist;
• 2c eine weitere Seitenansicht des Rotorsegmentstapels, welcher in der geschnitten dargestellten Gussform angeordnet ist, wobei eine Rotorwelle gegossen und dadurch in den Rotorsegmentstapel integriert wird, wodurch die Rotorwelle mit dem Rotorsegmentstapel zu einer Rotoreinheit verbunden wird;
• 2d eine Seitenansicht der Rotoreinheit als Rohteil;
• 2e eine weitere Seitenansicht der Rotoreinheit als Fertigteil;
• 3a eine Schnittdarstellung einer Variante der Rotoreinheit als Rohteil;
• 3b eine Schnittdarstellung der in 3a gezeigten Rotoreinheit als Fertigteil;
• 3c eine perspektivische Detailansicht eines Teilbereichs der Rotoreinheit, wobei eine Strebe der Rotorwelle in eine Aussparung eines einzelnen Rotorsegmentgrundkörpers des Rotorsegmentstapels zur Drehmomentübertragung eingreift;
• 4a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 4b eine weitere Schnittdarstellung der in 4a gezeigten Variante der Rotoreinheit als Fertigteil;
• 4c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 4b gezeigten Variante;
• 5a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 5b eine weitere Schnittdarstellung der in 5a gezeigten Variante der Rotoreinheit als Fertigteil;
• 5c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 5b gezeigten Variante;
• 6a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 6b eine weitere Schnittdarstellung der in 6a gezeigten Variante der Rotoreinheit als Fertigteil;
• 6c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 6b gezeigten Variante;
• 6d eine Perspektivansicht der Rotorwelle der in 6b gezeigten Variante;
• 7a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 7b eine weitere Schnittdarstellung der in 7a gezeigten Variante der Rotoreinheit als Fertigteil;
• 7c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 7b gezeigten Variante;
• 7d eine Perspektivansicht der Rotorwelle der in 7b gezeigten Variante;
• 8a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 8b eine weitere Schnittdarstellung der in 8a gezeigten Variante der Rotoreinheit als Fertigteil;
• 8c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 8b gezeigten Variante;
• 8d eine Perspektivansicht der Rotorwelle der in 8b gezeigten Variante;
• 9a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 9b eine weitere Schnittdarstellung der in 9a gezeigten Variante der Rotoreinheit als Fertigteil;
• 9c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 9b gezeigten Variante;
• 9d eine Perspektivansicht der Rotorwelle der in 9b gezeigten Variante;
• 10a eine Schnittdarstellung einer weiteren Variante der Rotoreinheit als Rohteil;
• 10b eine weitere Schnittdarstellung der in 10a gezeigten Variante der Rotoreinheit als Fertigteil;
• 10c eine Draufsicht auf einen einzelnen Rotorsegmentgrundkörper der in 10b gezeigten Variante;
• 10d eine Perspektivansicht der Rotorwelle der in 10b gezeigten Variante;
• 11a eine Perspektivansicht auf eine weitere Variante des Rotorsegmentgrundkörpers; und
• 11b eine Perspektivansicht auf eine weitere Variante des Rotorsegmentstapels, welcher aus einer Mehrzahl von Rotorsegmentgrundkörpern gemäß 11a gebildet ist.

Showing:

• 1a a perspective view of a rotor segment main body;
• 1b a perspective view of a magnetic element;
• 1c a perspective view of the rotor segment main body with integrated magnetic elements;
• 2a a perspective view of a rotor segment stack, which is formed from a plurality of rotor segment main bodies with a plurality of integrated magnetic elements;
• 2 B a side view of the rotor segment stack, which is arranged in a die shown cut;
• 2c a further side view of the rotor segment stack, which is arranged in the die shown cut, wherein a rotor shaft is poured and thereby integrated into the rotor segment stack, whereby the rotor shaft is connected to the rotor segment stack to a rotor unit;
• 2d a side view of the rotor unit as a blank;
• 2e a further side view of the rotor unit as a finished part;
• 3a a sectional view of a variant of the rotor unit as a blank;
• 3b a sectional view of in 3a shown rotor unit as a finished part;
• 3c a detailed perspective view of a portion of the rotor unit, wherein a strut of the rotor shaft engages in a recess of a single rotor segment main body of the rotor segment stack for torque transmission;
• 4a a sectional view of another variant of the rotor unit as a blank;
• 4b another sectional view of in 4a shown variant of the rotor unit as a finished part;
• 4c a plan view of a single rotor segment main body of in 4b shown variant;
• 5a a sectional view of another variant of the rotor unit as a blank;
• 5b another sectional view of in 5a shown variant of the rotor unit as a finished part;
• 5c a plan view of a single rotor segment main body of in 5b shown variant;
• 6a a sectional view of another variant of the rotor unit as a blank;
• 6b another sectional view of in 6a shown variant of the rotor unit as a finished part;
• 6c a plan view of a single rotor segment main body of in 6b shown variant;
• 6d a perspective view of the rotor shaft of in 6b shown variant;
• 7a a sectional view of another variant of the rotor unit as a blank;
• 7b another sectional view of in 7a shown variant of the rotor unit as a finished part;
• 7c a plan view of a single rotor segment main body of in 7b shown variant;
• 7d a perspective view of the rotor shaft of in 7b shown variant;
• 8a a sectional view of another variant of the rotor unit as a blank;
• 8b another sectional view of in 8a shown variant of the rotor unit as a finished part;
• 8c a plan view of a single rotor segment main body of in 8b shown variant;
• 8d a perspective view of the rotor shaft of in 8b shown variant;
• 9a a sectional view of another variant of the rotor unit as a blank;
• 9b another sectional view of in 9a shown variant of the rotor unit as a finished part;
• 9c a plan view of a single rotor segment main body of in 9b shown variant;
• 9d a perspective view of the rotor shaft of in 9b shown variant;
• 10a a sectional view of another variant of the rotor unit as a blank;
• 10b another sectional view of in 10a shown variant of the rotor unit as a finished part;
• 10c a plan view of a single rotor segment main body of in 10b shown variant;
• 10d a perspective view of the rotor shaft of in 10b shown variant;
• 11a a perspective view of a further variant of the rotor segment main body; and
• 11b a perspective view of another variant of the rotor segment stack, which consists of a plurality of Rotorsegmentgrundkörpern according to 11a is formed.

1a shows a rotor segment main body 24 with a plurality of receiving openings, in each of which, in 1b shown magnetic element 22 can be inserted and fixed to the rotor segment main body 24 accordingly with the magnetic elements 22 to equip, as in 1c is shown. The rotor segment main body 24 can also be referred to as a rotor segment and be formed for example as a laminated core.

A plurality of rotor segment main bodies 24 with the respective magnetic elements 22 can become one, in 2a shown rotor segment stack 20 are arranged, whereby the rotor segment stack 20 at least substantially, for example, can be constructed in a hollow cylindrical shape. The rotor segment stack 20 can thereby for a method for producing a in Fig. 2d and 2e shown rotor unit 10 be provided, wherein the rotor segment stack 20 with the plurality of magnetic elements 22 is provided. The rotor segment stack 20 can total before it is made available from the Rotorsegmentgrundkörpern 24 and the plurality of magnetic elements 22 be prepared by the plurality of magnetic elements 22 connected to the rotor segment main bodies 24 and the rotor segment main bodies 24 are then strung together to thereby the rotor segment stack 20 as shown in the synopsis of Fig. 1c and 2a is apparent. The rotor segment stack 20 can also be referred to as a so-called rotor segment stack. In the method of manufacturing the rotor unit 10 becomes the provided rotor segment stack 20 in a mold 60 inserted as schematically in 2 B is shown. This is followed by casting a rotor shaft 30 the rotor unit 10 , causing the rotor shaft 30 with the rotor segment stack 20 is connected to the rotor unit, as shown schematically in FIG 2c is shown.

2d shows the rotor unit 10 with the rotor segment stack 20 in which the rotor shaft 30 is integrated and immediately after casting exists as a casting blank. The rotor unit 10 can after casting the rotor shaft 30 be balanced, so in other words subjected to a balancing method, which is not shown in the present case, however. Furthermore, a fine machining of the rotor unit 10 take place, for example, by machining the rotor shaft 30 a spline 40 on the rotor shaft 30 can be provided as in 2e is shown. 2e shows the rotor unit 10 as a finished part after balancing and after the formation of the spline 40 on the rotor shaft 30 , In this state, the present as a finished part rotor unit 10 be used as a rotor in an electric motor not shown here.

3a shows a blank (cast blank) and 3b another finished part of another variant of the rotor unit 10 , Around a cavity 32 in the rotor shaft 30 can be used to cast the rotor shaft 30 a casting core not shown here can be used. The casting core may be made of sand with integrated steel rod for storage during this casting of the rotor shaft 30 to be provided. 3c shows that on the rotor shaft 30 when casting respective grooves 34 can be produced, which for torque transmission in corresponding recesses 26 in the respective Rotorsegmentgrundkörpern 24 can intervene. This is a low-cost, non-rotatable mounting of the rotor segment stack 20 on the rotor shaft 30 allows. Through the casting core, the cavity 32 be particularly large dimensions, causing the rotor shaft 30 and thus the rotor unit as a whole 10 may have a particularly low weight. Fig. 3a and 3b show the one-piece design of the rotor unit 10, which can be installed under very little effort in the assembly of the electric motor.

4a shows a blank and 4b a finished part of a further variant of the rotor unit 10, wherein the rotor unit 10 in the present case is designed in several parts. The rotor shaft 30 in this case comprises a first shaft element designed as a cover 36 by means of which the cavity 32 can be closed on one side. The cavity 32 is in a second wave element 38 the rotor shaft 30 integrated, wherein the rotor segment stack 20 on the second shaft element 38 is arranged. The in Fig. 4a and 4b shown, two-part training is possible, the casting of the rotor shaft 30 used casting core, by means of which the cavity 32 in the rotor shaft 30 is produced as a sliding tool for demolding the rotor unit 10 after casting the rotor shaft 30 to use. This makes a particularly simple demolding possible.

The two wave elements 36 . 38 can be joined by screwing or friction welding, just to name a few. The two-part design allows the use of outer molds and the casting core as a sliding tool, wherein the outer molds and the casting core can be cooled in an advantageous manner, to solidify the rotor shaft 30 to accelerate after pouring. Furthermore, the two-part design of the rotor unit allows 10 or the rotor shaft 30 a renunciation of lost forms. In other words, it is therefore possible to dispense with the casting core as when demolding the rotor unit 10 to form destructive sand core. Due to the two-part design is further an internal processing, so accessibility of the cavity 32 allows, for example, the balancing from the direction of the cavity 32 and thus on an inner side of the rotor shaft 30 can be carried out.

4c again shows the torque transmission, wherein the on the second shaft element 38 the rotor shaft 30 arranged grooves 34 in, on the rotor segment stack 20 or at the, in the individual rotor segment main body 24 integrated recesses 26 engage.

5a shows a blank and 5b a finished part of a further variant of the rotor unit 10, wherein the casting core as a sliding tool for demolding the rotor unit 10 after casting the rotor shaft 30 can be used, and in which the rotor segment stack 20 as an alternative laminated core with compared to in Fig. 4a and 4b shown variant of smaller inner diameter is formed. In this variant, the molds used for the production or the casting core used as a slide can be cooled, wherein the in Fig. 5a and 5b shown variant of the rotor unit 10 can be produced in one piece. The grooves 34 on the rotor shaft 30 can, as in 5c shown, generally have a dovetailed contour and thereby to form an undercut with the corresponding recesses 26 on the rotor segment stack 20 or on the rotor segment main bodies 24 engage.

6a shows a blank and 6b a finished part of a further variant of the rotor unit 10, wherein as the casting core (mold) cover slats can be used. When casting the rotor shaft 30 each outer molds can be cooled, with optionally an additional compression of the sheet metal pact (rotor segment stack 20 ) due to when casting the rotor shaft 30 occurring shrinkage may be required. 6c shows that for torque transmission between the rotor segment stack 20 and the individual rotor segment main bodies 24 and the rotor shaft 30 respective slots 26 formed as slots may be provided, in which respective struts 42 the rotor shaft 30 can intervene. 6d shows the rotor shaft 30 with the respective struts 42 for this as a single part.

7a shows a blank and 7b a finished part of another variant of the rotor unit 10, which is also made in one piece and with cover slats as a mold. The outer molds can also be cooled, wherein for the manufacture of the rotor unit 10 likewise an additional compression of the sheet metal pact (rotor segment stack 20 ) with the rotor shaft 30 to compensate for shrinkage may be required. The rotor segment main body 24 may be formed as an alternative sheet metal part, wherein the torque transmission in turn by struts 42 and corresponding recesses 26 formed as elongated holes can take place, as in FIG 7c is recognizable. 7d shows the rotor shaft 30 with the struts 42 as a single item.

8a shows a blank and 8b a finished part of another variant of the rotor unit 10, which can be produced with a particularly large material savings. In this variant, the outer molds can be cooled and it can be an additional compression of the Blechpaktes (rotor segment stack 20 ) with the rotor shaft 30 be necessary to compensate for shrinkage occurring during casting. In this variant, uniform individual sheets can be used, wherein a total of a one-piece casting concept with metal lids as a mold and the slots (recesses 26) for torque transmission through the struts 42 can be used. Before casting, the individual rotor segment base bodies 24 designed as sheet metal covers can be welded together. 8c shows one of belonging to this variant rotor segment main body 24 and 8b the belonging to this variant rotor shaft 30 with the struts 42 ,

9a shows a blank and 9b a finished part of another variant of a rotor unit 10 , which can be produced with a particularly large material savings. Again, the outer molds can be cooled, with an additional compression of the Blechpaktes (rotor segment stack 20 ) with the rotor shaft 30 may be required to compensate for shrinkage. Again, uniform individual sheets can be used, with a smooth oil supply, for example, in the cavity 32 for internal cooling of the sheet metal pact (rotor segment stack 20 ). The rotor shaft formed in two parts in this variant 30 can at its second shaft element 38 at which the rotor segment stack 20 is arranged in the present case, a bearing seat for receiving a, in the present case designed as a ball bearing roller bearing 50 exhibit. The second wave element 36 can by means of the rolling bearing 50 rotatable with the second shaft member 38 be connected, as from the synopsis of Fig. 9b and 9c is recognizable. Also in this variant, the slots formed as slots 26 and the struts serve 42 the rotor shaft 30 for torque transmission, as in 9c is recognizable. 9d shows the rotor shaft 30 this variant as a single part.

10a shows a blank and 10b a finished part of another variant of a rotor unit 10 , which can be produced under a particularly large material savings. Also in this variant, the outer molds can be cooled. In addition, in this variant, an additional compression of the sheet metal pact (rotor segment stack 20 ) with the rotor shaft 30 be necessary to compensate for shrinkage. In this variant, uniform individual sheets can be used, with a problem-free oil supply into the cavity 32 and thus an internal cooling of the sheet metal pact (rotor segment stack 20 ). Also in this variant, the second shaft element 38 partially for receiving the ball bearing designed as a rolling bearing 50 be formed. For torque transmission are filled grooves 34 , which with the recesses 36 to be engaged, as in 10c is recognizable. 10d again shows the belonging to this variant rotor shaft 30 as a single part.

11a shows again a variant of the rotor segment main body 24 which has the recesses 26 on an inner circumference. In the rotor segment main body 24 are the magnetic elements 22 integrated. 11b shows a further variant of the rotor segment stack 20 with the plurality of rotor segment main bodies 24 into which the magnetic elements 22 are integrated.

In summary, by the present method, a component design of the rotor unit 10 with particularly high freedom of movement. Furthermore, lightweight construction concepts can be used in the production of the rotor unit with particularly little effort 10 be used, wherein joining processes for producing any shaft-hub connections between the rotor shaft 30 and the rotor segment stack 20 can be omitted. The rotor shaft 30 can be produced simultaneously by casting and with the rotor segment stack 20 connectable, in contrast to known from the prior art, multipart and thus built rotor shafts. The manufacture of the rotor unit 10 According to the present method also allows optimal cooling of the rotor unit 10 wherein the rotor shaft can be made with optimized torsional rigidity and flexural rigidity. In addition, the rotor shaft 30 with optimized torsional natural frequency, so that the rotor unit 10 Overall, it has particularly favorable NVH properties (noise vibration harshness).

LIST OF REFERENCE NUMBERS

10

rotor unit

20

Rotor segment stacks

22

magnetic element

24

Rotor segment body

30

rotor shaft

32

cavity

34

groove

36

first shaft element

38

second shaft element

40

spline

42

strut

50

roller bearing

60

mold

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 2390986 A1 [0003]
• DE 10256399 A1 [0004]

Claims (4)

Method for producing a rotor unit (10) for an electric motor, in particular a motor vehicle, comprising at least the following steps: - Providing a rotor segment stack (20) on which a plurality of magnetic elements (22) are arranged; - Inserting the rotor segment stack (20) in a mold (60); and - Casting a rotor shaft (30), whereby the rotor shaft (30) with the rotor segment stack (20) is connected to the rotor unit (10). Method according to Claim 1 characterized in that the rotor segment stack (20) is made prior to providing it with rotor segment main bodies (24) and the plurality of magnetic elements (22) by connecting the plurality of magnetic elements (22) to the rotor segment main bodies (24) and the rotor segment main bodies (24) are then strung together to thereby produce the rotor segment stack (20). Method according to Claim 1 or 2 , characterized in that the rotor unit (10) after the casting of the rotor shaft (30) is balanced. Method according to one of the preceding claims, characterized in that a casting core used for casting the rotor shaft (30), by means of which a cavity (32) is produced in the rotor shaft (30), as a sliding tool for demolding of the rotor unit (10) after casting the rotor shaft (30) is used.

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