DE102010021595A1 - Laminated core, in particular for the rotor of an electric motor - Google Patents

Abstract

The invention relates to a laminated core (2), in particular for the rotor (1) of an electric motor, consisting of individual laminations (3) stacked one above the other, with a number of pocket segments (14), which in the stacking direction (11) have receiving pockets (9) for permanent magnets (9) that are open on the circumference. 10) form. In each case two individual sheets (3) lying one against the other in the sheet stack (2) are rotated relative to one another by an angle α, which is determined by the arc spacing of two adjacent clamping teeth (4) of a single sheet. A straight number (11) is formed on each individual sheet (3), each clamping tooth (4) together with one of its two directly adjacent clamping teeth (4) a pocket segment (14) and together with the other directly adjacent clamping tooth (4) Sheet metal peripheral section (15) laterally limited. The pocket segments (14) and the sheet metal peripheral sections (15) follow one another alternately in the peripheral direction (12).

Description

The invention relates to a laminated core, in particular for the rotor of an electric motor, of stacked individual sheets with a number of pocket segments which form in the stacking direction circumferentially open receiving pockets for permanent magnets.

An electric motor with such a laminated core is used for example as a small motor in the motor vehicle sector and there in particular as a steering motor or as an adjustment. Whereas in the case of an electric motor as a so-called external rotor motor, a rotor concentrically surrounds a stationary stator, in the case of an internal rotor motor, a stator is arranged coaxially with the rotating rotor (rotor) to form an air gap.

If the rotor carries a number of permanent magnets or permanent magnets, and if the stator comprises a coil winding which is wired, for example, in a three-phase manner and which is driven, for example, by pulse-side-modulated currents, a permanently excited brushless DC motor is provided. If the rotor is provided with the magnets (permanent magnets), they can be held by clamping or gluing on the laminated core of the rotor. The laminated core here consists of a large number of stacked individual sheets (sheet metal laminates).

From the DE 100 09 151 C2 It is known to provide peripherally mounted on a rotor electric motor clamping elements which initially protrude radially from a laminated core and are bent after the insertion of permanent magnets in the circumferential direction, so that the bent ends engage in recesses of the magnets and thus hold them on Blechparket. In the production of such a laminated core, however, sheet metal laminates must be manufactured with and without such clamping elements or projections.

The DE 10 2005 044 218 A1 discloses a rotor whose laminated core has circumferentially open pockets or grooves for permanent magnets. These magnets are fixed in the pockets with the help of an adhesive. The requirements for this type of fastening are very high due to the centrifugal forces and the environmental influences that the electric motor is exposed to. This can undesirably affect the life of the electric motor.

The invention has for its object to further improve a laminated core of the type mentioned in that a reliable and permanent fixation of the magnets is ensured in a simple manner.

This object is achieved according to the invention by the features of claim 1. The dependent claims contain in part advantageous and in part self-inventive developments of this invention.

One of the teaching of this invention corresponding laminated core is constructed of stacked individual sheets, each having a plurality of pocket segments, which form in the stacking direction circumferentially open receiving pockets for permanent magnets. An even number of clamping teeth is formed perpendicular to the stacking direction on the individual sheets. These clamping teeth act on the one hand in pairs as a lateral boundary of either a pocket segment or a sheet metal peripheral portion and on the other hand individually as separating elements each between a pocket segment and a sheet metal peripheral portion. Accordingly, the pocket segments, which are each part of a receiving pocket in the laminated core, and the sheet metal peripheral sections, which serve for the spatial separation of the pocket segments in the manner of a common division, arranged alternately in the circumferential direction.

The identical individual sheets are stacked in a dual sequence (ABAB, etc.). In this case, every other single sheet (A) is rotated by an angle α, which is given by the arc distance of two clamping tooth neighbors, against the other intermediate individual sheets (B). As a rotation axis is here to be considered parallel to the stacking direction center axis of the laminated core. It should be mentioned at this point that, depending on the electric motor specification, deviating sequences can also be advantageous. A modification would be, for example, a stacking sequence in which each two successive stacked in the stacking direction and similarly stacked individual sheets form a single sheet pair and in which the individual sheet pairs are rotated in an alternating sequence by the angle α against each other (AABBAABB, etc.).

As a result of the selected stacking sequence, the pocket segments of each second individual sheet (A) and the sheet metal peripheral sections of the remaining individual sheets (B) serving for the spatial separation lie directly above one another in the stacking direction. The same applies to the spatial separation serving for sheet metal peripheral sections of each second individual sheet (A) and the pocket segments of the remaining intermediate individual sheets (B). As a result, exactly every second single sheet in the laminated core contributes a pocket segment to the formation of an exemplary considered receiving pocket. Whereas the other intermediate individual sheets each contribute a pocket segment for the two receiving pockets which are directly adjacent in the circumferential direction. When inserting the Permanent magnets in the receiving pockets designed in this way, the clamping teeth are plastically deformed. This ensures a reliable fixation of the magnets on the laminated core.

In a preferred embodiment, the clamping teeth are V-shaped with a respective directly adjacent pocket segment facing the first tooth flank and the corresponding pocket segment facing away second tooth flank and two circumferentially adjacent clamping teeth are each inclined in the opposite circumferential direction. As a result, two mutually inclined Klemmzahnnachbarn together with the intermediate circumferential end face of the individual sheet forming the respective pocket segment, while two mutually aneinanderbeschränten Klemmzahnnachbarn a Blechumfangsabschnitt, the spatially separated on both sides in the circumferential direction pocket segments spatially from each other so that the pocket segments of a single sheet after Type of a common division are arranged circumferentially. This shape allows a simplified production of the usually punching produced individual sheets.

In this connection, it is considered to be particularly advantageous if the spread angle β formed by the two tooth flanks is greater than 0 ° and preferably less than 25 °. Thus, on the one hand the necessary plastic deformability is ensured, which is to be exploited when inserting the permanent magnets to achieve a clamping action, and on the other hand, it is ensured that the clamping teeth are not overstressed due to the centrifugal forces occurring.

In a further preferred embodiment, the angle of inclination γ of each clamping tooth, which is formed by the first tooth flank and the peripheral, preferably flat, bottom of the pocket, is less than 90 ° and preferably greater than 75 °. As a result, an exclusively punctual loading of the brittle permanent magnets is avoided.

Moreover, a combination of spread angle and angle of inclination, which is specially matched to the permanent magnet material used and the permanent magnet shape, causes the unfavorable influence of the magnetic field by the clamping teeth to be kept to a minimum.

As an alternative to the functional differentiation of the individual sheet metal segments by means of clamping tooth inclination, the subdivision of these segments into pocket segments and sheet metal peripheral sections can also be achieved, inter alia, by an asymmetric clamping tooth form, provided that two directly adjacent clamping teeth are mirror-inverted to one another on the single sheet. For example, a trapezoidal clamping tooth shape with a primary tooth flank facing the respective adjacent pocket segment and a secondary tooth flank facing the sheet metal circumferential section is expedient.

Based on the design variant with V-shaped clamping tooth geometry, two angles are defined in this case by the tooth flanks of the approximately trapezoidal clamping tooth. On the one hand, the opening angle formed by the primary and the secondary tooth surface δ, which is preferably less than 90 ° and greater than 15 °, and on the other hand the clamping angle ε, which is formed by the primary tooth flank and the peripheral, preferably flat, bottom of the bag and preferably smaller 90 ° and greater than 75 °. Just as with the angle of spread and the angle of inclination, these specifications serve to determine the load capacity of the clamping teeth, to avoid a selective application of force to the brittle permanent magnets and to specify the change caused by the clamping teeth change of the magnetic field generated by the permanent magnet.

In a particularly advantageous embodiment, each permanent magnet is held positively in the final assembled state in the pocket segments of the corresponding receiving pocket. In this case, the forces acting on the magnet due to the frictional connection and the pressure forces caused by the centrifugal forces acting in the operating state are distributed over a larger contact surface on the magnet.

Furthermore, an embodiment is preferred in which a fastening means is introduced between each magnet-metal sheet contact surface pair. The fastener should have a supporting function and not replace the fixture achieved by clamping. Since the fastening means is preferably used after the introduction of the magnets, the clamping teeth serve in the course of the manufacturing process also for backlash-free prefixing of the magnets, until then the anchoring of the magnets is completed by means of the fastening means.

In this context, it is considered to be particularly advantageous if at least one recess between each pocket segment and the corresponding permanent magnet is provided for forming a magnetic sheet-contact surface clearance and filled in the final assembled state with the fastener. Since corresponding recesses on the magnet affect the magnetic field, corresponding recesses are preferably provided on the individual sheets. In particular, in the use of the fastener after the onset of the magnets can on this Way a favorable embedding of the fastener can be achieved.

In a particularly expedient embodiment in this regard, it is provided to position the recesses on the inner side of the pocket segment in the respective region of the two clamping teeth of each pocket segment.

To coat the permanent magnets with a, preferably produced by painting or powder coating, protective cover, since they are usually made of a brittle material and therefore are particularly shock-sensitive. Likewise, it is advantageous if the laminated core is sheathed with a preferably analogously generated protective cover. Thus, the laminated core can be protected from corrosion, which is particularly caused by humidity.

In a suitable development, it is finally provided to use one and the same material as a fastening means for generating the impact protection cover for the magnets and for generating the corrosion protection cover for the laminated core. As a result, only a single manufacturing process step is necessary to meet all three targets.

Embodiments will be explained in more detail with reference to several drawings. Show:

1 in a perspective view of an inventive laminated core with permanent magnets inserted,

2 the laminated core according to 1 without permanent magnets,

3 in perspective view a receiving pocket (clamping pocket) of the laminated core without permanent magnet,

4 in a perspective view of a receiving pocket (clamping pocket) of the laminated core with inserted permanent magnet,

5 a section V from 4 on a larger scale with a clamping tooth in a plan view,

6 in a plan view of an inventive laminated core without permanent magnets,

7 a section VII 6 on a larger scale with several clamping teeth in a plan view,

8th in a plan view of a single sheet according to the invention,

9 a section IX 8th on a larger scale with several clamping teeth in a plan view,

10 in a plan view of an inventive single sheet with alternative clamping tooth geometry,

11 a section XI 10 on a larger scale with several clamping teeth in a plan view,

12 in a plan view of an inventive laminated core of individual sheets with the alternative clamping tooth geometry without permanent magnets,

13 a section XIII 12 on a larger scale with several clamping teeth in a plan view,

14 in a perspective view of a receiving pocket (clamping pocket) of the laminated core of individual sheets with the alternative clamping tooth geometry without permanent magnet,

15 in a plan view on a larger scale a clamping tooth with the alternative geometry.

In 1 is a rotor 1 shown with a cylindrical basic shape, which is provided for a (not shown here) electric motor. According to the internal rotor motor principle, the rotor sits 1 in the final assembled state in a manner not shown on a shaft and is surrounded to form an air gap coaxially by a stator.

The basis for the rotor 1 forms an in 2 and 6 shown laminated core 2 from stacked single sheets 3 , The individual sheets 3 if you have the circumferentially positioned clamping teeth 4 disregard, together a straight prism with an isogonal decagon as a base.

Symmetrical about the central longitudinal axis 5 of the laminated core 2 there is a cylindrical material recess as a receptacle 6 for the shaft of the electric motor. To avoid unwanted rotation of the shaft against the laminated core 2 are ten parallel to the central longitudinal axis 5 extending locking grooves 7 with a trapezoidal cross section in the manner of a common division on the lateral surface of the receptacle 6 arranged.

The evenly distributed over the circumference of the prism side surfaces each form a flat pocket bottom 8th , Each side surface will bounded by two edges to which the directly adjacent two side surfaces join. Along these edges are clamping teeth 4 molded, which covers every pocket bottom 8th limit laterally and so, together with this, a subsequent due to their clamping effect also referred to as a clamping pocket receiving pocket 9 form into which a permanent magnet 10 is used. In 3 and 7 is exemplified in each case such a receiving bag 9 shown enlarged.

The formation of the laminated core 2 used individual sheets 3 wise, as in 8th it can be seen, in each case an even number of clamping teeth 4 on, perpendicular to the stacking direction 11 are formed. Two each in the circumferential direction 12 adjacent and each other inclined clamping teeth 4 mold together with the intermediate circumferential end face 13 of the single sheet 3 a bag segment 14 , In contrast, two mutually opposed Klemmzahnnachbarn limit a Blechumfangsabschnitt 15 , the single sheet 3 which are on both sides in the circumferential direction 12 subsequent pocket segments 14 spatially separated from each other so that the pocket segments 14 a single sheet 3 are arranged circumferentially in the manner of a common division.

The identical individual sheets 3 are stacked in alternating sequence (ABAB etc.). Every second single sheet is here 3 (A) at an angle α, defined by the width of the pocket bottom 8th in the circumferential direction 12 and the distance of the pocket bottom 8th to the central longitudinal axis 5 is given, against the other intermediate individual sheets 3 (B) twisted. The axis of rotation coincides with the central longitudinal axis 5 together.

Due to the selected stacking sequence (ABAB etc.), the pocket segments are located 14 every other single sheet 3 (A) and serving for the spatial separation sheet metal peripheral sections 15 the other intermediate individual sheets 3 (B) in the stacking direction 11 directly above each other. The same applies to the serving for spatial separation sheet metal peripheral sections 15 every other single sheet 3 (A) and the pocket segments 14 the intervening individual sheets 3 (B). As a result, exactly every second single sheet carries 3 (A) in the laminated core 2 a bag segment 14 for the formation of a receiving bag considered as an example 9 at. Whereas the other intermediate individual sheets 3 (B) one bag segment each 14 for the two in the circumferential direction 12 directly adjacent receiving pockets 9 contribute.

Considering the Klemmzahnanordnung along one of the edges, which separates two side surfaces of the laminated core prism from each other, it turns out that as a result of the alternating stacking the clamping teeth 4 alternately to the adjacent receiving bag 9 to and from the receiving bag 9 are inclined away. Thus, two clamping teeth follow each other along the edge 4 together a swallowtail-like structure.

An enlarged view of a single sheet 3 in the area of a clamping tooth 4 is in the 5 and 9 shown. The clamping tooth 4 is V-shaped with a directly adjacent each pocket segment 14 facing first tooth flank 16 and a corresponding pocket segment 14 remote second tooth flank 17 , One through the two tooth flanks 16 . 17 formed spread angle β is about 25 °. The bag segment 14 facing first tooth flank 16 is about 10 ° against the pocket bottom normals 18 inclined. Thus, that is due to the first tooth flank 16 and the bottom of the bag 8th formed inclination angle γ about 80 °.

The permanent magnets 10 are shaped in the manner of a plano-convex condenser lens and have rounded edges. A permanent magnet already used in this illustration 10 lies positively on the flat bottom of the bag 8th on and in the receiving or clamping pocket 9 one. Its from the bottom of the bag 8th facing away, outwardly facing surface is curved, whereby the rotor 1 the permanent magnets 10 together with the laminated core 2 in the first approximation one by notches 19 Form regularly interrupted cylinder surface.

The profile shows that the linearly extending second tooth flank 17 for a smooth transition between the domed, outwardly facing surface of the permanent magnet 10 and the directly adjacent sheet metal peripheral portion 15 the same single sheet 3 provides.

Between the first tooth flank 16 as well as the immediately adjacent pocket bottom segment area and the permanent magnet 10 is a mirrored L-shaped space 20 leave the positive connection between the permanent magnet 10 and bag segment 14 interrupts. This is filled in the final assembled state of a fastener.

A laminated core 2 from single sheets 3 with alternative Klemmzahngeometrie is in the 10 to 15 shown. If one considers here the clamping tooth arrangement along one of the edges, which separates two side surfaces of the laminated core prism, one recognizes a funnel-shaped or mushroom-like profile. The already used permanent magnets 10 are also in this version form-fitting on the respective flat bottom of the bag 8th on and in the appropriate recording or glassine envelopes 9 one. The space provided for the fastener clearance 20 gives way to the modified clamping teeth 4 from the L-shape and can be considered in the first approximation as sickle-like.

The structure of the laminated core 2 takes place, as well as from the pictures 12 to 15 partially apparent, analogous to the embodiment with V-shaped clamping teeth 4 by stacking identical individual sheets 3 in alternating sequence (ABAB etc.). Again, every second single sheet is 3 (A) by the angle α, which is defined by the width of the pocket bottom 8th in the circumferential direction 12 and the distance of the pocket bottom 8th to the central longitudinal axis 5 is given, against the other intermediate individual sheets 3 (B) twisted. The axis of rotation falls as before with the central longitudinal axis 5 together.

One of these individual sheets 3 with alternative clamping tooth geometry is in 10 and in enlarged detail in FIG 11 shown. Here it can be seen that the subdivision of the individual sheet segments into pocket segments 14 and sheet metal perimeter sections 15 not by means of a clamping tooth inclination, but by means of alternately mirror-inverted shaping of asymmetrical clamping teeth 4 he follows. So you put in the middle between two clamping teeth 4 a perpendicular to the intermediate sheet metal segment extending plane of symmetry, then the two clamping teeth neighbors are mirror-symmetrical to this plane.

The clamping teeth 4 themselves are approximately trapezoidal in shape with a respective adjacent pocket segment 14 facing primary tooth flank 21 and one of the sheet metal peripheral portion 15 facing secondary tooth flank 22 , Connected are the tooth flanks 21 . 22 on the circumference through tooth roofs 23 where each tooth roof 23 together with an imaginary Zahnanformkante on single sheet 3 forms the parallel side pair of the trapezoid. The area where the primary tooth flank 21 on the tooth roof 23 meets, is conspicuously arched, leaving the primary tooth flank 21 has a slight S-shape or mirror-inverted S-shape.

LIST OF REFERENCE NUMBERS

1

rotor

2

laminated core

3

Single sheet

4

securing catch

5

central longitudinal axis

6

admission

7

locking groove

8th

pocket base

9

receiving pocket

10

permanent magnet

11

stacking direction

12

circumferentially

13

face

14

bag segment

15

Sheet peripheral portion

16

first tooth flank

17

second tooth flank

18

Pocket base Normal

19

score

20

free space

21

primary tooth flank

22

secondary tooth flank

23

tooth roof

α

angle

β

splay

γ

Tilt angle Opening angle

ε

clamping profile

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

• DE 10009151 C2 [0004]
• DE 102005044218 A1 [0005]

Claims (15)

Laminated core ( 2 ), in particular for the rotor ( 1 ) of an electric motor, of stacked individual sheets ( 3 ) with a number of pocket segments ( 14 ) in the stacking direction ( 11 ) peripherally open receiving pockets ( 9 ) for permanent magnets ( 10 ), characterized in that - on each individual sheet ( 3 ) an even number of clamping teeth ( 4 ) perpendicular to the stacking direction ( 11 ) is formed, - that each clamping tooth ( 4 ) together with one of its two directly adjacent clamping teeth ( 4 ) a pocket segment ( 14 ) and together with the other directly adjacent clamping tooth ( 4 ) a sheet metal peripheral portion ( 15 ) laterally limited, - that the pocket segments ( 14 ) and the sheet metal peripheral sections ( 15 ) in the circumferential direction ( 12 ) alternately, and - that two in the laminated core ( 2 ) adjacent individual sheets ( 3 ) are rotated relative to each other by an angle α, which by the arc distance between two adjacent clamping teeth ( 4 ) is determined. Laminated core ( 2 ) according to claim 1, characterized in that - each clamping tooth ( 4 ) V-shaped with a respective adjacent pocket segment ( 14 ) facing first tooth flank ( 16 ) and a pocket segment ( 14 ) facing away second tooth flank ( 17 ), - that two in the circumferential direction ( 12 ) adjacent clamping teeth ( 4 ) each in the opposite circumferential direction ( 12 ), and - that two each in the circumferential direction ( 12 ) adjacent and each zugeneiget clamping teeth ( 4 ) a pocket segment ( 14 ) laterally limit. Laminated core ( 2 ) according to claim 2, characterized in that the first and second tooth flanks ( 16 . 17 ) of the clamping tooth ( 4 ) spread angle β greater than 0 ° and preferably less than 25 °. Laminated core ( 2 ) according to claim 2 or 3, characterized in that the inclination angle γ of each clamping tooth ( 4 ) caused by the first tooth flank ( 16 ) and the peripheral, preferably flat, bottom of the bag ( 8th ) is less than 90 ° and preferably greater than 75 °. Laminated core ( 2 ) according to claim 1, characterized in that each clamping tooth ( 4 ) trapezoidal with a respective adjacent pocket segment ( 14 ) facing primary tooth flank ( 21 ) and a sheet metal peripheral portion ( 15 ) facing secondary tooth flank ( 22 ) is trained. Laminated core ( 2 ) according to claim 5, characterized in that by the primary and the secondary tooth flank ( 21 . 22 ) of the clamping tooth ( 4 ) formed opening angle δ smaller than 90 ° and preferably greater than 15 °. Laminated core ( 2 ) according to claim 5 or 6, characterized in that the clamping angle ε, by the primary tooth flank ( 21 ) and the peripheral, preferably flat, bottom of the bag ( 8th ) is less than 90 ° and preferably greater than 75 °. Laminated core ( 2 ) according to one of claims 1 to 7, characterized in that each permanent magnet ( 10 ) in the final assembled state form fit in the pocket segments ( 14 ) of the respective receiving bag ( 9 ) is held. Laminated core ( 2 ) according to one of claims 1 to 8, characterized in that at least one recess between each pocket segment ( 14 ) and the corresponding permanent magnet ( 10 ) is provided for forming a magnet-sheet contact surface clearance. Laminated core ( 2 ) according to claim 9, characterized in that on the inner side of the pocket segment in each case a magnetic sheet-contact surface free space in the respective region of the two clamping teeth ( 4 ) of each pocket segment ( 14 ) is provided. Laminated core ( 2 ) according to one of claims 1 to 10, characterized in that a fastening means between each magnet-sheet contact surface pair and in particular in the, if present, magnetic-sheet-contact surfaces-free spaces is introduced. Laminated core ( 2 ) according to one of claims 1 to 11, characterized in that each permanent magnet ( 10 ) is coated with a, preferably produced by painting or powder coating, impact protection shell. Laminated core ( 2 ) according to one of claims 1 to 12, characterized in that the laminated core ( 2 ) is coated with a, preferably produced by painting or powder coating, corrosion protection sheath. Laminated core ( 2 ) according to claim 13 characterized by a material which is used both as a fastening means and for the formation of the impact protection envelope for the permanent magnets ( 10 ) or the corrosion protection cover for the laminated core ( 2 ) serves. Electric motor with a laminated core ( 2 ) according to one of claims 1 to 14.

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