DE102013208179A1 - A machine component for providing a magnetic field and electric machine with a machine component - Google Patents

Abstract

Disclosed is a machine component (8, 10) for providing a magnetic field in an adjacent air gap (12) in an electric motor (2), comprising - a carrier element (13, 32), - a magnetically conductive, oriented towards the air gap (12) Sleeve (9, 34, 48), and - at least two excitation magnetic poles (18; 36; 52) arranged radially between the carrier element (13, 32) and the sleeve (9, 34, 48), which transmit the magnetic field via the sleeve ( 9, 34, 48) into the air gap (12), - the sleeve (9, 34, 48) between the two exciter magnetic poles (18; 36; 52) providing magnetic insulation (24, 26; 38, 40; 54, 56).

Description

Technical area

The invention relates to a machine component for providing a magnetic field and to an electrical machine with a machine component.

State of the art

From the DE 197 37 391 A1 For example, a rotor for an electric motor is known in which the permanent magnets are mechanically held by a sleeve.

The sleeve is arranged radially between the exciter magnetic poles and the air gap, wherein the magnetic field from the exciter magnetic poles must be conducted radially over the sleeve. The sleeve is usually formed of a magnetic material and therefore includes the excitation magnetic poles, which are arranged circumferentially around the sleeve, magnetically short.

It is therefore an object of the invention to provide an improved electrical machine in which the magnetic leakage losses are reduced.

Disclosure of the invention

According to the invention, a machine component for providing a magnetic field according to claim 1 and an electrical machine with a machine component and a method for producing a magnetically conductive sleeve for a machine component according to the independent claims are provided.

Preferred embodiments are specified in the dependent claims.

According to one aspect of the invention, a machine component for providing a magnetic field in an adjacent air gap in an electric machine, a support member, an air gap aligned and magnetically conductive sleeve, and at least two radially disposed between the support member and the sleeve exciter magnetic poles, the enter magnetic field over the sleeve in the air gap, wherein the sleeve between the two carrier magnetic poles is magnetically insulating.

The above machine component may be a rotor or a stator in the electric machine that excite, by means of the exciter magnetic poles, a main magnetic field or a transverse magnetic field in a manner known to those skilled in the art for operating the electrical machine. The air gap is therefore arranged radially between the rotor and the stator and extends in the circumferential direction thereto. The excitation magnetic poles can therefore have either electrical magnetic coils or permanent magnets.

The sleeve of the above machine component can hold the exciter magnetic poles on the stator or rotor. The sleeve is arranged radially between the exciter magnetic poles and the air gap, wherein the magnetic field from the exciter magnetic poles must be conducted radially over the sleeve. Therefore, the sleeve should be formed magnetically conductive.

However, based on this consideration, it is recognized in the above machine component that the magnetically conductive sleeve magnetically short-circuits the excitation magnetic poles circumferentially around the sleeve in the circumferential direction. To avoid this, it is proposed in the context of the above machine component to form the sleeve magnetically insulating between the excitation magnetic poles, or, in other words, to introduce a magnetic separation between the exciter magnetic poles in the sleeve.

In this way, the component radially opposite the above machine component in the electric machine achieves more magnetic flux from the magnetic field, so that the rotor can be driven with more magnetic force with a constant overall magnetic field, resulting in a significant increase with the electric machine achievable torque density and thus leads to a significant increase in its efficiency. In this way, the electric machine is improved.

In one embodiment of the above machine component, the magnetic insulation of the sleeve comprises an axially extending through the sleeve receiving space. In principle, the magnetic separation or insulation could be introduced in any way, for example, by constructing the sleeve in several pieces from magnetically conducting and magnetically insulating sections. In a particularly favorable manner, it allows the receiving space to build the sleeve in one piece, and to introduce the magnetic insulation in retrospect. The one-piece sleeve expands the range of possible manufacturing process for the sleeve, which can now be produced inexpensively and with few clock cycles, for example by pressing, molding or deep drawing.

In a further embodiment of the above machine component, the receiving space is filled with a magnetically insulating material. In this way, the material used for the magnetic insulation with a high magnetic resistance, which introduces an effective magnetic break in the sleeve.

The magnetically insulating material is introduced into the receiving space by melting in one embodiment. The magnetically insulating material is thereby defined its composition so that by a common melting of magnetic flux-conducting material of the sleeve and magnetically insulating material in umschmolzenen area for the entire interval of temperatures that occur during manufacture, standstill or operation of the electrical machine, a austenitic structure that is not, like the sleeve, ferromagnetic.

The magnetically insulating material may have a high content of nickel, manganese and / or copper. The magnetically insulating effect can be increased by an additional content of carbon and / or chromium. The molten area between the sleeve and the magnetically insulating material in the region of the receiving space can have 0 to 35% nickel, 0 to 25% manganese, 0 to 10% copper, 0 to 1% carbon and 0 to 25% chromium. The remainder of the material in the molten area may comprise iron or steel-like accompanying elements.

In a further embodiment, the magnetically insulating material may be applied as a tape, wire, rod material or powder to the sleeve before or during reflow. The energy required for remelting can be introduced by a welding technique, such as laser, plasma or arc welding. The receiving space can only form during the melting process.

In another embodiment of the above machine component, the sleeve is a laminated core that is axially connected by the magnetically insulating material. In particular, by the aforementioned melting in the axial direction can be omitted mechanical connecting elements between the individual sheets of the laminated core, such as punching parcel points.

In a further embodiment of the above machine component, the laminated core is formed as a plate coil. As a result, the laminated core is formed in one piece and does not have to be assembled in a packaging process, whereby errors in the number of sheets to be packaged can be reduced. Furthermore, the sheet metal coil can be manufactured from a manufacturing technology. The entire designed as a laminated core sleeve can thus be produced with less material waste and thus with a higher degree of material utilization.

In a further embodiment of the above machine component, the receiving space is formed as a through-hole through the sleeve. In the receiving space, the magnetically insulating material can be used in the form of pins before the reflow process, whereby the individual sheets are aligned with each other. In this way, in the manufacture of the above machine component, the packaging process, the reflow process, and the alignment process can be combined in a single manufacturing step.

In a further embodiment of the above machine component, the sleeve has at the locations of the exciter magnetic poles on radial projections in which the exciter magnetic poles are received. The radial projections, viewed in the circumferential direction of the machine component, allow material to be dispensed between between the radial projections, thereby making the machine component less expensive and lighter.

In an embodiment of the above machine component, the magnetic isolation in the circumferential direction of the machine component is formed on one side of the radial projections before and / or after the exciting magnetic poles. In this way, leakage of the magnetic flux in the circumferential direction of the machine component is avoided. Rather, the magnetic flux is homogenized and concentrated in the radial direction.

Furthermore, the magnetic insulation may be formed as an austenitic alloy zone.

According to a further aspect of the invention, an electric machine, in particular an electric motor, comprises a stator and a rotor which is rotatably arranged relative to the stator, wherein the stator and / or the rotor are designed as the above machine component.

• – Formen eines magnetisch leitfähigen Grundkörpers für die Hülse; und
• – Ausbilden einer magnetischen Isolation in dem magnetisch leitfähigen Grundkörper, so dass ein magnetischer Fluss durch den magnetisch leitfähigen Grundkörper geschwächt oder unterbunden wird.

According to a further aspect, a method for producing a magnetically conductive sleeve for a machine component for providing a magnetic field in an adjacent air gap in an electrical machine, wherein between a support member and the sleeve, two exciter magnetic poles are arranged, which the magnetic field on the sleeve in enter the air gap, the steps:

• - Forming a magnetically conductive body for the sleeve; and
• - Forming a magnetic insulation in the magnetically conductive base body, so that a magnetic flux is weakened or prevented by the magnetically conductive body.

In a development of the specified method, the magnetic insulation is formed by melting and / or remelting.

In an additional development of the magnetically conductive base body is melted for melting and / or remelting, in particular with a laser, with plasma or with an arc.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a schematic cross-sectional view through an electric motor,

2 a schematic cross-sectional view of a section through a stator of an electric motor;

3 a schematic cross-sectional view of the section through the stator of 2 after melting of an austenite-forming material;

4 a schematic cross-sectional view of the section through the stator of 2 after further melting of an austenite-forming material;

5 a schematic cross-sectional view of a rotor for an electric motor;

6 a schematic cross-sectional view of a rotor with alloying zones introduced for an electric motor; and

7 a perspective view of an embodiment of a rotor, in which the alloy zones extend helically around the rotor.

Description of the embodiments

In the figures, elements of identical or comparable function are provided with the same reference numerals and described only once.

It will open 1 Reference is made to an electric motor 2 as an electric machine in a cross-sectional view transverse to its axis of rotation 4 shows that in 1 runs vertically into the plane of the drawing. The electric motor 2 includes one in a housing 6 of the electric motor 2 rotatably mounted stator 8th and one around the axis of rotation 4 and opposite the stator 8th rotatable rotor 10 , Between the stator 8th and the rotor 10 points the electric motor 2 air gaps 12 on, so that the rotor 10 opposite the stator 8th can rotate without friction.

During operation of the electric motor 2 generate depending on the design of the electric motor 2 the stator 8th and / or the rotor 10 magnetic fields, under whose action the rotor 10 can turn. This forms the stator 8th and the rotor 10 Machine components for providing magnetic fields in the air gaps 12 in the electric motor 2 out. The electric motor 2 Can be used for any drive engineering task both in the field of small engines as well as in the field of large drives. Thus, for example, a use as a drive of a hybrid or electric vehicle, not shown in detail in the figure, in particular an electric scooter into consideration.

It will open 2 Reference is made to a section of the stator 8th of the electric motor 2 in a cross-sectional view transverse to the axis of rotation 4 of the electric motor 2 shows. The stator 8th has a holding cage 9 and a magnetically conductive pole housing 13 which represents a support element. Here is the holding cage 9 as a cylindrical laminated core 9 formed, which may for example be composed of a plurality of laminations. The holding cage 9 indicates the rotor 10 facing inside 14 a number of protrusions 16 on that from the inside 14 towards the axis of rotation 4 are formed radially outwardly extending. In these protrusions 16 are exciter magnetic poles 18 otherwise not shown magnets arranged centrally. The holding cage 9 has the shape of a sleeve, on the inside of which the projections project inwards 16 as pole pieces.

The holding cage 9 To perform as a laminated core is particularly advantageous because the individual laminations of the laminated core together with the laminations of the rotor 10 can be punched out, which can also be performed as a laminated core of laminations usually.

At the two side areas 22 the respective projections 16 in the circumferential direction 20 of the stator 8th viewed through each of these two through holes 24 are guided, which are parallel to the axis of rotation in the axial direction 4 of the electric motor 2 extend.

In these through holes 24 can in the production of the holding cage 9 pencils 26 be used. After inserting the pins 26 can the through holes 24 with the pins picked up in it 26 For example, be heated by laser welding and melted with it. As a result, the molten material of the holding cage forms 9 together with the melted material of the pins 26 a remelting alloy 27 in the area of through holes 24 from, after cooling, the individual above-mentioned laminations of the formed as a laminated core holding cage 9 holds together axially. The resulting remelting alloy 27 in the area of through holes 24 is exemplary in 3 shown. It shows 3 With 27 the area in which the remelt alloy over the original through holes 24 spreads when the pins 26 be melted.

The material of the pens 26 is particularly preferably an austenite former. In this way, the remelting alloy forms 27 on cooling, an austenitic structure is placed in the holding cage 9 in the circumferential direction 20 of the stator 8th considered in the field of remelting alloy 27 introduces an increased magnetic resistance, since the austenitic structure other than a ferritic microstructure acts magnetically insulating. In this way arises at the side areas 22 every projection 16 a magnetic insulation in the form of Umschmelzlegierung 27 that prevents the magnetic field strength 28 from the excitation magnetic pole 18 of the respective projection 16 through the side areas 22 passes through and to exciter magnetic poles 18 other projections 16 over the holding cage 9 can flow. Thus, the magnetic field strength becomes 28 in one area 30 between the page areas 22 concentrated and through the air gaps 12 towards the rotor 10 guided. This will cause a short circuit between different exciter magnetic poles 18 different projections 16 over the stator lamination stack 9 avoided, so that by the exciter magnetic poles 18 trained and by the magnetic field strength 28 described magnetic fields across the air gap 12 and thus the rotor 10 must be closed. Consequently, the stator points 8th comparatively low magnetic losses, which has a positive effect on the efficiency of the electric motor 2 effect.

In 4 an embodiment is shown in which, unlike the stator 8th of the electric motor 2 of the 3 the area of remelting alloy appears as an isolation area 31 across the entire width of the page area 22 the projections 16 extends, ie the side area 22 is thereby formed in its width in the circumferential direction completely with an increased magnetic resistance. This can be achieved by removing the entire page area 22 is melted, so that the previously introduced pins 26 austenite forming material in the side area 22 with the molten material of the holding cage 9 connect. This creates an austenitic structure throughout the insulation area 31 educated. In this way it is prevented that webs of high magnetic conductivity remain around the austenitic region of the remelt alloy.

It will open 5 Reference is made to the rotor 10 of the electric motor 2 including a rotor shaft 32 as a carrier element in a cross-sectional representation transverse to the axis of rotation 4 of the electric motor 2 in an exemplary embodiment. Here is the rotor 10 is formed as an EC (electronically commutated) rotor and includes one in the axial direction along the axis of rotation 4 considered sleeve, which in the present embodiment as a cylindrical plate coil 34 made of a magnetically conductive material. Furthermore, the rotor comprises 10 a likewise cylindrical ring magnet 36 with exciter magnetic poles, coaxial with the plate helix 34 is arranged, wherein the plate coil 34 the ring magnet 36 encloses in the circumferential direction and holds this mechanically together. The sheet spiral 34 , So represents a rotor bandage of helically bent metal strip, in which by the movement of the rotor 10 during operation of the electric motor 2 form in a manner known to those skilled eddy currents, which counteract the magnetic field from the ring magnet and thus known per se eddy current losses in the rotor 10 to care.

At two of the axis of rotation 4 from considered to each other opposite points of the plate coil 34 points the rotor 10 each an axially extending alloy zone 38 and 40 on. The alloy zones 38 and 40 cut through the metal spiral 34 in the circumferential direction of the rotor 10 in two parts 42 and 44 , where the alloy zones 38 . 40 between the exciter magnetic poles of the ring magnet 36 are arranged. Although brings the plate coil 34 between the exciter magnetic poles of the ring magnet 36 a magnetic short circuit, the alloy zones 38 . 40 increase the magnetic resistance through the plate coil 34 between exciter magnetic poles of the ring magnet 36 and thus make the short circuit ineffective, so that the magnetic field from the exciter magnetic poles of the ring magnet 36 only over the air gap 12 and the stator 8th can be closed.

The sheet spiral 34 intended in the present embodiment as a sleeve, the exciter magnetic poles of the ring magnet 36 mechanically hold or stabilize. This requires the two parts 42 and 44 the plate coil 34 at the alloy zones 38 and 40 be held firmly together mechanically. To achieve this, the alloy zones 38 and 40 before heating, for example, in the manner described above again be equipped with an austenite-forming material, so that the alloy zones 38 . 40 After cooling, form an austenitic structure.

To that for the education of the austenitic alloy zones 38 . 40 For example, a welding process can be used to fill with the magnetically insulating material. As part of this welding process, the material of the plate coil in the area of the alloy zones to be formed 38 . 40 equipped with the austenite forming material and melted through the welding process. As part of the subsequent cooling then forms as in the context of 2 an austenitic material in the region of the alloy zones 38 . 40 out, which then on the one hand, the mechanical support of the plate coil 34 On the other hand, however, produces magnetically insulating.

The magnetic isolation through the alloy zones 38 . 40 prevents the magnetic field strength 28 from a magnetic pole of the ring magnet 36 through the alloy zones 38 . 40 and to another magnetic pole of the ring magnet 36 can flow. Thus, the magnetic field strength becomes 28 from the ring magnet 36 through the air gaps 12 led towards the stator.

It will open 6 Reference is made, as another machine component, an alternative rotor 10 of the electric motor 2 in a cross-sectional view transverse to the axis of rotation 4 of the electric motor 2 shows. Here is the rotor 10 designed as a two-pole DC rotor (DC = direct current). The rotor 10 comprises a rotor laminated core composed of rotor laminations 46 with a rotor ring 48 , to which at least two rotor legs 50 connect radially inwards. The rotor legs 50 carry exciter magnetic poles forming excitation coils 52 , Here are the two rotor legs 50 to each other, that these in the direction of the axis of rotation 4 consider a line perpendicular to the axis of rotation 4 lies, form. To these rotor legs 50 around are the above excitation coils 52 angulated. Here are the excitation coils 52 electrically connected to each other in a manner known per se, so that from the excitation coils 52 Add generated magnetic fields when to the excitation coils 52 an excitation current is applied.

The rotor ring 48 stabilizes the rotor legs 50 mechanically as the above sleeve in the context of 2 and 3 , In doing so, however, he closes the magnetic field generated by the exciter magnet coils between the exciter magnet coils 52 short and prevents at least part of the excited magnetic field in the air gap 12 entry. In order to avoid this magnetic short circuit, are in the circumferential direction of the rotor 10 considered on the rotor ring 48 between the rotor legs 50 alloy zones 54 . 56 formed in the rotor ring 48 introduce a magnetic interruption.

These alloy zones 54 . 56 can in the same way as in 5 be prepared, and so not only the magnetic short-ready, but also the mechanical stability of the rotor legs 50 with the excitation magnet coils 52 to ensure.

Magnetic isolation by the magnetically insulating material in the alloy zones 54 . 56 prevents the magnetic field strength 28 from an exciter magnetic pole of the excitation magnet coils 52 through the alloy zones 54 . 56 to another exciter magnetic pole of the excitation magnet coils 52 can flow. Thus, the magnetic field strength becomes 28 from the excitation magnet coils 52 through the air gaps 12 led towards the stator.

As in 7 These alloy zones can be shown 54 . 56 also helical about an axis of rotation 62 of the rotor 10 which causes a noise minimization during operation of the electric motor 2 can cause. Here are in 7 as an alternative, more than two alloy zones 54 . 56 shown.

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 19737391 A1 [0002]

Claims (14)

Machine component ( 8th . 10 ) for providing a magnetic field in an adjacent air gap ( 12 ) in an electric machine ( 2 ), comprising - a carrier element ( 13 . 32 ), - one to the air gap ( 12 ) and magnetically conductive sleeve ( 9 . 34 . 48 ), and - at least two radially between the support element ( 13 . 32 ) and the sleeve ( 9 . 34 . 48 ) arranged exciter magnetic poles ( 18 ; 36 ; 52 ), which covers the magnetic field via the sleeve ( 9 . 34 . 48 ) in the air gap ( 12 ), the sleeve ( 9 . 34 . 48 ) between the two exciter magnetic poles ( 18 ; 36 ; 52 ) with a magnetic isolation ( 24 . 26 ; 38 . 40 ; 54 . 56 ) is trained. Machine component ( 8th . 10 ) according to claim 1, wherein the magnetic isolation ( 24 . 26 ; 38 . 40 ; 54 . 56 ) of the sleeve ( 9 . 34 . 48 ) axially through the sleeve ( 9 . 34 . 48 ) comprises extending receiving space. Machine component ( 8th . 10 ) according to claim 2, wherein the receiving space is filled with a magnetically insulating material. Machine component ( 8th . 10 ) according to claim 3, wherein the sleeve ( 9 . 34 . 48 ) is a laminated core, which is axially connected by the magnetically insulating material. Machine component ( 8th . 10 ) according to claim 4, wherein the laminated core as a coil ( 34 ) is trained. Machine component ( 8th ) according to one of claims 2 to 5, wherein the receiving space as a through hole ( 24 ) through the sleeve ( 9 ) is trained. Machine component ( 8th ) according to any one of the preceding claims, wherein the sleeve ( 9 ) at the locations of the exciter magnetic poles ( 18 ) radial projections ( 16 ), in which the exciter magnetic poles ( 18 ) are included. Machine component ( 8th ) according to claim 7, wherein the magnetic isolation ( 24 . 26 ) in the circumferential direction ( 20 ) of the machine component ( 8th ) looks at one side ( 22 ) of the radial projections ( 16 ) before and / or after the exciter magnetic poles ( 18 ) is trained. Machine component ( 8th ) according to any one of the preceding claims, wherein the magnetic isolation ( 24 . 26 ; 38 . 40 ; 54 . 56 ) is formed as an austenitic alloy zone. Machine component ( 8th . 10 ) according to one of the preceding claims, which is used as a rotor ( 10 ) or as a stator ( 8th ) of the electric machine ( 2 ) is trained. Electric machine ( 2 ) comprising a stator ( 8th ) and one to the stator ( 8th ) rotatably mounted rotor ( 10 ), wherein the stator ( 8th ) and / or the rotor ( 10 ) as a machine component ( 8th . 10 ) are formed according to one of the preceding claims. Method for producing a magnetically conductive sleeve ( 9 . 34 . 48 ) for a machine component ( 8th . 10 ) for providing a magnetic field in an adjacent air gap (US Pat. 12 ) in an electric machine ( 2 ), between a carrier element ( 13 . 32 ) and the sleeve ( 9 . 34 . 48 ) two exciter magnetic poles ( 18 ; 36 ; 52 ) are arranged, which the magnetic field over the sleeve ( 9 . 34 . 48 ) in the air gap ( 12 ), comprising: - forming a magnetically conductive base body for the sleeve ( 9 . 34 . 48 ); and - forming a magnetic insulation ( 24 . 26 ; 38 . 40 ; 54 . 56 ) in the magnetically conductive base body, so that a magnetic flux through the magnetically conductive base body between the exciter magnetic poles ( 18 ; 36 ; 52 ) is weakened or prevented. Method according to claim 12, wherein the magnetic isolation ( 24 . 26 ; 38 . 40 ; 54 . 56 ) is formed by melting and / or remelting, in particular as an austenitic alloy zone. The method of claim 13, wherein the magnetically conductive base body for melting and / or remelting, in particular by means of a laser, a plasma or by means of an arc, is welded.

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