DE102016219973A1 - Electric drive motor - Google Patents

Abstract

The invention relates to an electric drive motor (1), comprising a stator (3) with pole shoes (4) and at least one electrically controllable stator winding (5), and a permanent magnet rotor mounted in the field of the stator winding (5) while leaving an annular gap (6) rotatably drivable (7) comprising a motor shaft (8) and a magnet carrier (9) seated on the motor shaft (8), at which a plurality of separate permanent magnets (10) are distributed over a circumference, each permanent magnet (10) extending radially outwardly facing convex magnetic surface (10a), as well as in the direction of rotation of the permanent magnet rotor (7) facing front end face (10b) and opposite to the direction of rotation of the permanent magnet rotor (7) facing rear end face (10c), and wherein each permanent magnet (10) at its convex Magnetic surface (10 a) both a magnetic south pole (S1), as well as circumferentially offset magnetic north pole (N1) and d The two end faces (10b, 10c) each have one of the south magnetic pole (S2) and the north magnetic pole (N2) as opposite poles of the two magnetic poles (S1, N1) of the convex magnetic surface (10a). The invention also relates to a household appliance with such an electric drive motor (1).

Description

The invention relates to an electric drive motor, comprising a stator with pole pieces and at least one electrically controllable stator winding, and a permanent magnet rotor rotatably mounted in the field of the stator winding while leaving an annular gap, having a motor shaft and a seated on the motor shaft magnetic carrier, to the plurality of separate permanent magnets arranged distributed over a circumference. The invention also relates to a household appliance with such an electric drive motor.

The EP 2 908 407 A2 describes an electric drive motor for a pump, comprising an electrically controllable stator winding and a rotatably mounted in the field of the stator winding while leaving an annular gap rotor having a motor shaft, a seated on the motor shaft magnet carrier and a plurality of at least one outer surface of the magnet carrier distributed permanent magnets arranged, each having at least one outer surface and which are fastened by means of a plastic body produced by encapsulation of the magnetic carrier on the magnetic carrier, wherein the permanent magnets are held on their outer surfaces facing the annular gap by the plastic body such positive and / or non-positively that at least a portion of these outer surfaces exposed.

The object of the invention is to provide an electric drive motor whose permanent magnet rotor is improved.

The object of the invention is achieved by an electric drive motor, comprising a stator with pole shoes and at least one electrically controllable stator winding, and a rotatably mounted in the field of the stator winding while leaving an annular gap permanent magnet rotor having a motor shaft and a seated on the motor shaft magnetic carrier to the plurality of separate permanent magnets are arranged distributed over a circumference, wherein each permanent magnet has a radially outwardly facing convex magnetic surface, and facing in the direction of rotation of the permanent magnet rotor front end side and facing the direction of rotation of the permanent magnet rotor rear end side, and wherein each permanent magnet at its convex Magnetic surface both a magnetic south pole, and offset in the circumferential direction has a magnetic north pole and the two end faces each one of magnetic south pole and magnetic em north pole as opposite poles of the two magnetic poles of the convex magnetic surface.

The electric drive motor may in particular have a fixed outer stator and a rotatably mounted inner rotor. The permanent magnet rotor has a plurality of poles, in particular four, six, eight, ten or twelve poles. Each permanent magnet of the permanent magnet rotor may be arranged separately in the magnet carrier and in particular fixed against slipping and / or falling out. The magnet carrier can be produced, in particular, by inserting the individual permanent magnets and the motor shaft into an injection mold, positioning them in the correct position and encapsulating them with a plastic material, in particular a thermoplastic. The magnetic carrier is formed in such embodiments insofar by the injected and cured plastic compound. The shape of the magnetic carrier is predetermined by the shape of the cavity in the injection mold.

In general, all permanent magnets of the permanent magnet rotor are preferably identical. Each permanent magnet may in particular have a circular-sector-shaped shape. The permanent magnets can be arranged distributed uniformly over the circumference of the permanent magnet rotor. In that regard, the evenly distributed over the circumference of the permanent magnet rotor arranged permanent magnets, apart from minor gaps, to complement a rotating, multi-piece assembled magnet ring. Each permanent magnet considered alone, is preferably formed in one piece. The permanent magnets may in particular be made of hard magnetic ferrites.

Usually, a number of individual permanent magnets corresponding to the number of poles or the number of pole pairs are used on permanent magnet rotors, each permanent magnet having exactly one single north pole and one single south pole. Alternatively, permanent magnet rotors can also have only a single, one-piece annular permanent magnet, which is then magnetized with a number of poles corresponding to the number of poles or the number of pole pairs.

According to the invention, each permanent magnet has at its convex magnetic surface both a magnetic south pole and a magnetic north pole offset in the circumferential direction and the two end faces each have a magnetic south pole and magnetic north pole as opposite poles of the two magnetic poles of the convex magnetic surface, a permanent magnet rotors is provided which manages with a small number of individual permanent magnets, but has a sufficiently high number of poles or pole pairs. In addition, a more expensive to manufacture, difficult to be produced and in use very fragile one-piece ring magnet avoided.

The permanent magnet rotor according to the invention may accordingly comprise a plurality of permanent magnets, each of which has permanent magnets on its convex magnetic surface at least a single magnetic south pole and a single magnetic north pole. In principle, however, each permanent magnet can also have two or more magnetic south poles. Accordingly, each permanent magnet can in principle then also have two or more magnetic north poles. However, each permanent magnet preferably has at its convex magnetic surface exactly one single magnetic south pole and exactly one magnetic north pole. At the magnetic south pole of the convex magnetic surface locally closer to the end face of the permanent magnet, this has a magnetic north pole, which forms the opposite pole to the magnetic south pole of the convex magnetic surface. In the same sense, the permanent magnet on the magnetic north pole of the convex magnetic surface locally closer end face on a magnetic south pole, which forms the opposite pole to the magnetic north pole of the convex magnetic surface.

Each permanent magnet may have a radially inwardly facing concave magnetic surface that is free of magnetic poles.

If each permanent magnet has a radially inwardly facing concave magnet surface and the radially outwardly facing magnet surface is convex, then an annular sector-shaped shape of the permanent magnet is already predetermined. Two, three, four or more individual such permanent magnets can then be put together to form a coaxial with the motor shaft arranged circular ring. In each case one end face of a permanent magnet abuts against another end face of an adjacent permanent magnet. Such adjacent end faces of two adjacent permanent magnets are formed in particular by a pair of a magnetic south pole and a magnetic north pole.

A grouping of a plurality of permanent magnets, for example, in the case of a total of three one-piece permanent magnets carried out in that three permanent magnets, each having a running over 120 degrees arc length, are grouped together to form a 360 degrees running Gesamtkreisring. In the case of a total of four one-piece permanent magnets grouping can be done by four permanent magnets, each having a running over 90 degrees arc length, are grouped together to form a 360 degrees running Gesamtkreisring. In the case of a total of five one-piece permanent magnets, grouping can be carried out by grouping together five permanent magnets, each having an arc length of more than 72 degrees, to form a 360-degree total annulus, etc. It is also possible to slightly deviate from these angular values within the scope of the invention , For example, to deliberately leave a slight gap between the end faces of two adjacent permanent magnets. To leave a gap between the end faces of two adjacent permanent magnets may be useful, for example, to compensate for manufacturing tolerances in the dimensions of the individual permanent magnets or, for example, to have room through the gap, so that the individual permanent magnets can adapt to changes in temperature during operation, without tension in the permanent magnets occur.

The radially outwardly facing convex magnetic surface and the radially inwardly facing concave magnetic surface may each be a circular cylindrical jacket wall of the permanent magnet. The radially outwardly facing convex magnetic surface and the radially inwardly facing concave magnetic surface may be arranged aligned at a distance parallel to each other and thus form annular sector-shaped permanent magnets of constant wall thickness.

Each permanent magnet can be made of a pressed and then sintered magnetic powder which is exposed to a magnetization field during the production of the permanent magnet, in which the emerging from the magnetic north pole on the convex magnetic surface of the permanent magnet to be magnetized and / or in the magnetic south pole at the Convex magnetic surface of the magnetizing permanent magnet entering magnetic field lines each compact in a virtual focus, which lies on a magnetization radius outside the outer contour radius of the convex magnetic surface of the permanent magnet.

If the permanent magnets are produced from a pressed and subsequently sintered magnetic powder, it is particularly expedient if each individual, one-piece permanent magnet has an arc length which runs through less than 180 degrees, that is to say preferably 120 degrees, 90 degrees, 72 degrees or less , This ensures that in a pressing operation at all points of the permanent magnet sufficiently high pressing forces can be introduced into the magnetic powder.

The magnetization radius may be larger by a factor of 1.2 to 1.8 than the outer contour radius of the convex magnetic surface of the permanent magnet. Such a ratio of magnetization radius to outer contour radius causes a particularly favorable course of the magnetic field lines in the permanent magnet.

In a specific embodiment, the permanent magnet rotor may have exactly three permanent magnets, which are distributed on the magnet carrier over the circumference and offset by 120 degrees relative to each other.

In this case, grouping of a plurality of permanent magnets may be performed by grouping together the three permanent magnets, each having an arc length in excess of 120 degrees, to form a 360 ° continuous ring.

Each permanent magnet may be in the shape of a circular ring sector having an axially extending mirror symmetry plane from which the center of the magnetic north pole of the convex magnetic surface is offset by a first angle.

Each permanent magnet may be in the form of a donut cylinder sector having an axially extending mirror symmetry plane from which the center of the south magnetic pole of the convex magnet surface is offset by a second angle.

In the event that grouping of a plurality of permanent magnets is effected by grouping together three permanent magnets, each having an arc length of more than 120 degrees, to form a total circular ring running through 360 degrees, the first angle may be 30 degrees, for example, and the second angle may be 30 degrees Degrees. This causes an evenly circumferential alternating distribution of north poles and south poles across the outer shell of the permanent magnet rotor, at 60 degree intervals.

Accordingly, in a first variant, the first angle and the second angle may have the same angular size in absolute terms, but may run in opposite directions starting from the mirror symmetry plane.

However, in a second variant, the first angle and the second angle may also have different angular sizes in terms of magnitude.

Each permanent magnet may, in all described embodiments, have at its respective convex magnetic surface a groove extending longitudinally in the axial direction.

The longitudinally extending groove in the axial direction can delimit the respective convex magnetic surface of a permanent magnet in two equally sized sub-surfaces. In each case one of the two magnetic poles of the convex magnetic surface can be arranged on each of these two sub-surfaces. The groove extends so far between the two magnetic poles of the convex magnetic surface and separates the one magnetic pole of the convex magnetic surface of the other magnetic pole of the convex magnetic surface.

The longitudinally extending groove in the axial direction may have a different or further function. Thus, the groove may form a channel in which plasticized plastic mass may flow during the manufacture of the magnetic carrier, when the permanent magnet and the motor shaft are inserted into an injection mold to produce the magnetic carrier by injection molding. The permanent magnets and the motor shaft are encapsulated by the plastic compound and the magnetic carrier formed. In the cured state of the plastic mass consequently webs of plastic are formed in the grooves, which mechanically support the permanent magnets against the force acting on the permanent magnets due to the rotation of the permanent magnet rotor centrifugal force during operation of the drive motor and thus hold the permanent magnets on its circumference.

Generally, one or more edges of each permanent magnet may be chamfered.

The chamfers may be present on individual, several or all edges of the respective permanent magnet. Each chamfer may be present on preferably the rectangular edges of the permanent magnet. In particular, each chamfer can be formed by an angular position set at 45 degrees to one of the contact surfaces of the edge. The chamfers can be introduced in particular already during the production of the permanent magnets by pressing and sintering of the magnetic powder. In particular, they need not be subsequently produced by abrading or chamfering the rectangular edges of the permanent magnet.

The object is also achieved by a household appliance, in particular a dishwasher, a washing machine, a dryer, an extractor hood, or a household appliance pump, in particular as a component of one of said domestic appliances, comprising an electric drive motor according to one or more of described and / or illustrated embodiments.

Concrete embodiments of components according to the invention of electric drive motors are explained in more detail in the following description with reference to the accompanying figures. Certain individual features of these embodiments, regardless of the specific context in which they are mentioned, may, if appropriate also individually or in combinations other than those shown, represent general features of the invention.

• 1 eine perspektivische Darstellung einer beispielhaften Haushaltsgerätepumpe einer Geschirrspülmaschine, die einen elektrischen Antriebsmotor aufweist;
• 2 eine Schnittdarstellung der Haushaltsgerätepumpe gemäß 1 und des elektrischen Antriebsmotors;
• 3 eine explodierte Darstellung eines erfindungsgemäßen Permanentmagnetenrotors des elektrischen Antriebsmotors gemäß 2;
• 4 eine perspektivische Darstellung des Permanentmagnetenrotors gemäß 3 in der Zusammenstellung;
• 5 eine schematische Darstellung des Magnetisierungsfeldes zur Herstellung der erfindungsgemäßen Permanentmagnete;
• 6 eine schematische Darstellung der Magnetfeldlinien innerhalb eines erfindungsgemäßen Permanentmagneten;
• 7 eine stirnseitige Draufsicht auf einen erfindungsgemäßen Permanentmagneten;
• 8 eine Ansicht auf die konvexe Magnetoberfläche eines erfindungsgemäßen Permanentmagneten; und
• 9 eine schematische Darstellung eines Querschnitts durch den erfindungsgemäßen elektrischen Antriebsmotor mit drei gleichmäßig über den Umfang verteilt angeordneten erfindungsgemäßen Permanentmagneten und schematisch eingezeichneten Magnetfeldlinien.

Show it:

• 1 a perspective view of an exemplary domestic appliance pump of a dishwasher, which has an electric drive motor;
• 2 a sectional view of the household appliance pump according to 1 and the electric drive motor;
• 3 an exploded view of a permanent magnet rotor according to the invention of the electric drive motor according to 2 ;
• 4 a perspective view of the permanent magnet rotor according to 3 in the compilation;
• 5 a schematic representation of the magnetizing field for producing the permanent magnets according to the invention;
• 6 a schematic representation of the magnetic field lines within a permanent magnet according to the invention;
• 7 a frontal plan view of a permanent magnet according to the invention;
• 8th a view of the convex magnetic surface of a permanent magnet according to the invention; and
• 9 a schematic representation of a cross section through the electric drive motor according to the invention with three uniformly distributed over the circumference arranged according to the invention permanent magnet and schematically drawn magnetic field lines.

The 1 to 9 show components of an exemplary electric drive motor 1 a household appliance pump 2 an exemplary dishwasher, comprising, in particular in 9 shown a stator 3 with pole shoes 4 and at least one electrically controllable stator winding 5 , and one in the field of the stator winding 5 leaving an annular gap 6 rotatably driven mounted permanent magnet rotor 7 ,

The permanent magnet rotor 7 points, in particular in 3 in an exploded view and in 4 shown in the assembly, a motor shaft 8th and one on the motor shaft 8th sitting magnetic carrier 9 on, at which several separate permanent magnets 10 arranged distributed over a circumference.

Every permanent magnet 10 has according to the invention, in particular in 6 is shown, a radially outwardly facing convex magnetic surface 10a , as well as in the direction of rotation of the permanent magnet rotor 7 facing front end 10b and a counter to the direction of rotation of the permanent magnet rotor 7endeende end face 10c on, with each permanent magnet 10 at its convex magnetic surface 10a both a magnetic south pole S1, and offset in the circumferential direction has a magnetic north pole N1 and the two end faces 10b . 10c one each of magnetic south pole S2 and north magnetic pole N2 as opposite poles of the two magnetic poles S1 and N1 of the convex magnetic surface 10a exhibit.

Every permanent magnet 10 is made of a pressed and then sintered magnetic powder produced during the manufacture of the permanent magnet 10 is exposed to a magnetizing field, as in 5 schematically shown, in which the magnetic north pole N1 at the convex magnetic surface 10a of the permanent magnet to be magnetized 10 emerging and / or in the magnetic south pole S1 at the convex magnetic surface 10a of the permanent magnet to be magnetized 10 entering magnetic field lines each in a virtual focus F1 . F2 compact on a magnetizing radius R outside the outer contour radius r the convex magnetic surface 10a of the permanent magnet 10 lies.

Every permanent magnet 10 has in the case of the present embodiment, a radially inwardly facing concave magnetic surface 10d on, which is free of magnetic poles.

The magnetization radius R may, as in the case of the present embodiment, be larger by a factor of 1.2 to 1.8 than the outer contour radius r the convex magnetic surface 10a of the permanent magnet 7 ,

The permanent magnet rotor 7 has in the case of the present embodiment exactly three permanent magnets 10 on, attached to the magnet carrier 9 Distributed over the circumference by 120 degrees offset from each other, as in particular in 9 is shown.

As in particular in 6 and 7 is shown, each permanent magnet has 10 the shape of a circular ring sector having an axially extending mirror symmetry plane S from which the center of the north magnetic pole N1 of the convex magnetic surface 10a is arranged offset by a first angle α. In addition, the center of the south magnetic pole S1 is also the convex magnetic surface 10a from the axially extending mirror symmetry plane S starting offset by a second angle β.

In this embodiment of the 6 and 7 points each permanent magnet 10 at its convex magnetic surface 10a exactly one magnetic south pole S1 and exactly one magnetic north pole N1. At the magnetic south pole S1 of the convex magnetic surface 10a locally closer to the front 10b of the permanent magnet 10 this has a magnetic north pole N2, which is the opposite pole to the magnetic south pole S1 of the convex magnetic surface 10a forms. In the same sense, the permanent magnet 10 at the magnetic north pole N1 of the convex magnetic surface 10a locally closer to the front 10c a magnetic south pole S2, which is the opposite pole to the magnetic north pole N1 of the convex magnetic surface 10a forms.

In this exemplary and generally preferred embodiment, the first angle α and the second angle β have the same angular magnitude, starting from the mirror symmetry plane. However, the two angles α and β angle run in opposite directions.

The 6 and the 7 In addition, as in the case of the present embodiment, each permanent magnet 10 at its respective convex magnetic surface 10a a longitudinally extending groove in the axial direction 11 having.

In addition, as in 7 and 8th shown the edges of each permanent magnet 10 provided with chamfers 12.

The 9 shows a grouping of several permanent magnets 10 using the example of a total of three integral permanent magnets 10 , The three permanent magnets 10 each have a more than 120 degrees arc length and are grouped together to form a 360 degrees running Gesamtkreisring. From these angle values can also be deviated slightly within the scope of the invention, for example, to between the end faces 10b . 10c two adjacent permanent magnets 10 deliberately leave a slight gap. A gap between the front sides 10b , 10c of two adjacent permanent magnets 10 it may be useful to keep in mind, for example, manufacturing tolerances in the dimensions of the individual permanent magnets 10 To be able to balance or, for example, to have room through the gap, so that the individual permanent magnets 10 can adapt to changes in temperature during operation without tension in the permanent magnets 10 occur.

The radially outwardly facing convex magnetic surfaces 10a and the radially inwardly facing concave magnetic surfaces 10d form in the case of the illustrated embodiment, in each case a circular cylindrical jacket wall of the permanent magnet 10 , The radially outwardly facing convex magnetic surface 10a and the radially inwardly facing concave magnetic surface 10d can be arranged as shown at a distance aligned parallel to each other and thus circular sector-shaped permanent magnets 10 form constant wall thickness.

LIST OF REFERENCE NUMBERS

1

electric drive motor

2

Appliances pump

3

stator

4

pole pieces

5

stator

6

annular gap

7

Permanent magnet rotor

8th

motor shaft

9

magnet carrier

10

permanent magnets

10a

convex magnetic surface

10b

front end

10c

rear end face

10d

concave magnetic surface

11

groove

F1, F2

focus

R

magnetization radius

r

Outer contour radius

S

Mirror symmetry plane

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 2908407 A2

Claims (12)

Electric drive motor, comprising a stator (3) with pole shoes (4) and at least one electrically controllable stator winding (5), and a permanent magnet rotor (7) which is rotatably mounted in the field of the stator winding (5) while leaving an annular gap (6), which motor shaft (8) and a magnet carrier (9) which is seated on the motor shaft (8) and on which a plurality of separate permanent magnets (10) are distributed over a circumference, characterized in that each permanent magnet (10) has a convex magnet surface (FIG. 10a) and a front end face (10b) pointing in the direction of rotation of the permanent magnet rotor (7) and a rear end face (10c) pointing counter to the direction of rotation of the permanent magnet rotor (7), each permanent magnet (10) both on its convex magnet surface (10a) a magnetic south pole (S1), as well as circumferentially offset magnetic north pole (N1) and the two Sti Each side (10b, 10c) has one of the south magnetic pole (S2) and the north magnetic pole (N2) as opposite poles of the two magnetic poles (S1, N1) of the convex magnetic surface (10a). Electric drive motor behind Claim 1 , characterized in that each permanent magnet (10) has a radially inwardly facing concave magnetic surface (10d) which is free of magnetic poles. Electric drive motor behind Claim 1 or 2 , characterized in that each permanent magnet (10) is made of a pressed and subsequently sintered magnetic powder exposed during the manufacture of the permanent magnet (10) to a magnetizing field in which the magnetic north pole on the convex magnetic surface (10a) of magnetizing permanent magnet (10) emerging and / or entering the magnetic south pole on the convex magnetic surface (10a) of the permanent magnet to be magnetized (10) magnetic field lines each in a virtual focus (F1, F2) compressing on a magnetization radius (R) outside the outer contour radius (r) of the convex magnetic surface (10a) of the permanent magnet (10). Electric drive motor behind Claim 3 , characterized in that the magnetization radius (R) is greater by a factor of 1.2 to 1.8 than the outer contour radius (r) of the convex magnetic surface (10a) of the permanent magnet (10). Electric drive motor after one of Claims 1 to 4 , characterized in that the permanent magnet rotor (7) has exactly three permanent magnets (10) which are distributed on the magnetic carrier (9) distributed over the circumference by 120 degrees to each other. Electric drive motor behind Claim 5 characterized in that each permanent magnet (10) is in the form of a circular cylinder sector having an axially extending mirror symmetry plane (S) from which the center of the magnetic north pole of the convex magnetic surface (10a) is offset by a first angle (a) is. Electric drive motor behind Claim 6 characterized in that each permanent magnet is in the form of a circular cylinder sector having an axially extending mirror symmetry plane (S) from which the center of the South magnetic pole of the convex magnetic surface (10a) is offset by a second angle (β). Electric drive motor behind Claim 7 , characterized in that the first angle (a) and the second angle (β) in terms of magnitude have the same angular size, starting from the mirror symmetry plane (S), however, run in opposite directions. Electric drive motor behind Claim 7 , characterized in that the first angle (a) and the second angle (β) in terms of magnitude have different angular sizes. Electric drive motor after one of Claims 1 to 9 , characterized in that each permanent magnet (10) on its respective convex magnetic surface (10a) has a longitudinally extending groove in the axial direction (11). Electric drive motor after one of Claims 1 to 10 , characterized in that one or more edges of each permanent magnet (10) is provided with a chamfer (12). Domestic appliance, in particular dishwasher, washing machine, dryer extractor hood or household appliance pump (2), comprising an electric drive motor (1) according to one of Claims 1 to 11 ,

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