DE102019200767A1 - Permanent magnet rotor - Google Patents

Abstract

The invention relates to a permanent magnet rotor (1) consisting of a permanent magnet (2), a magnetically conductive area (3) and a shaft (4). The object of the invention is to provide for a generic permanent magnet rotor for sufficient strength of the connection between a permanent magnet and a yoke material and for a high magnetic efficiency in economical production. This object is achieved according to the invention by the features of device claim 1 and method claims 13 and 14.

Description

The invention relates to a permanent magnet rotor ( 1 ), consisting of a permanent magnet ( 2nd ), a magnetically conductive area ( 3rd ) and a wave ( 4th ).

Permanent magnets for permanent magnet rotors can consist of a single permanent magnet ring or of several discrete permanent magnets which are mounted on a carrier. For this purpose, a number of fastening options are known and in use. One way to attach permanent magnets is by gluing. However, gluing is hardly suitable for some areas of application because the adhesive can lose its holding power due to environmental influences or aggressive media to which the adhesive is exposed. Another possibility is to inject the permanent magnets with plastic and thereby hold them in place. When injecting with a plastic material, a magnetic ring with a larger ring thickness is usually used in order to be able to provide it with a multipolar lateral magnetization. Thinner magnetic rings are therefore often used for economic reasons. In this case, a yoke ring on the inside of the magnetic ring is required to achieve sufficient efficiencies.

The object of the invention is to provide for a generic permanent magnet rotor for sufficient strength of the connection between a permanent magnet and a yoke material and for a high magnetic efficiency in economical production.

This object is achieved according to the invention by the features of device claim 1 and method claims 13 and 14. Based on the fact that the magnetically conductive area ( 3rd ) is a plastic filled with magnetically conductive particles, the above object can be achieved. As a result, an injection molding process can be used to fasten the permanent magnets without creating magnetically insulating areas.

It is preferred to use iron powder as a magnetically conductive particle, because it is economical to produce, always available and magnetically highly effective.

Magnetic field lines are usually distributed unevenly within a magnetic circuit, so it is not necessary to provide the same density of magnetic particles at all points in the magnetically conductive area. Rather, a high density of magnetic particles should also prevail in places of high flux density.

In order to achieve high mechanical strength, it makes sense that the permanent magnet ( 2nd ) and the magnetically conductive area ( 3rd ) are positively connected.

Even the wave ( 4th ) can be used with the magnetically conductive area ( 3rd ) be positively connected.

The permanent magnet ( 2nd ) can be designed as a ring magnet. This geometry allows a high strength of the permanent magnet rotor.

In order to save permanent magnet material, it is provided that the permanent magnet ( 2nd ) on the inside radially outward recesses ( 7 ) into which the magnetically conductive area ( 3rd ) extends.

Ring magnets are often multipolar laterally magnetized. Depending on the thickness of the permanent magnet ring, the magnetic field lines within the permanent magnet ring occur more or less strongly in the magnetically conductive area ( 3rd ) and lead from there to the neighboring pole and emerge from the pole surface in the air gap.

As already mentioned, the concentration of the magnetically conductive particles can be distributed unevenly. The concentration of the magnetically conductive particles in the vicinity of the permanent magnet ( 2nd ) is higher than in areas close to the shaft.

The concentration of the magnetically conductive particles is generally greatest along magnetic field lines of the permanent magnet.

In order to save magnetically conductive particles, the permanent magnet rotor can be designed so that between the shaft ( 4th ) and the magnetically conductive area ( 3rd ) an annular hub ( 5 ) is arranged without magnetically conductive particles.

• - Bereitstellung eines vormagnetisierten Permanentmagneten (2) und einer Welle (4);
• - Einführen des Permanentmagneten (2) und der Welle (4) in eine Spritzgussmaschine;
• - Umspritzen des Permanentmagneten (2) und der Welle mit einem mit Eisenpulver (5) gefüllten Kunststoffmaterial, wobei sich das Eisenpulver entlang der Magnetfeldlinien des vormagnetisierten Permanentmagneten (23) ausrichtet und konzentriert;
• - Entnahme des Permanentmagnetrotors (1) aus der Spritzgussmaschine.

The invention is also achieved by a method for producing a permanent magnet rotor ( 1 ) consisting of a permanent magnet ( 2nd ), a magnetically conductive area ( 3rd ) and a wave ( 4th ) solved, the magnetically conductive area ( 3rd ) one with iron powder ( 5 ) is filled plastic, this process being characterized by the following process steps:

• - Provision of a pre-magnetized permanent magnet ( 2nd ) and a wave ( 4th );
• - insertion of the permanent magnet ( 2nd ) and the wave ( 4th ) in an injection molding machine;
• - encapsulation of the permanent magnet ( 2nd ) and the shaft with one with iron powder ( 5 ) filled plastic material, the iron powder along the magnetic field lines of the pre-magnetized permanent magnets ( 23 ) aligns and focuses;
• - Removal of the permanent magnet rotor ( 1 ) from the injection molding machine.

• - Bereitstellung eines vormagnetisierten oder unmagnetisierten Permanentmagneten (2) und einer Welle (4);
• - Einführen des Permanentmagneten (2) und der Welle (4) in eine Spritzgussmaschine;
• - Einspritzen eines mit magnetisch leitenden Partikeln gefüllten Kunststoffmaterials zwischen der Welle und dem Permanentmagneten (2) und
• - Aufmagnetisieren des Permanentmagneten (2) während des Einspritzvorgangs;
• - Entnahme des Permanentmagnetrotors (1) aus der Spritzgussmaschine.

The invention is also achieved by a method for producing a permanent magnet rotor ( 1 ) consisting of a permanent magnet ( 2nd ), a magnetically conductive area ( 3rd ) and a wave ( 4th ) solved, the magnetically conductive area ( 3rd ) one with iron powder ( 5 ) is filled plastic, this process being characterized by the following process steps:

• - Provision of a premagnetized or unmagnetized permanent magnet ( 2nd ) and a wave ( 4th );
• - insertion of the permanent magnet ( 2nd ) and the wave ( 4th ) in an injection molding machine;
• - Injecting a plastic material filled with magnetically conductive particles between the shaft and the permanent magnet ( 2nd ) and
• - Magnetizing the permanent magnet ( 2nd ) during the injection process;
• - Removal of the permanent magnet rotor ( 1 ) from the injection molding machine.

• 1 eine Querschnittdarstellung eines Permanentmagnetrotors,
• 2 eine Längsschnittdarstellung des Permanentmagnetrotors,
• 3 eine erste Variante des Permanentmagnetrotors,
• 4 eine zweite Variante des Permanentmagnetrotors und
• 5 eine dritte Variante des Permanentmagnetrotors.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

• 1 2 shows a cross-sectional illustration of a permanent magnet rotor,
• 2nd 2 shows a longitudinal sectional view of the permanent magnet rotor,
• 3rd a first variant of the permanent magnet rotor,
• 4th a second variant of the permanent magnet rotor and
• 5 a third variant of the permanent magnet rotor.

Note: Reference symbols with an index and corresponding reference symbols without an index denote details of the same name in the drawings and the description of the drawing. This is the use in another embodiment, the prior art and / or the detail is a variant. For the sake of simplicity, the claims, the introduction to the description, the list of reference symbols and the summary contain only reference symbols without an index.

1 shows a cross-sectional view of a permanent magnet rotor 1a according to a first embodiment, with a permanent magnet ring 2a , a magnetically conductive area 3a and a wave 4a . The thickness of the permanent magnet ring 2a is too small for most of the magnetic field lines within the permanent magnet ring 2a close, therefore the magnetically conductive area 3a required to achieve sufficient magnetic efficiency. In this case, the magnetically conductive area is a plastic material which is filled with magnetically conductive particles. In this embodiment, a magnetized permanent magnet ring was used, which together with the shaft 4a was joined with the magnetically conductive material in an injection molding machine. In the plastic state, the magnetically conductive particles could align themselves with the magnetic field and preferentially accumulate in the areas of the highest field line density and thus a compression area 6a form. After the plastic material had hardened, the accumulations of the magnetically conductive particles remained.

2nd shows a longitudinal sectional view of the permanent magnet rotor 1a out 1 , with the wave 4a , the magnetically conductive area 3a , the permanent magnet ring 2a and the compression area 6a . Arrows in the magnetically conductive area 3a are intended to indicate the direction in which the magnetically conductive particles move during the injection molding process.

3rd shows a first variant of the permanent magnet rotor 1b , with a permanent magnet ring 2 B , a wave 4b , a magnetically conductive area 3b and compression areas 6b . The permanent magnet ring 2 B has several, corresponding to the number of poles radially from the inside in the permanent magnet ring 2 B directed returns 7b on. The returns 7b serve to save magnetic material. This magnetic material is replaced by the magnetically conductive area 3b , which fills the corresponding cavities during the injection process.

4th shows a second variant of the permanent magnet rotor 1c , with a permanent magnet ring 2c , a wave 4c and a magnetically conductive area 3c . In this embodiment, the permanent magnet is not yet magnetized during the injection process, so the magnetically conductive particles are aligned 8c not from a magnetic field.

5 shows a second variant of the permanent magnet rotor 1d , with a permanent magnet ring 2d , a wave 4d , a magnetically conductive area 3d and a hub 5d , which consists of a plastic material without magnetic particles. In this embodiment, too, the permanent magnet is not yet magnetized during the injection process, so the magnetically conductive particles are not aligned with a magnetic field. The distance from the permanent magnet ring 2d to the wave 4d is relatively large, so the inner magnetically conductive area 3d is hardly involved in the magnetic circuit, so that the magnetically conductive particles in this area could be dispensed with. The hub 5d therefore serves to save filling material.

Reference list

1

Permanent magnet rotor

2nd

Permanent magnet

3rd

magnetically conductive area

4th

wave

5

hub

6

Compression range

7

Return

8th

Particles

9

Narrowing

10th

Holding means

Claims (14)

Permanent magnet rotor (1), consisting of a permanent magnet (2), a magnetically conductive area (3) and a shaft (4), characterized in that the magnetically conductive area (3) is a plastic filled with magnetically conductive particles. Permanent magnet rotor after Claim 1 , characterized in that the magnetically conductive particles consist of an iron powder. Permanent magnet rotor after Claim 1 or 2nd , characterized in that the magnetically conductive particles in the magnetically conductive region (3) is distributed unevenly. Permanent magnet rotor after Claim 1 , 2nd or 3rd , characterized in that the permanent magnet (2) and the magnetically conductive region (3) are positively connected to one another. Permanent magnet rotor after Claim 1 , 2nd , 3rd or 4th , characterized in that the shaft (4) and the magnetically conductive region (3) are positively connected to one another. Permanent magnet rotor after Claim 1 , 2nd , 3rd , 4th or 5 , characterized in that the permanent magnet (2) is a ring magnet. Permanent magnet rotor after Claim 6 , characterized in that the permanent magnet (2) has on its inside radially outward recesses (7) into which the magnetically conductive region (3) extends. Permanent magnet rotor after Claim 6 or 7 , characterized in that the permanent magnet (2) has a multipolar lateral magnetization. Permanent magnet rotor according to at least one of the preceding claims, characterized in that the concentration of the magnetically conductive particles in the vicinity of the permanent magnet (2) is higher than in areas close to the shaft. Permanent magnet rotor after Claim 9 , characterized in that the concentration of the magnetically conductive particles is highest in the area of high magnetic field line density. Permanent magnet rotor according to at least one of the preceding claims, characterized in that an annular hub (5) without magnetically conductive particles is arranged between the shaft (4) and the magnetically conductive region (3). Permanent magnet rotor according to at least one of the preceding claims, characterized in that the magnetically conductive particles are highly concentrated in the area between different permanent magnets (2) and are minimally concentrated in the area between the shaft (4) and the permanent magnets (2). Method for producing a permanent magnet rotor (1) consisting of a permanent magnet (2), a magnetically conductive area (3) and a shaft (4), the magnetically conductive area (3) being a plastic filled with iron powder (5), characterized by the following process steps: - provision of a premagnetized permanent magnet (2) and a shaft (4); - Introducing the permanent magnet (2) and the shaft (4) into an injection molding machine; - Injection molding of the permanent magnet (2) and the shaft with a plastic material filled with iron powder (5), the iron powder aligning and concentrating along the magnetic field lines of the premagnetized permanent magnet (23); - Removal of the permanent magnet rotor (1) from the injection molding machine. Method for producing a permanent magnet rotor (1) consisting of a permanent magnet (2), a magnetically conductive area (3) and a shaft (4), the magnetically conductive area (3) being a plastic filled with iron powder (5), characterized by following process steps: - Provision of a premagnetized or unmagnetized permanent magnet (2) and a shaft (4); - Introducing the permanent magnet (2) and the shaft (4) into an injection molding machine; - Injecting a plastic material filled with magnetically conductive particles between the shaft and the permanent magnet (2) and magnetizing the permanent magnet (2) during the injection process; - Removing the permanent magnet rotor (1) from the injection molding machine.

Images