JP2009519695A - Electric machine, in particular motor rotor and method for manufacturing the rotor - Google Patents

Abstract

  The invention relates to a rotor (13) for use in an electric machine with a magnetic return path (5) having at least one stratified iron core (6) having a flake (1), the flake (1) being a substrate (2). ) And at least two positioning elements (4) integrated in one piece on the base body (2). The rotor (13) is provided with at least one permanent magnet (7), and the permanent magnet (7) is provided on one or more slices (1) of the rotor (13). The position is fixed between two position fixing elements (4). The position fixing element (4) has a smaller magnetic permeability than the substrate (2) of the flakes (1). The invention further relates to a method for manufacturing such a rotor (13). In the method according to the invention, in a first step at least one of the position fixing elements (4) is heat-treated until the position fixing element (4) has a permeability of about 1. However, in this case, the magnetic permeability of the substrate (2) of the thin piece (1) cannot be changed. In the second step, the flakes (1) are cooled.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor used in an electric machine, particularly a motor, provided with a magnetic return path, the magnetic return path having at least one laminated iron core having a plurality of thin pieces. About. The invention further relates to a method for manufacturing a rotor.

  A rotor with a magnetic return path is used in brushless DC motors in the prior art. Brushless DC motors often have separate surface magnets, which are attached to a magnetic return path. In most DC motors, magnets are bonded to the outer surface of the magnetic return path. In this case, different magnet shapes are used, for example shells, cuboids or D-shaped magnet shapes, also called “Breadloibe”.

  The magnetic return path of a direct current motor is either integrally formed from steel in one piece, or consists of a laminated iron core having a plurality of laminated metal sheets positioned in an overlapping manner.

  In order to position the magnet in the magnetic return path, an auxiliary adapter made of plastic, for example, is mounted, which positions the magnet during curing of the adhesive. At the end of the curing process, this auxiliary adapter is removed. In another embodiment, a plurality of position fixing elements are incorporated in the magnetic return path of the rotor, and a magnet is fitted or clamped between these position fixing elements. This provides improved positioning of the magnet. However, since these position-fixing elements are in that case also made of conductive steel, a magnetic flux is formed in the rotor to short-circuit the magnetic flux of the permanent magnet. Thereby, the total magnetic flux is reduced, and the torque of the electric machine, particularly the torque of the DC motor, is reduced.

Advantages of the Invention A rotor according to the invention for use in an electrical machine with a magnetic return path, i.e. a lamina, having the features according to claim 1, is integrated in one piece into the body or base and the body or base. And at least one permanent magnet, the permanent magnet being disposed on one or more lamellas of the rotor. A rotor used in an electric machine, characterized in that the position fixing element is fixed in between and the position fixing element has a smaller permeability than that of the main body or base of the flake, has the following advantages. is there. That is, the position fixing element integrated with the thin plate base of the magnetic return path has extremely small magnetic permeability. One permanent magnet is provided between two adjacent position fixing elements, and the permanent magnets are held by position fixing elements provided in one or more slices. The positioning element has a smaller magnetic permeability than the lamina body or substrate. This prevents a short-circuit / stray flux flow path (Kurzschluss-Streuflusspfad) from being formed between two adjacent permanent magnets in the position-fixing element. A magnetic flux cannot be formed in the position fixing element. This increases the total available magnetic flux in the rotor and increases the torque of the electric machine.

  In the following claims, advantageous refinements of the invention are described.

  It is advantageous if the flakes are made of “Zwei-Zustaende-Material” that can realize two states, a magnetic state (ferromagnetic state) and a non-magnetic state (weak magnetic state). is there. In this case, it is advantageous if a YEP-FA1 material is used. This material makes it possible to achieve ranges with different permeability. This is necessary because the flakes consist of a substrate and a position-fixing element integrated into the substrate in one piece. That is, the flake has a single material. This material must therefore be able to assume different states.

  It is particularly advantageous if the flake material has iron, chromium and carbon as components. In particular, 17.5% by volume of chromium and 0.5% by volume of carbon are used in combination with iron. Such materials are particularly suitable. This is because such a material has a high relative permeability in the magnetic state. It is advantageous if the flakes have a permeability greater than 500, preferably about 900.

  An advantageous material of the flakes has the following magnetic properties in the magnetic state: The magnetic flux density is 1.28 Tesla (T) at a magnetic field strength of 5 kA / m. The coercive force is about 500 A / m. The magnetic properties of the two-state material include a tensile strength of 770 MPa, a stretching stress (proof stress) of 640 MPa, and a hardness of 200 Hv in the magnetic state (ferromagnetic state). The elongation is 15%. In the non-magnetic state (weak magnetic state), the mechanical properties change to a tensile strength of about 930 MPa and a stretching stress (proof strength) of 350 MPa. The hardness remains at 220 Hv. The elongation increases to 40%.

  In a particularly advantageous embodiment, the fixing element provided on the flake is heat treated. Thereby, the magnetic permeability of the position fixing element is reduced. The local heat treatment of the material or flakes results in a significant decrease in the high permeability of the flakes at the heated location. The heat treatment of the flake position-fixing element can be performed sequentially on each flake. In this case, the position-fixing element provided on one slice is heated after the other slice. It is also possible to simultaneously heat all or a plurality of position fixing elements provided in one slice. Of course, in terms of manufacturing technology, a plurality of slices can be heated at the same time, so that the process of “demagnetization” of the fixing element can be promoted. The flake cooling can then take place after all the fixing elements of one flake have been heat-treated, or the fixing elements can be cooled immediately after the heat treatment of the individual fixing elements.

  It is advantageous if the positioning element has a permeability that is less than or equal to 1.01. Thereby, it is advantageous if the magnetic permeability of the position fixing element corresponds to the magnetic permeability of air. That is, the heat treatment allows the two-state material to provide a range where the permeability is less than or equal to 1.01, where another range is a relative permeability in the range of 900. have.

  In yet another advantageous embodiment, the rotor is formed such that a plurality of permanent magnets are arranged on the circumferential surface of the rotor. The permanent magnet is held between two adjacent positioning elements. In this case, it is advantageous if the flakes have a substantially square cross section or a square cross section. A magnet is disposed on the outer surface. Position fixing elements are integrated into the corner (corner corner). Thus, a rotor having a substantially circular cross section can be formed by appropriate selection of permanent magnets, for example, selection of D-shaped permanent magnets.

  In another advantageous embodiment of the invention, an electric machine is formed comprising a rotor according to the invention with a magnetic return path having at least one laminated core with flakes. Such an electric machine, in particular a motor, has the advantage that the permanent magnets arranged on the circumferential surface of the magnetic return path are clamped and clamped between position fixing elements integrated in the lamina. Since no magnetic flux flows between the two adjacent permanent magnets through the laminating, fixed element surrounded by the permanent magnet, the total available magnetic flux of the rotor of the electric machine is increased, thereby increasing the torque of the electric machine. Has been improved. The reason is non-magnetic position fixing elements, and a permanent magnet is arranged between these non-magnetic position fixing elements.

  According to the invention, for producing a rotor having a plurality of flakes comprising a base body and a plurality of positioning elements integrally incorporated in the base body, having the features of claim 10. The method has the advantage that the magnetic permeability of the position fixing element is reduced by heat treatment until the magnetic permeability of the position fixing element corresponds to that of air. As a result, the position fixing element becomes non-magnetic. As a result, the position fixing element has no influence on the magnetic flux formed between the adjacent permanent magnets. For this purpose, according to the method according to the invention, a two-state material is used, from which the flakes are made.

  In the first step, at least one position fixing element of the plurality of position fixing elements of the flake is heat treated. This heat treatment is performed with limited space. The flaky substrate is not heat treated. A known method can be used for the heat treatment of the position fixing element. That is, the position-fixing element can be brought into the furnace and loaded with external thermal radiation or heated by other known means. Since heating is only performed locally, only the magnetic permeability of the fixed element changes. The positioning element is heated until the positioning element has a permeability of about 1. In this case, it must be ensured that the magnetic permeability is less than or equal to 1.01. Thereby, the magnetic permeability of the position fixing element corresponds to the magnetic permeability of air. The permeability of the substrate is not changed during local heat treatment. As a result, the substrate itself has a high magnetic permeability. Subsequently, the flakes or positioning elements are cooled.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, advantageous embodiments of the invention will be described in detail with reference to the drawings.

1 is a schematic diagram showing a rotor flake used in an electric machine;
FIG. 2 is a perspective view showing a rotor composed of a stratified core having a plurality of slices;
3 is a perspective view of the rotor shown in FIG. 2 with a permanent magnet fixed in position;
4 is a cross-sectional view of a motor provided with the rotor shown in FIG. 3;
FIG. 5 is a diagram showing a part of the rotor shown in FIG. 4 having magnetic flux lines.

DESCRIPTION OF EMBODIMENTS Hereinafter, the structure of a motor having a rotor according to the present invention will be described with reference to FIG. FIG. 1 shows a flake 1 with a substantially square substrate 2. A hole 3 is provided at the center of the base 2, and a motor shaft (not shown) extends through the hole 3. The thin piece 1 has a position fixing element 4 at each corner (corner corner), and this position fixing element 4 is connected to the base 2 of the thin piece 1 in one piece, that is, integrally.

  The position fixing element 4 is formed as a spring tongue. The flakes 1 are manufactured in a single work process by punching. The flakes 1 can also be produced by means of laser cutting or other known production methods, with an integrated fixing element 4. Each of the two position fixing elements 4 adjacent to each other are opposed to each other to form a pair. In FIG. 1, the upper position fixing elements 4 and the lower position fixing elements 4 are opposed to each other. The thin piece 1 is made of a “two-state material (Zwei-Zustaende-Material)” that can realize two states of a magnetic state (ferromagnetic state) and a non-magnetic state (weak magnetic state). The substrate 2 is magnetic and has a permeability in the range of 900. The position fixing element 4 is non-magnetic after heat treatment. The magnetic permeability of the position fixing element 4 is in the range of 1.

  FIG. 2 shows the magnetic return path 5 of the rotor 13 composed of two stratified iron cores 6. The laminated iron core 6 of the magnetic return path 5 is composed of a plurality of thin pieces 1 that are stacked on each other. In this case, each of the six thin pieces 1 forms one partial iron core 16. The laminated iron core 6 is assembled from a plurality of partial iron cores 16. In this case, the two partial iron cores 16 are shifted from each other by 90 °. With the rotation angle of 90 °, the shape of the rotor 13 according to the invention shown in FIG. 2 is formed. Based on the fact that the laminated iron core 6 is formed from a plurality of partial iron cores 16 that are each rotated by 90 °, the systematic thickness and shape tolerances of the flakes 1 due to fabrication are compensated.

  FIG. 3 shows a rotor 13 according to the invention with a magnetic return path 5 and a permanent magnet 7 arranged on the outer surface of the lamina 1. The permanent magnet 7 has a D-shaped cross section. That is, the permanent magnet 7 has a “bread loaf” shape. The base surface 8 of the permanent magnet 7 is in contact with the outer surface of the stratified iron core 6. The permanent magnet 7 is fixed between adjacent position fixing elements 4 and cannot be detached from the position. In addition, the permanent magnet 7 can be held on the laminated core 6 by an adhesive. In general, however, it is sufficient to fix the position by means of the position fixing element 4 formed as a spring tongue.

  FIG. 4 shows a cross-sectional view of a motor 9 with a rotor 13 according to the invention. The motor 9 has a stator 10 with six magnetic pole pieces 11. Thus, the 4-pole 3-phase brushless motor 9 can be manufactured. The rotor 13 is disposed in the center of the stator 10. In the cross-sectional view shown in FIG. 4, one thin piece 1 of the rotor 13 is shown. A motor shaft 12 is introduced at the center of the thin piece 1. Four permanent magnets 7 are arranged on the outer surface of the thin piece 1. Each permanent magnet 7 is held by two position fixing elements 4.

  FIG. 5 shows a part of the motor 9 shown in FIG. In this case, two magnetic pole pieces 11 belonging to the stator 10 are shown. The rotor 13 of the motor 9 is rotated so that the position fixing element 4 is positioned between the magnetic pole pieces 11. In the plan view shown in FIG. 5, in addition to the position fixing element 4 of the uppermost thin section 1, the free end portion 14 of the position fixing element 4 of the uppermost thin section 1 of the partial iron core 16 located therebelow is also visible. ing. Both permanent magnets 7, partially illustrated, are in contact with the outer surface of the slice 1. Each permanent magnet 7 is held between two position fixing elements 4.

  In FIG. 5, the magnetic flux in the motor 9 is illustrated by a plurality of lines. Since the position fixing element 4 has a magnetic permeability of about 1 after heat treatment and is nonmagnetic, no magnetic flux lines are formed on the position fixing element 4. The magnetic flux lines extend from the first magnetic pole piece 11 through the permanent magnet 7 through the rotor air gap 15 formed between the rotor 13 and the stator 10. The magnetic flux lines then extend further through the substrate 2 to the adjacent permanent magnet 7 and through the rotor air gap 15 to the next pole piece 11. No short circuit / stray magnetic flux flow path is formed in the position fixing element 4. The motor 9 has an increased torque compared to a conventional motor.

It is the schematic which shows the thin piece of the rotor used for an electric machine. It is a perspective view which shows the rotor which consists of a laminated iron core which has a some thin piece. It is a perspective view which shows the rotor shown in FIG. 2 provided with the permanent magnet by which the position was fixed. It is sectional drawing of the motor provided with the rotor shown in FIG. FIG. 5 is a view showing a part of the rotor shown in FIG. 4 having magnetic flux lines.

Claims (10)

  In a rotor for use in an electric machine with a magnetic return path having at least one laminated iron core (6) with a flake (1), the flake (1) is integrated in one piece with the base (2) and the base (2). At least two position-fixing elements (4) incorporated in the at least one permanent magnet (7), the permanent magnet (7) being one of the rotors (13). Alternatively, the position fixing element (4) is fixed between two position fixing elements (4) provided on the plurality of slices (1), and the position fixing element (4) is smaller than the base (2) of the slice (1). A rotor for use in an electric machine, characterized by having a magnetic susceptibility.   2. The rotor according to claim 1, wherein the flakes (1) are made of a two-state material, preferably a YEP-FA1 material.   The rotor according to claim 2, wherein the material of the flakes (1) comprises iron, chromium and carbon, in particular 17.5% by volume of chromium and 0.5% by volume of carbon.   4. A rotor as claimed in claim 1, wherein the flakes (1) have a magnetic permeability greater than 500, preferably in the range of 900.   The rotor according to any one of claims 1 to 4, wherein the position fixing element (4) provided on the lamina (1) is heat treated to reduce the magnetic permeability of the position fixing element (4). .   6. The rotor according to claim 1, wherein the magnetic permeability of the fixed element (4) is less than or equal to 1.01. 7.   The rotor according to any one of claims 1 to 6, wherein the magnetic permeability of the position fixing element (4) corresponds to the magnetic permeability of air.   The rotor according to any one of claims 1 to 7, wherein a permanent magnet is disposed on a peripheral surface of the rotor (13).   Electric machine comprising a rotor (13) according to any one of the preceding claims. A plurality of laminae (1) comprising a substrate (2) and a plurality of position fixing elements (4) integrally incorporated in the substrate (2), the lamina (1) being a two-state material In a method for manufacturing a rotor consisting of the following steps:
Of the position-fixing elements (4), until the position-fixing element (4) has a permeability of about 1, but the permeability of the substrate (2) of the flakes (1) remains unchanged Heat treating at least one positioning element;
A method for manufacturing a rotor, characterized in that cooling the flakes (1) is carried out.

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