Material layer for high rotational speeds

Abstract

In a method for producing a material layer for a rotor of a dynamoelectric rotary machine, a first suspension with binding agent and solid particles is applied through a first screen onto a base to form a first green body, thereby reproducing a first region of a first material with a first degree of strength. A second suspension with binding agent and solid particles is applied through a second screen onto a base to form an annular second green body concentrically to a layer center, thereby reproducing a second region of a second material with a second degree of strength being higher than the first degree of strength. The first and second green bodies are joined such as to form a material recess substantially at a layer center. A permanent material bond of the first and second green bodies and the solid particles is created by heating and/or by compression.

Claims

1. A method for producing a material layer for a rotor of a dynamoelectric rotary machine with a rotational direction about a rotational axis arranged in a layer center of the material layer, wherein the material layer has a material recess arranged substantially at the layer center, wherein the material layer has a first region, wherein the first region has a first material with a first degree of strength, wherein the material layer has a substantially annular second region arranged concentrically to the layer center, wherein the second region has a second material with a second degree of strength higher than the first degree of strength, wherein the first material and the second material are connected with a material bond, wherein the material layer has at least a first region, comprising a first material, and at least a second region comprising a second material, said method comprising: applying a first suspension having a binding agent and solid particles through a first screen onto a base to form a first green body, thereby reproducing from the first screen the first region of a first material with a first degree of strength; applying a second suspension having a binding agent and solid particles through a second screen onto a base to form a second green body, thereby reproducing from the second screen the second region of a second material with a second degree of strength which is higher than the first degree of strength; joining the first green body and the second green body such as to form the material recess substantially at a layer center, with the second region being annular and arranged concentrically to the layer center; creating a permanent material bond of the first and second green bodies and the solid particles by heating and/or by compression, in particular by sintering, wherein the solid particles of the first suspension comprise particles with a first permeability, and the solid particles of the second suspension comprise particles with a second permeability, wherein the second permeability is lower than the first permeability and the second region adjoins the material recess arranged in the layer center and the second region on its outer circumference adjoins an inner circumference of the first region, and the first region on its inner circumference adjoins the outer circumference of the second region; forming at least one third region enclosed by the first region, each said at least one third region comprising a pocket having permanent magnetic material; and applying a baking varnish coating on both of an upper layer side and a lower layer side of the material layer, the material layer capable of being mutually consolidated with a further said material layer by the baking varnish coating of the material layer and the further material layer to form a material layer structure.

2. The method of claim 1, wherein the solid particles comprise metal particles.

3. A material layer for a rotor of a dynamoelectric rotary machine with a rotational direction about a rotational axis arranged in a layer center of the material layer, said material layer comprising: a material recess arranged substantially at the layer center; a first region of a first material with a first degree of strength and a first magnetic permeability; a substantially annular second region connected to the first material with a material bond such as to form the material recess substantially at the layer center, with the second region arranged concentrically to the layer center and having a second material with a second degree of strength which is higher than the first degree of strength and having a second magnetic permeability lower than the first magnetic permeability, wherein the second region adjoins the material recess arranged in the layer center, and the second region on its outer circumference adjoins an inner circumference of the first region, and the first region on its inner circumference adjoins the outer circumference of the second region; at least one third region enclosed by the first region, each said at least one third region comprising a pocket having permanent magnetic material; said material layer having an upper layer side and a lower layer side; and a baking varnish coating on both of the upper layer side and the lower layer side of the material layer capable of being mutually consolidated with a further said material layer by the baking varnish coatings of the material layer and the further material layer to form a material layer structure.

4. The material layer of claim 3, wherein the second material has a tensile strength of at least 800 MPa.

5. The material layer of claim 3, wherein the first magnetic permeability is μr>50, and the second magnetic permeability is μr<5.

6. The material layer of claim 3, wherein the material layer has a thickness of 0.5 to 500 μm.

7. The material layer of claim 3, wherein a transition from the first region to the second region is abrupt.

8. The material layer of claim 3, wherein the permanent magnetic material is connected with a material bond to the first material.

9. The material layer of claim 3, wherein the second material has a tensile strength of at least 1000 MPa.

10. The material layer of claim 3, wherein the at least one third region functions as an internal permanent magnet and forms a pole.

11. The material layer of claim 3, wherein a plurality of third regions are arranged such that the permanent magnetic material forms permanent magnets that are inclined, staggered, or axial parallel with respect to the rotational axis.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention is described and explained below in more detail with reference to the exemplary embodiments depicted in the figures, which show:

(2) FIG. 1 a material layer according to the invention,

(3) FIG. 2 a possible embodiment of the material layer with recesses for internal permanent magnets,

(4) FIG. 3 a possible embodiment of the material layer with insulation material,

(5) FIG. 4 a possible embodiment of the material layer with permanent magnetic material,

(6) FIG. 5 a possible embodiment of a material layer structure,

(7) FIG. 6 a method for producing a material layer,

(8) FIG. 7 a method for producing a material layer structure, and

(9) FIG. 8 the dynamoelectric rotary machine 21.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(10) FIG. 1 shows a material layer 1 according to the invention.

(11) The material layer 1 has a material recess 5 arranged substantially at the layer center. The material layer 1 has a first region 3. The first region 3 has a first material with a first degree of strength.

(12) The first material is for example pure iron, in particular pure iron with <0.01% carbon.

(13) In the figure, the material layer 1 has an annular second region 2 arranged concentrically to the layer center M. The second region 2 has a second material with a second degree of strength higher than the first degree of strength. In the figure, an outer circumference of the second region adjoins an inner circumference of the first region.

(14) The second material is, for example, a steel, in particular with the material number 1.8161.

(15) The first material and the second material are connected with a material bond.

(16) In this way, in the figure, the first region 3 and the second region 2 are also connected with a material bond.

(17) The figure shows that the first region 3 is arranged concentrically to the layer center M. In the figure, an outline of an outer circumference A of the material layer 1 is round.

(18) However, it is also possible for the outline of the outer circumference A of the material layer 1 to be not round.

(19) For example, a material layer for a flower rotor has a flower-like outer circumference. The flower rotor is a rotor particularly for permanently excited synchronous machines. The permanent magnets are embodied as magnets of constant height with an enlarged air gap at the edge, Herein, an inner radius of the permanent magnets, which are preferably embodied as shell-type magnets, is preferably equal to an outer radius. The flower rotor achieves a reduction in torque ripple and togging torque.

(20) Other outlines are also possible.

(21) In the figure, the second region 2 defines an inner circumference I of the material layer 1. In the figure, the second region 2 adjoins the material recess 5 arranged in the layer center M.

(22) The reference characters described also apply to the following figures when used in the exemplary embodiments and will not be explained again for reasons of clarity,

(23) FIG. 2 shows a possible embodiment of the material layer 1 with recesses 10 for internal permanent magnets.

(24) If a plurality of material layers 1 are arranged one on top of another, the recesses 10 in the material layer structure form pockets (in other words: openings), Permanent magnets can be inserted into these pockets.

(25) The recesses 10 in each case have an outline adapted to match an outline of permanent magnets for insertion, in particular subsequently.

(26) Preferably, the outline is adapted such that the material layer 1 or material layer structure and permanent magnet are connected in a force-filling manner.

(27) FIG. 3 shows a possible embodiment of the material layer 1 with insulation material.

(28) The material layer 1 has a layer thickness d. Each material layer 1 preferably has an insulation material on at least one layer side. The figure shows an embodiment according to which each material layer 1 has an insulation material 7, 8 on both layer sides. In the figure, the insulation material is varnish, in particular baking varnish. This corresponds to a preferred embodiment.

(29) The insulation material and the material layer are preferably connected with a material bond. The material layer 1 is preferably in one piece.

(30) The material layer 1 has varnish 7 with an insulation thickness d7 on an upper layer side and varnish 8 with an insulation thickness d8 on a lower layer side.

(31) It is also possible for the material layer 1 to have a different type of insulation material and varnish in addition. It is also possible for the material layer 1 to have a different type of insulation material on one layer side and varnish on the other layer side. It is also possible for the material layer 1 to have a mixed form of a different type of insulation material and varnish.

(32) The figure moreover shows a centrally arranged material recess 5 (for later attachment to a shaft, see FIG. 8). A rotational axis R passes through a center point of the material recess 5.

(33) FIG. 4 shows a possible embodiment of the material layer 1 with permanent magnetic material 15.

(34) The material layer 1 has at least one third region 15. The third region has permanent magnetic material. In the figure, the permanent magnetic material is connected with a material bond to the first material.

(35) It is also possible for the permanent magnetic material to be connected to the second material or to the second and first material.

(36) The figure shows six third regions 15 which are used to form poles. Herein, the third regions 15 function as internal permanent magnets.

(37) FIG. 5 shows a possible embodiment of a material layer structure 20.

(38) The material layer structure 20 has a plurality of material layers 1 of the embodiment described in FIG. 4. In the figure, the material layers 1 are arranged along the rotational axis R.

(39) The material layer structure 20 is preferably embodied as a rotor stack. Herein, the rotor stack is a stack comprising a plurality of substantially flat material layers, wherein the material layers touch one another. The material layers are preferably consolidated with one another.

(40) However, the material layer structure 20 is also possible with a plurality of material layers of the embodiments described in FIG. 1, FIG. 2 and/or FIG. 3.

(41) In the figure, the plurality of material layers 1 are also arranged such that the third regions 15 form an inclined permanent magnet arrangement. This reduces the torque ripple and the cogging torque of a dynamoelectric rotary machine that has such a material layer structure 20.

(42) A staggered or axially parallel permanent magnet arrangement is also possible.

(43) FIG. 6 shows a method for producing a material layer.

(44) The material layer has at least one first region having a first material and at least one second region having a second material.

(45) Therefore, in a method step S1, a first suspension having at least one binding agent and solid particles is applied through a first screen onto a base in order to obtain a first green body. The first region is reproduced by the first screen (for example the above-described first region 3).

(46) Here, applied preferably means: the suspension is applied to the base with a doctor blade.

(47) Then, in a method step S2, a second suspension having at least one binding agent and solid particles is applied through a second screen onto a base in order to obtain a second green body. The second region is reproduced by the second screen.

(48) A method step SX shows that these method steps take place until a desired number of green bodies, and hence regions (for example the above-described third region 15 and/or further possible, but not described regions), are present.

(49) Different procedures can be followed: the respective binding agent can be driven out of the first green body and/or the second (and/or further) green body before the joining in a method step S3 (see method step S21) of the first green body and the second green body (and/or further green bodies) and/or after the joining (see method step S31).

(50) The binding agent is preferably driven out by means of debinding.

(51) In a method step S4, a permanent material bond of the two (or more) green bodies with one another and the solid particles in the respective green body is created by heating and/or by means of compression, in particular by means of sintering.

(52) In a method step S6, an insulation material is applied to the material layer on at least one layer side. The insulation material is preferably a varnish, in particular baking varnish.

(53) Here, applied preferably means: insulation material is applied to the layer side with a doctor blade or the layer side is coated with a coating tool or the layer side is immersed in a vessel containing the insulation material.

(54) The screens can be varied in a simple and inexpensive way. If the requirements for the material layer change, for example if the second region is to be wider in the radial direction, the screens can be modified. There are hardly any tool costs.

(55) FIG. 7 shows a method for producing a material layer structure.

(56) In a method step S11, a plurality of material layers (at least two) are joined. The production of the material layers was described in MG 6. To form the material layer structure, material layers, advantageously having baking varnish, are arranged one on top of the other.

(57) In a method step S12, the material layers are baked together for mutual consolidation.

(58) FIG. 8 shows the dynamoelectric rotary machine 21. The machine 21 has a stator 23 and a rotor 22. The rotor 22 is attached to a shaft 24. The rotor 22 has a material layer structure 20.

(59) For example, the material layer 1 for the rotor 22 has a solid region with 1.8161 and a soft region with pure iron.

(60) An exemplary motor with a motor weight of approximately 60 kg and an efficiency of >95% has, for example, the following data: rotor diameter approximately 100 mm, active length approximately 250 mm, power approximately 300 kW, rotational speed approximately 40000 1/min, torque approximately 72 Nm.