JP2015173560A - Manufacturing method for rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a process needed for suppressing a short circuit flow, inside a core, of a magnetic flux generated by permanent magnets.SOLUTION: A plurality of slots 13 are arrayed around a central axis P, on a soft magnetic material 10 extending along the central axis P. Paired ends 13b of a slot 13 are slot's parts closest to an outer peripheral surface 10a of the soft magnetic material 10 when viewed along the central axis P. Injection of a magnet material 14 into the slot 13 deforms the soft magnetic material 10. The deformation deforms the outer peripheral surface 10a into an outer peripheral surface 10b. The deformation of the surface deteriorates a magnetic characteristic of a bridge 101. A magnetic flux generated from a permanent magnet obtained by magnetizing the magnet material 14 flows through the bridge 101 in a short circuit manner. The deterioration in the magnetic characteristic of the bridge 101 suppresses the short circuit flow of the magnetic flux.

Description

  The present invention relates to a technology for manufacturing a rotor, and more particularly to a technology for manufacturing a rotor used in a so-called radial gap type rotating electrical machine.

  Patent Document 1 introduces a technique for preventing a short circuit of magnetic flux from the N pole to the S pole in a rotor incorporating a magnet. Specifically, a magnet arrangement opening hole in which a magnet is embedded in the rotor core is formed. A gap is formed by a part of the magnet arrangement opening hole. The width of the bridge between the gap and the outer peripheral surface of the rotor core or between the gaps is reduced.

  Further, in Patent Document 1, a nonmagnetic resin or the like can be filled in the outer circumferential side gap or the inner circumferential side gap between the magnet and the magnet arrangement opening hole. Furthermore, a solidified layer is provided in the outer circumferential side gap and the inner circumferential side gap. By forming the solidified layer, compressive stress is applied to the electrical steel sheet forming the core. Thereby, passage of the magnetic flux of a bridge is prevented.

  Patent Documents 2 to 4 are listed as prior art documents related to the present invention. All of these disclose techniques for filling resin magnets in the slits of the rotor core.

JP 2012-75256 A Japanese Patent No. 4726105 JP2013-123303A JP 2013-240207 A

  In Patent Document 1, in addition to magnet embedding, a solidified layer is newly provided in order to apply stress to the bridge, resulting in increased process and complexity.

  Therefore, this application aims at simplifying the process required in order to suppress that the magnetic flux which a permanent magnet generate | occur | produces flows in a short circuit inside a core.

  This invention is a method of manufacturing the rotor (1). The method includes a first step and a second step.

  The rotor is surrounded by a stator (2) as an armature and is provided in the rotating electric machine (3) together with the stator. The rotor faces the stator via a gap (d) in the radial direction with respect to the rotation axis (J) of the rotating electrical machine. The rotor includes a core (11) extending along the rotation axis and a permanent magnet (12) embedded in the core.

  In the first step, the core is obtained by deforming the soft magnetic body (10). The soft magnetic body has outer peripheral surfaces (10a, 10b) and extends along the central axis (P). The soft magnetic body has a plurality of slots (13) arranged around the central axis such that the end (13b) viewed along the central axis is closest to the outer peripheral surface.

  In the first step, a magnet material (14) is injected into the slot to deform the soft magnetic body. By the deformation, the soft magnetic body is deformed at a position between the outer peripheral surface and the end portion, and the magnetic characteristics of the soft magnetic body (101) at the position are deteriorated to obtain the core.

  In the second step, the permanent magnet is obtained by magnetizing the magnet material.

  Desirably, the said edge part exhibits convex shape with respect to the said outer peripheral surface seeing from the said central axis.

  Alternatively, preferably, the first step and the second step are performed in parallel.

  Alternatively, preferably, the rotor (1) has a shaft through hole (15) into which a shaft is fitted. In the first step, the soft magnetic body is held in the shaft through hole (15) of the soft magnetic body (10) corresponding to the shaft through hole.

  The rotor obtained by the method for manufacturing a rotor according to the present invention has its center axis coincident with the rotation axis of the rotating electrical machine, whereby the rotor and the stator constitute the rotating electrical machine. Since the magnetic characteristics of the soft magnetic material at the position between the outer peripheral surface and the end of the slot are deteriorated, the effect of suppressing the magnetic flux generated by the permanent magnet from flowing in a short circuit inside the core is improved. In addition, it is possible to simplify the steps necessary to suppress the magnetic flux generated by the permanent magnet from flowing in a short-circuited manner inside the core.

  Further, when the end portion is convex with respect to the outer peripheral surface, when the soft magnetic body is deformed, the stress applied to the soft magnetic body is widespread at a position between the outer peripheral surface and the end portion. The deterioration of the characteristics is widespread, and the effect of suppressing the magnetic flux from flowing in a short circuit inside the core is improved.

It is sectional drawing which shows the structure of the rotary electric machine concerning this Embodiment. It is sectional drawing of the structure of the conventional rotor. It is sectional drawing explaining the process of manufacturing a rotor. It is sectional drawing explaining the process of manufacturing a rotor. It is sectional drawing explaining the process of manufacturing a rotor. It is sectional drawing which expands and shows the shape of a rotor. It is sectional drawing which shows the other shape of the edge part of a slot. It is sectional drawing which shows the other shape of the edge part of a slot. It is sectional drawing which shows another aspect. It is sectional drawing which shows another aspect. It is sectional drawing which shows another aspect.

  FIG. 1 is a cross-sectional view showing the configuration of the rotating electrical machine 3. The rotating electrical machine 3 includes a rotor 1 and a stator 2, which are shown in a simplified manner.

  The stator 2 is an armature, but the armature winding that the armature normally has and the teeth around which the armature winding is wound are omitted, and are schematically shown as a simple cylindrical shape.

  The rotor 1 includes a core 11 extending along the rotation axis J of the rotating electrical machine 3 and a permanent magnet 12. The permanent magnet 12 is embedded in the core 11. A shaft through hole 15 into which a shaft (not shown) is fitted is opened in the vicinity of the rotation axis J of the core 11.

  The rotor 1 is surrounded by the stator 2. More specifically, the rotor 1 faces the stator 2 via the gap d in the radial direction with respect to the rotation axis J.

  As will be described later, the outer diameter of the rotor 1 viewed from the rotation axis J is not a circle. Therefore, the gap d is not constant in the circumferential direction with respect to the rotation axis J. However, FIG. 1 does not show the details of such fluctuations in the outer diameter of the rotor 1 in order to avoid complication of the drawing. Therefore, details of the fluctuation of the gap d are not shown.

  A cross-sectional view of a conventional rotor configuration is shown in FIG. The cross section is perpendicular to the rotational axis of the rotor.

  The soft magnetic body 10 is provided with a slot 13 in which the permanent magnet 12 is embedded. The soft magnetic body 10 between the end 13 b of the slot 13 and the outer peripheral surface 10 a of the soft magnetic body 10 functions as the bridge 101.

  The bridge 101 connects the soft magnetic bodies 10 closer to the outer peripheral surface 10 a than the adjacent permanent magnets 12. Accordingly, the soft magnetic body 10 is short-circuited between the north pole (in the figure, “N” is circled) and the south pole (in the figure, “S” is circled) of the permanent magnet 12. A flowing magnetic flux (hereinafter referred to as “short-circuit magnetic flux”) passes through the bridge 101.

  In order to suppress the short-circuit magnetic flux, the bridge 101 is a thin portion having a narrow radial width with respect to the rotation axis.

  In this embodiment, in order to further suppress the short-circuit magnetic flux, the bridge 101 is deformed to deteriorate its magnetic characteristics.

  FIG. 3 is a cross-sectional view illustrating a process of manufacturing the rotor 1 according to FIG. The soft magnetic body 10 has an outer peripheral surface 10a (shown by a broken line) and extends along the central axis P. For example, the outer peripheral surface 10a has a substantially perfect circle when viewed along the central axis P. The outer peripheral surface 10a is deformed into the outer peripheral surface 10b by a process described later.

  The soft magnetic body 10 has a plurality of slots 13, and the slots 13 also extend along the central axis P. The slots 13 are arranged around the central axis P. The slot 13 viewed from the central axis P has a pair of end portions 13b closest to the outer peripheral surface 10a.

  The soft magnetic body 10 has a shaft through hole 15 in the vicinity of the central axis P, which corresponds to the shaft through hole 15 of the rotor 1. Therefore, these shaft through holes 15 are indicated by the same reference numerals.

  The magnet material 14 is injected into the slot 13, whereby the magnet material 14 is molded along the shape of the slot 13. Since such injection molding is well known in Patent Document 2 and the like, its details are omitted. As the magnet material 14, for example, a bond magnet material can be adopted.

  Usually, as suggested in Patent Documents 3 and 4, the deformation of the rotor core due to the injection has been considered undesirable. However, in this application, the deformation | transformation of the soft magnetic body 10 by injection | emission of the magnet material 14 is utilized positively, and the desired shape of the rotor 1 is obtained.

  Specifically, by injecting the magnet material 14 into the slot 13, the outer peripheral surface 10a partially protrudes radially outward to become the outer peripheral surface 10b.

  More specifically, the positions 41 and 42 are introduced and described as follows. The position 41 is a position in the circumferential direction with respect to the central axis P between the adjacent end portions 13b. The position 42 is a circumferential position of the slot 13 away from the end 13b. Since the magnet material 14 is injected into the slot 13, by obtaining the permanent magnet 12 from the magnet material 14 as described later, the position 41 can be grasped between the magnetic poles and the position 42 can be grasped as the magnetic pole center.

  The outer peripheral surface 10 a becomes the outer peripheral surface 10 b further away from the central axis P at the position 42 than at the position 41 as the magnet material 14 is injected into the slot 13. The soft magnetic body 10 deformed in this way becomes the core 11.

  There are two possible reasons why the soft magnetic body 10 is partially deformed in this way. First, since the slot 13 does not exist in the radial direction at the position 41, the soft magnetic body 10 is hardly deformed. Second, since the slot 13 exists in the radial direction at the position 42, the portion (the center portion 13 a) other than the end portion 13 b of the slot 13 is expanded by the injection of the magnet material 14.

  In order to obtain the permanent magnet 12 from the magnet material 14, a well-known magnetization technique can be employed. For example, the magnetizing process may be performed in parallel with the process of injecting the magnet material 14 into the slot 13. Or you may magnetize after the process to inject.

  Further, when the magnet material 14 is injected into the slot 13, the outer peripheral surface 10 a is not prevented from being deformed into the outer peripheral surface 10 b by holding the soft magnetic body 10 in the shaft through hole 15.

  As described above, the soft magnetic body 10 is deformed to become the core 11, and the magnet material 14 becomes the permanent magnet 12, so that the rotor 1 is manufactured.

  4 and 5 are cross-sectional views showing the above process in more detail. FIG. 4 shows the soft magnetic body 10 before the magnet material 14 is injected. FIG. 5 shows the soft magnetic body 10 after the magnet material 14 is injected. By deforming the bridge 101 in this manner, the magnetic characteristics are deteriorated, and the effect of suppressing the short-circuit magnetic flux is improved.

  In addition, the bridge 101 is deformed in a process of injecting the magnet material 14 that is the material of the permanent magnet 12. Therefore, a process required in order to suppress a short circuit magnetic flux can be simplified.

  FIG. 6 is an enlarged sectional view showing the shape of the rotor 1. At the position 41 and its vicinity, the core 11 does not bulge outward in the radial direction, whereas the outer peripheral surface 10b bulges toward the position 42 away from the position 41. Along with this, the bridge 101 is also deformed.

  In order to cause such deformation of the bridge 101, it is desirable to increase the injection amount when the magnet material 14 is injected into the slot 13. Moreover, such an increase in the amount of injection is also desirable from the viewpoint of increasing the volume of the permanent magnet 12 provided in the rotor 1 and thereby increasing the amount of magnetic flux generated by the rotor 1.

  Moreover, from the viewpoint of preventing the deformation of the soft magnetic body 10, the injection amount of the magnet material 14 into the slot 13 is refrained. On the other hand, the increase in the injection amount causes an increase in the contact area between the magnet material 14 and the slot 13. This is also desirable from the viewpoint of improving the adhesion between the magnet material 14 and the soft magnetic body 10, and in turn, the adhesion between the permanent magnet 12 and the core 11.

  The rotor 1 manufactured as described above can obtain the rotating electrical machine 3 by aligning the central axis P with the rotation axis J.

  In addition, it does not ask | require whether the deformation | transformation from the outer peripheral surface 10a to the outer peripheral surface 10b is an elastic deformation or a plastic deformation.

  7 and 8 are cross-sectional views showing other shapes of the end portion 13b. In FIG. 7, the soft magnetic body 10 before injecting the magnet material 14 is shown. FIG. 8 shows the soft magnetic body 10 after the magnet material 14 is injected. Compared with the configuration shown in FIGS. 4 and 5, the end portion 13b has a convex shape with respect to the outer peripheral surface 10a when viewed from the central axis P (see FIG. 3).

  By having such a shape, the stress applied to the soft magnetic body 10 is extensive. Therefore, the deterioration of the magnetic properties of the soft magnetic body 10 including the bridge 101 in the vicinity thereof is extensive. This is desirable from the viewpoint of improving the effect of suppressing the short-circuit magnetic flux.

  Further, the stress applied to the end portion 13b is dispersed as compared with the configuration shown in FIGS. Therefore, as compared with the configuration shown in FIGS. 4 and 5, the bridge 101 is not easily damaged by the deformation of the soft magnetic body 10.

  1 to 8 show the case where the slot 13 has a concave shape with respect to the outer peripheral surfaces 10a and 10b when viewed along the central axis P or the rotation axis J. However, the slot 13 has an end portion 13b, and the slot 13 may have a shape other than that shown in the figure as long as the slot 13 is closest to the outer peripheral surfaces 10a and 10b.

  FIG. 9 is a cross-sectional view showing another embodiment. When viewed along the central axis P, the slot 13 has a concave shape with respect to the outer peripheral surface 10b, and thus has the same shape as the magnet material 14 (and thus the permanent magnet 12).

  FIG. 10 is a sectional view showing still another embodiment. As described above, the shape of the slot 13 may be linear.

  Alternatively, the shape of the slot 13 may be a shape that is inclined with respect to the outer peripheral surfaces 10a and 10b. FIG. 11 is a cross-sectional view exemplifying such a deformation, and exhibits a V-shaped shape with the center portion missing from the outer peripheral surfaces 10a and 10b.

  If the slot 13 is not continuous in the vicinity of the position 42 as shown in FIG. 11, the outer peripheral surface 10 b may not swell with respect to the central axis P at the position 42. This is because the space between the slots 13 near the position 42 prevents the soft magnetic body 10 from being deformed.

  However, even in such a case, since the end portion 13b is separated from the position 42, the deformation of the bridge 101 can be obtained.

DESCRIPTION OF SYMBOLS 1 Rotor 10 Soft magnetic body 10a, 10b Outer peripheral surface 11 Core 12 Permanent magnet 13 Slot 13b End part 14 Magnet material 15 Shaft through-hole 2 Stator 3 Rotating electrical machinery 41, 42 Position J Rotating shaft P Center shaft

Claims (4)

Surrounded by a stator (2) as an armature and provided in the rotating electrical machine (3) together with the stator, facing the stator via a gap (d) in the radial direction with respect to the rotating shaft (J) of the rotating electrical machine And manufacturing a rotor (1) having a core (11) extending along the rotation axis and a permanent magnet (12) embedded in the core,
It has an outer peripheral surface (10a, 10b) and extends along the central axis (P), and an end portion (13b) viewed along the central axis is closest to the outer peripheral surface and around the central axis. In the soft magnetic body (10) in which a plurality of the slots (13) arranged are vacant, the outer peripheral surface and the end portion are deformed by injecting the magnet material (14) into the slot and deforming the soft magnetic body. First step of deforming the soft magnetic body at a position between and deteriorating the magnetic properties of the soft magnetic body (101) at the position to obtain the core;
And a second step of obtaining the permanent magnet by magnetizing the magnet material.   The method of manufacturing a rotor according to claim 1, wherein the end portion has a convex shape with respect to the outer peripheral surface when viewed from the central axis.   The method for manufacturing a rotor according to claim 1, wherein the first step and the second step are performed in parallel. The rotor (1) has a shaft through hole (15) into which the shaft is fitted,
The said 1st process WHEREIN: The said soft-magnetic body is hold | maintained in the shaft through-hole (15) of the said soft-magnetic body (10) corresponding to the said shaft through-hole. Method of manufacturing the rotor.

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