JP2010178600A - Rotating electrical machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating electrical machine capable of reducing iron loss by improving the magnetic characteristics of tooth portions. <P>SOLUTION: The rotating electrical machine includes a rotor, and a stator core which has a cylindrical yoke portion, and a plurality of tooth portions protruded from the yoke portion to the inside of a radial direction of the rotor, provided in the circumferential direction of the yoke portion and formed, by laminating a plurality of electromagnetic steel plates in the shaft direction of the rotor. The rotating electrical machine is provided with a stress applying member press-contacting the tooth portion and applying a compressed stress, in a direction orthogonal to the protruding direction of the tooth portion. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rotating electrical machine such as an electric motor and a generator.

  A stator core of a rotating electrical machine is formed by laminating a plurality of electromagnetic steel sheets (Patent Document 1). As such an electrical steel sheet, a non-oriented electrical steel sheet in which the easy magnetization axis does not have a specific direction, a unidirectional electrical steel sheet in which easy magnetization axes are aligned in one direction, or easy magnetization in a perpendicular direction A bi-directional electrical steel sheet having an axis is used.

  The stator core has a structure having a cylindrical yoke portion and a teeth portion protruding inward in the radial direction of the rotor from the yoke portion. For this reason, it is known that good magnetic characteristics in the circumferential direction for the yoke part and in the protruding direction for the tooth part are preferable in terms of iron loss reduction and motor efficiency. For this reason, a split core type stator core has been proposed in which the tooth portion and the yoke portion are divided and each made of a unidirectional electrical steel sheet.

  Further, Patent Document 2 proposes that a tensile stress in the protruding direction is applied to the teeth portion as a focus on the direction other than the direction of the easy magnetization axis of the electromagnetic steel sheet. In the stator core disclosed in Patent Document 2, a ceramic plate interposed between the tip of the tooth portion and the yoke portion is disposed on the side surface of the tooth portion. And it aims at the improvement of the magnetic characteristic of the protrusion direction of a teeth part by giving a tensile stress to a teeth part with a ceramic board using the thermal contraction of an electromagnetic steel plate.

JP 2002-233090 A JP 2008-17612 A

  However, in the case of a structure in which tensile stress is applied to the teeth portion by interposing a ceramic plate between the tip of the teeth portion and the yoke portion as in Patent Document 2, one end portion of the ceramic plate is near the root of the teeth portion. There is a risk that the yoke portion is in strong contact with the yoke portion, and local radial compressive stress is concentrated on the yoke portion. The vicinity of the root of the tooth portion is a portion through which a large amount of magnetic flux from the tooth portion toward the yoke portion passes, and iron stress increases when compressive stress acts intensively here.

  An object of the present invention is to improve the magnetic characteristics of the tooth portion and reduce iron loss.

  According to the present invention, there is provided a rotor, a cylindrical yoke portion, and a plurality of teeth portions protruding inward in the radial direction of the rotor from the yoke portion and provided in the circumferential direction of the yoke portion. And a stator core formed by laminating a plurality of electromagnetic steel plates in the axial direction of the rotor, and compressive stress in a direction perpendicular to the protruding direction of the tooth portion is applied in pressure contact with the tooth portion. There is provided a rotating electrical machine provided with a stress applying member.

  In this rotating electrical machine, the stress applying member applies a compressive stress in a direction orthogonal to the protruding direction of the tooth portion to the tooth portion, thereby improving the magnetic characteristics in the protruding direction of the tooth portion. Therefore, the magnetic characteristics of the teeth portion can be improved and the iron loss can be reduced.

  In the present invention, the coil includes a coil wound around the tooth portion, and the stress applying member is separated from the root portion and the tip portion at a portion between the root portion and the tip portion of the tooth portion. The coil is pressed against the teeth portion, and the coil is wound around the tooth portion via the stress applying member and the stress applying member at a portion where the stress applying member is not pressed against the tooth portion. And a portion wound around the teeth portion without being interposed therebetween. According to this configuration, the coil winding amount can be secured by using the space between the stress applying member and the yoke portion or the tip portion as the coil arrangement space.

  In the present invention, the stress applying member is a cylindrical body that is provided for each tooth portion and surrounds the tooth portion, and the cylindrical body is joined to each other to constitute the cylindrical body. It may consist of. According to this configuration, compressive stress can be applied to the teeth portion by the cylindrical body.

  In the present invention, the stress applying member may be a cylindrical body that is interposed between the tooth portions and has an opening in a direction parallel to the axial direction of the rotor. According to this configuration, it is possible to apply compressive stress to the teeth portion by the cylindrical body while securing a space for arranging the coil.

  In the present invention, the stress applying member may be a belt provided for each tooth portion and wound around the tooth portion. According to this configuration, compressive stress can be applied to the teeth portion by the band.

  As described above, according to the present invention, the magnetic characteristics of the tooth portion can be improved and the iron loss can be reduced.

(A) is sectional drawing of the rotary electric machine A which concerns on 1st Embodiment of this invention, (b) is sectional drawing of the rotary electric machine A in alignment with line XX of Fig.1 (a). (A) is a perspective view of the electromagnetic steel sheet 23, and (b) is a perspective view of the stress applying member 50 provided in the tooth portion 21. (A) And (b) is a disassembled perspective view which shows the structural example of the stress addition member 50, (c) is a figure which shows the structural example which integrated all the division bodies 54. FIG. (A) is sectional drawing which shows the joining structure of the division bodies 51 and 52, (b) is a figure which shows the arrangement | positioning state of the coil 30. FIG. (A) is explanatory drawing of the compressive stress added to the teeth part 21 by the stress addition member 50, (b) is explanatory drawing which shows the dimension of the stress addition member 50, (c) is the teeth in 2nd Embodiment of this invention. It is explanatory drawing of part 21 'and stress addition member 50'. (A) is explanatory drawing of the stress application member 150 in 3rd Embodiment of this invention, (b) is a perspective view of the stress application member 150. FIG. It is explanatory drawing of the stress addition member 250 in 4th Embodiment of this invention.

<First Embodiment>
FIG. 1A is a cross-sectional view of the rotating electrical machine A according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view of the rotating electrical machine A along the line XX of FIG. The rotating electrical machine A is an electric motor or a generator, and includes a rotor 10, a stator core 20, a coil 30, a case 40, and a stress applying member 50. The rotor 10 includes a rotor shaft 11 and a plurality of permanent magnets (not shown) disposed around the rotor shaft. Hereinafter, the axial direction, the circumferential direction, and the radial direction refer to the axial direction (including a direction parallel to the axial direction), the circumferential direction, and the radial direction of the rotor 10 unless otherwise specified.

  The stator core 20 has a cylindrical yoke portion 22 concentric with the rotor 10 and teeth that protrude radially inward from the yoke portion 22 and are provided at equal intervals in the circumferential direction of the yoke portion 22 (eight in this embodiment). And a coil 30 is wound around each tooth portion 21. The stator core 20 is a laminate of a plurality of electromagnetic steel plates 23 laminated in the axial direction. FIG. 2A is a perspective view of the electromagnetic steel plate 23, in which a portion constituting the tooth portion 21 and a portion constituting the yoke portion 22 are integrally formed.

  In the present embodiment, the stator core 20 is formed by laminating one electromagnetic steel plate 23 in the circumferential direction in the circumferential direction. However, the split core method is configured by dividing the teeth portion and the yoke portion and respectively unidirectional electromagnetic steel plates. The stator core may be used.

  Referring to FIGS. 1A and 1B, case 40 is made of a metal such as an aluminum alloy, for example, and forms a cylindrical body into which stator core 20 is inserted. In FIGS. 1A and 1B, both end portions of the stator core 20 in the axial direction are open, but end members (not shown) for supporting the rotor shaft 11 are provided at the respective end portions. The end member can be configured by being fixed to the case 40 separately from the case 40, but one of the end members may be integrated with the case 40.

  The stress applying member 50 is provided for each tooth part, presses against the tooth part 21, and applies a compressive stress in a direction orthogonal to the protruding direction of the tooth part 21 to the tooth part 21. The material of the stress applying member 50 is a nonmagnetic material, and for example, a nonmagnetic metal material such as an aluminum alloy or austenitic SUS can be used.

  FIG. 2B is a perspective view of the stress applying member 50 provided in the tooth portion 21. In the case of the present embodiment, the stress applying member 50 includes a pair of wall portions 50a that are pressed against each side surface in the circumferential direction of the teeth portion 21, a pair of wall portions 50b that are pressed against each side surface in the axial direction of the teeth portion 21, This is a rectangular cylinder surrounding the teeth portion 21.

  In the case of this embodiment, since the front-end | tip part 21a of the teeth part 21 is wider than another part, the stress application member 50 is comprised from the several division body which mutually joins and comprises a cylinder. . 3A and 3B are exploded perspective views showing a configuration example of the stress applying member 50. FIG. In any of these configuration examples, the stress applying member 50 is divided into two parts, but may be divided into three parts or more. However, in consideration of convenience during assembly, a two-part structure is desirable.

  The example of Fig.3 (a) is comprised from the division bodies 51 and 52 which divided the stress addition member 50 into 2 in the circumferential direction. In the example of FIG. 3B, the stress applying member 50 is composed of divided bodies 53 and 54 that are divided into two in the axial direction. In the case of the example of FIG. 3B, the divided bodies 53 and 54 may be arranged annularly in the circumferential direction according to each tooth portion 21, and may be integrated for each of the divided body 53 and the divided body 54. FIG. 3C is a diagram showing a configuration example in which all the divided bodies 54 are integrated, and by integrating the ring-shaped member and each divided body 54, all the divided bodies 54 are integrated. Is.

  As a method for joining the divided bodies, mechanical engagement may be used in addition to welding, and any joining may be used as long as it can be firmly joined. In the case of welding or the like, the configuration divided into two in the circumferential direction as in the example of FIG.

  FIG. 4A is a cross-sectional view showing the joining structure of the divided bodies 51 and 52, and shows an example of a mechanical engagement structure. The same kind of structure can also be used for joining the divided bodies 53 and 54. In the example of FIG. 4A, at each joint end face of the divided bodies 51, 52, the divided body 51 is provided with a protruding portion 51a, and the divided body 52 is formed with a groove 52a into which the protruding portion 51a is fitted. is there. The protrusion 51a and the groove 52a can be formed linearly in the longitudinal direction of the joint end face. When the protrusion 51a and the groove 52a are fitted, the groove 52a may be expanded and slightly plastically deformed. However, since the coil 30 is wound around the stress applying member 50, the deformation is eliminated.

  When the stress applying member 50 is provided, the space between the tooth portions 21 is reduced, and the space for arranging the coil 30 is smaller than when the stress applying member 50 is not provided. In the present embodiment, the stress applying member 50 is disposed so that the stress applying member 50 is in pressure contact with the tooth portion 21 at a portion between the root portion and the tip end portion 21a of the tooth portion 21 and spaced apart from the tip portion and the root portion. A radial width of 50 is set. The coil 30 is directly wound around the tooth portion 21 on the tip portion 21a side and the root portion side.

  FIG. 4B is a diagram showing the arrangement state of the coil 30, and in particular, in the vicinity of the stress applying member 50, the arrangement of the individual coil windings 31 is shown in detail. As shown in the figure, in the region R <b> 2 where the stress applying member 50 is in pressure contact with the tooth portion 21, the coil winding 31 is wound around the tooth portion 21 via the stress applying member 50, and the stress applying member 50 is wound on the tooth portion 21. In the region R1 on the base portion side and the region R3 on the tip portion 21a side that are not pressed against each other, the coil winding 31 is directly wound around the tooth portion 21 without the stress applying member 50 interposed therebetween. Thus, the amount of winding of the coil 30 can be ensured by using the regions R1 and R3 as the arrangement space of the coil 30.

  Needless to say, a sheet or the like is provided between the coil winding 31 and the stator core 20 so as to be insulated. Further, separating the stress applying member 50 from the root portion and the tip end portion 21 a of the tooth portion 21 means that the stress applying member 50 imparts compressive stress to the yoke portion 22 around the root of the tooth portion 21. There is also an effect that it can be surely avoided.

  In the rotating electrical machine A having such a configuration, the stress applying member 50 applies a compressive stress in a direction orthogonal to the protruding direction of the tooth portion 21 to the tooth portion 21, so that the protruding direction of the tooth portion 21, that is, the direction in which the magnetic flux flows. Magnetic characteristics can be improved and the iron loss can be reduced. FIG. 5A is an explanatory diagram of the compressive stress applied to the tooth portion 21 by the stress applying member 50.

  When subjected to compressive stress, the electrical steel sheet has a property that magnetic properties in a direction perpendicular to the compression direction are improved. This is considered to be because when a compressive stress is applied, the magnetic domains are easily oriented in a direction perpendicular to the compression direction. In the case of this embodiment, as shown in FIG. 5A, the stress applying member 50 applies a circumferential compressive stress indicated by an arrow d2 and an axial compressive stress indicated by an arrow d3 to the tooth portion 21. The For this reason, the magnetic characteristic of the protrusion direction of the teeth part 21 shown by the arrow d1 is improved. In this embodiment, the stress applying member 50 applies a circumferential compressive stress indicated by an arrow d2 and an axial compressive stress indicated by an arrow d3, but applies a compressive stress in either the circumferential direction or the axial direction. You may make it do.

  The stress can be applied as a residual stress utilizing thermal expansion and contraction of the material. For example, the stress applying member 50 is attached to the tooth portion 21 in a state of being heated and thermally expanded, and the stress is applied by returning to the normal temperature. At this time, the compressive stress can be controlled by the dimensions of the stress applying member 50 at room temperature. FIG. 5B is an explanatory view showing the dimensions of the stress applying member 50. By setting the width W1 between the wall portions 50a at normal temperature to be shorter than the circumferential width of the teeth portion 21, the circumferential compressive stress indicated by the arrow d2 in FIG. 5A can be applied to the teeth portion 21. The magnitude of the compressive stress can be changed depending on the degree of dimensional difference. Similarly, by setting the width W2 between the wall portions 50b at normal temperature to be shorter than the width in the axial direction of the tooth portion 21, the axial compressive stress indicated by the arrow d3 in FIG. The magnitude of the compressive stress can be changed according to the degree of dimensional difference.

<Second Embodiment>
In the said 1st Embodiment, except for the front-end | tip part 21a, the width | variety of the circumferential direction of the teeth part 21 was made uniform, but you may narrow the circumferential width | variety as it goes to the front-end | tip part 21a from a root part. By doing in this way, the arrangement | positioning space of the coil 30 can be expanded rather than the structure of the said 1st Embodiment. In this case, it is assumed that the wall portion 50 a of the stress applying member 50 also follows the shape of the tooth portion 21.

  FIG.5 (c) is explanatory drawing of teeth part 21 'and stress application member 50' in 2nd Embodiment of this invention. The tooth portion 21 ′ has a width in the circumferential direction of the root portion of W11 and a width in the circumferential direction of the tip portion 21a ′ of W12 (<W11), and the tooth portion 21 ′ has a circumferential width from the root portion toward the tip portion 21a ′. The direction width is narrow.

  The stress applying member 50 ′ has a pair of wall portions 50 a ′ that press-contact with each side surface in the circumferential direction of the tooth portion 21, following the shape of the tooth portion 21 ′, and the width between the wall portions 50 a ′ is the teeth. It is large on the base portion side of the portion 21 'and small on the tip portion 21a' side.

  In the case of the present embodiment, since the circumferential width on the tip portion 21a ′ side of the tooth portion 21 ′ is narrow, it is desirable that the magnetic properties are relatively good on the tip portion 21a ′ side. On the other hand, the improvement in magnetic properties by applying compressive stress is proportional to the magnitude of the compressive stress within a certain range. Therefore, it is preferable that the compressive stress by the stress applying member 50 ′ is relatively small on the root portion side and relatively large on the tip portion 21a ′ side, as indicated by the length of the arrow in FIG. As described above, the magnitude of the compressive stress can be controlled by the dimension of the stress applying member 50 ′ at room temperature, and the difference in the room temperature between the circumferential width of the tooth portion 21 ′ and the width of the wall portion 50a ′ can be obtained by: What is necessary is just to make it comparatively small by the base part side and relatively large by the front-end | tip part 21a 'side.

<Third Embodiment>
In the said 1st Embodiment, although the stress addition member was comprised with the cylinder surrounding the teeth part 21, you may comprise with the member interposed between the teeth parts 21. FIG. FIG. 6A is an explanatory view of the stress applying member 150 according to the third embodiment of the present invention, and FIG. 6B is a perspective view of the stress applying member 150.

  The stress applying member 150 is a cylindrical body having an opening portion 151 in the axial direction, and is disposed between the tooth portions 21. The opening 151 is a space for winding the coil 30. As shown in FIG. 4B of the first embodiment, when a space where the stress applying member 150 is not in pressure contact is provided on the root portion side and the tip portion side of the tooth portion 21, the opening portion In addition to 151, the space can also be used as a space for winding the coil 30. In this case, the coil 30 can be directly wound around the tooth portion 21 as in the regions R1 and R3 in FIG. It is also possible to combine this embodiment and the second embodiment.

  The stress applying member 150 includes a pair of wall portions 150a that press against the circumferential side surface of the teeth portion 21, and the width at room temperature between the wall portions 150a is set between the circumferential side surfaces of the adjacent tooth portions 21. By making it larger than the width, a compressive stress in the circumferential direction can be applied to the tooth portion 21. The stress applying member 150 can be provided by being press-fitted between the tooth portions 21. In addition, the stator core 20 is heated and thermally expanded, and the stress applying member 150 is disposed between the teeth portions 21 when the stator core 20 is thermally expanded, and compressive stress is applied by utilizing the fact that the stator core 20 returns to normal temperature and contracts. You may make it do.

  Moreover, the tensile stress of the protrusion direction can also be added with respect to the teeth part 21 by making the width Wa of the radial direction of the wall part 150a larger than the width Wt from the root part of the teeth part 21 to the front-end | tip part 21a. Thereby, the magnetic characteristic of the protrusion direction of the teeth part 21 can further be improved. In this case, compressive stress acts on the yoke portion 22, but in the present embodiment, the wall portion 150 b is formed following the inner peripheral surface of the yoke portion 22 and is in contact with the surface. For this reason, it can avoid that a local nominal compressive stress acts intensively in the base vicinity of the teeth part 21, and can suppress the increase in the iron loss by the concentration of the radial compressive stress with respect to the yoke part 22. FIG.

  The stress applying member 150 may be annularly arranged in the circumferential direction according to the arrangement space between the tooth portions 21, and the total stress adding member 150 may be integrated as in the configuration example of FIG.

<Fourth embodiment>
In the first and third embodiments, the stress applying member is formed of a cylindrical body, but may be a belt provided for each tooth portion 21 and wound around the tooth portion 21. FIG. 7 is an explanatory diagram of a stress applying member 250 according to the fourth embodiment of the present invention. The stress applying member 250 is a single band, and is provided by being wound around the teeth portion 21 a plurality of times while applying tension to the band. And the compressive stress according to the degree of tension of the belt at the time of winding is added to teeth part 21. The stress applying member 250 is, for example, a strip-shaped metal foil having a thickness of 50 μm to 100 μm, and is a nonmagnetic metal foil such as austenitic SUS.

  In addition, when the space which the stress application member 250 does not press-contact is provided in the root part side of the teeth part 21, and the front-end | tip part side like the structure of FIG.4 (b) of the said 1st Embodiment, this space Can also be used as a space for winding the coil 30. In this case, the coil 30 can be directly wound around the teeth portion 21 as in the regions R1 and R3 of FIG. 4B. It is also possible to combine this embodiment and the second embodiment. When making a difference in compressive stress between the root part side and the tip part side of the teeth part, the tension at the time of winding is changed depending on the part, or two or more belts are wound around one tooth part 21 The tension at the time of winding can be changed for each band.

A Rotating electrical machine 10 Rotor 20 Stator core 21 Teeth part 22 Yoke part 23 Electrical steel sheet 40 Cases 50, 150, 250 Stress applying member

Claims (5)

A rotor,
A cylindrical yoke portion, and a plurality of teeth portions protruding inward in the radial direction of the rotor from the yoke portion and provided in the circumferential direction of the yoke portion, and a plurality of electromagnetic steel plates are arranged in the axial direction of the rotor A stator core formed by laminating to,
In a rotating electrical machine with
A rotating electrical machine comprising a stress applying member that presses against the tooth portion and applies a compressive stress in a direction orthogonal to a protruding direction of the tooth portion. Comprising a coil wound around the teeth portion;
The stress applying member is in pressure contact with the teeth portion at a portion between the root portion and the tip portion of the tooth portion, being separated from the root portion and the tip portion, respectively.
The coil is
A portion wound around the teeth portion via the stress applying member;
A portion wound around the teeth portion without the stress applying member in a portion where the stress applying member is not pressed against the teeth portion;
The rotating electrical machine according to claim 1, comprising: The stress applying member is provided for each tooth portion, and is a cylindrical body surrounding the tooth portion,
The rotating electrical machine according to claim 1, wherein the cylindrical body is composed of a plurality of divided bodies that are joined together to form the cylindrical body.   3. The rotating electrical machine according to claim 1, wherein the stress applying member is a cylindrical body that is interposed between the teeth portions and has an opening in a direction parallel to the axial direction of the rotor.   3. The rotating electrical machine according to claim 1, wherein the stress applying member is a belt that is provided for each tooth portion and is wound around the tooth portion.

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