JP2017153197A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary machine having a new structure capable of supporting a stator without imparting compressive stress to a back yoke of the stator.SOLUTION: A stator 10 includes: an annular back yoke 11; and a plurality of teeth 12 protruding inward from the back yoke. A rotor 20 is arranged inside the stator. The rotor is rotatably supported by a bearing 32. A biasing member 40 disposed inside the back yoke imparts a tensile stress in the circumferential direction to the back yoke.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotating machine including a stator and a rotor.

  A stator having a cylindrical outer shape is accommodated in a cylindrical case. The stator can be fixed to the case by shrink-fitting the stator in the case. When the fixing method by shrink fitting is adopted, a circumferential compressive stress is applied to the annular back yoke that is a part of the stator. A circumferential magnetic flux is generated in the back yoke. When a compressive stress parallel to the magnetic flux is applied to the back yoke, the iron loss increases. As a result, the efficiency of the rotating machine is reduced.

  Patent Document 1 listed below discloses a rotating machine that alleviates deterioration of magnetic properties caused by compressive stress. In the rotating machine disclosed in Patent Document 1, the outer peripheral surface of the stator is divided into a region that contacts the housing (contact region) and a region that does not contact (non-contact region). The contact area and the non-contact area are alternately arranged in the circumferential direction. With this structure, the compressive stress applied to the stator back yoke is relieved.

JP 2008-193778 A

  An object of the present invention is to provide a rotating machine having a new structure capable of supporting a stator without applying compressive stress to the back yoke of the stator.

According to one aspect of the invention,
A stator including an annular back yoke and a plurality of teeth projecting inwardly from the back yoke;
A rotor disposed inside the stator;
A bearing that rotatably supports the rotor;
There is provided a rotating machine having an urging member disposed inside the back yoke and imparting a tensile stress in the circumferential direction to the back yoke.

According to another aspect of the invention,
A rotor,
A bearing that rotatably supports the rotor;
A stator that surrounds the rotor in the circumferential direction and includes a back yoke in which circumferential strain is generated, and a plurality of teeth protruding from the back yoke toward the rotor;
There is provided a rotating machine having an urging member that causes an elongation strain in a circumferential direction on the back yoke.

  By the biasing member, circumferential tensile stress is applied to the back yoke, or circumferential elongation strain occurs. As a result, the magnetic properties of the back yoke are improved, and the efficiency of the rotating machine can be increased.

FIG. 1A is a cross-sectional view including a central axis of a rotating machine according to an embodiment, and FIG. 1B is a cross-sectional view of the rotating machine in an intermediate stage of assembly. FIG. 2 is a cross-sectional view perpendicular to the rotation axis of the rotating machine according to the embodiment. FIG. 3 is a perspective view of a biasing member used in the rotating machine according to the embodiment. FIG. 4 is a cross-sectional view perpendicular to the rotation axis of a rotating machine according to another embodiment. FIG. 5 is a perspective view of a biasing member used in the rotating machine according to the embodiment shown in FIG. FIG. 6 is a cross-sectional view perpendicular to the rotation axis of a rotating machine according to still another embodiment. FIG. 7 is a cross-sectional view including the central axis of the rotating machine according to the embodiment shown in FIG. FIG. 8 is a cross-sectional view including a central axis of a rotating machine according to still another embodiment.

With reference to FIG. 1A and FIG. 1B-FIG. 3, the rotary machine by an Example is demonstrated.
FIG. 1A is a cross-sectional view including the central axis of the rotating machine according to the present embodiment. The rotating machine includes a stator 10, a rotor 20, and a rotating shaft 30.

  The stator 10 is formed by laminating a large number of thin plate-shaped electromagnetic steel plates that have been punched into the same shape. The thickness of the electromagnetic steel sheet is about 0.5 mm, for example. The stator 10 includes an annular back yoke 11 and a plurality of teeth 12. The plurality of teeth 12 protrudes inward from the back yoke 11. In the cross-sectional view of FIG. 1A, a portion where the teeth 12 are not arranged is shown, and a side surface of the teeth 12 appears. A coil (not shown in FIG. 1A) made of a conductive wire is wound around each of the teeth 12.

  The rotor 20 is disposed inside the stator 10. The rotor 20 is also formed by laminating a number of thin plate-shaped electromagnetic steel plates that have been punched into the same shape. The rotor 20 is formed with a circular hole for inserting the rotary shaft 30 at the center. The rotating shaft 30 is fixed to the rotor 20 by an interference fit.

  As the rotor 20, for example, a cage rotor is used. The cage rotor includes a plurality of conductor bars 21 and a pair of end rings 22. Each of the conductor bars 21 is long in a direction parallel to the axial direction of the rotating shaft 30 and is arranged at equal intervals in the circumferential direction. The end rings 22 are disposed on both end faces of the rotor 20, connected to the ends of the plurality of conductor bars 21, and short-circuit between the conductor bars 21.

  The rotating shaft 30 is supported by a pair of bearings 31 and 32 so as to be rotatable with respect to the end plates 33 and 34, respectively. The inner rings of the bearings 31 and 32 are supported on the rotary shaft 30 by a general support structure. The outer rings of the bearings 31 and 32 are respectively supported by the end plates 33 and 34 by a general support structure. A fan 36 is attached to one end of the rotating shaft 30. The fan 36 is covered with a fan cover 37.

  A plurality of biasing members 40 extend from one end plate 33 to the other end plate 34. The biasing member 40 is supported by the end plates 33 and 34 by inserting both ends of the biasing member 40 into grooves 33A and 34A formed in the end plates 33 and 34, respectively. Each of the urging members 40 is disposed on the inner side of the back yoke 11 and applies a radial force toward the outer side to the back yoke 11. By this force, a circumferential tensile stress is applied to the back yoke 11.

  The end plates 33 and 34 are fixed to each other by a fastener 35 including a plurality of through bolts 35A and nuts 35B. When the fastener 35 is tightened, the end plates 33 and 34 are displaced in a direction approaching each other. As the urging member 40, an elastic member, for example, a leaf spring is used. When the end plates 33 and 34 are displaced in the approaching direction, the urging member 40 is elastically deformed so as to expand outward. When the urging member 40 swells outward, a radial force is applied outward from the urging member 40 to the back yoke 11. The stator 10 is supported with respect to the rotor 20, the rotary shaft 30, the bearings 31 and 32, and the end plates 33 and 34 by the frictional force generated on the contact surface between the urging member 40 and the back yoke 11. In other words, the rotor 20 is instructed to be rotatable with respect to the stator 10 by the support structure including the biasing member 40 and the end plates 33 and 34 and the bearings 31 and 32.

  FIG. 1B shows a cross-sectional view of the rotating machine in the middle of assembly. The rotary shaft 30 is supported on the lower end plate 33 via a bearing 31. The lower end of the biasing member 40 is inserted into the groove 33 </ b> A of the end plate 33. The stator 10 is held at a normal position with respect to the end plate 33 by an assembly jig or the like. A bearing 32 supported by the upper end plate 34 is fitted in the vicinity of the upper end of the rotary shaft 30. The upper end of the urging member 40 does not reach the upper end plate 34 and is not elastically deformed. In this state, the urging member 40 does not apply a force to the back yoke 11.

  While the upper end plate 34 is brought close to the lower end plate 33, the upper end of the urging member 40 is inserted into the groove 34 </ b> A formed in the end plate 34. When the fastener 35 is tightened to bring the upper end plate 34 closer to the lower end plate 33, the biasing member 40 is elastically deformed to apply a force to the back yoke 11, and the stator 10 is biased to the biasing member 40. Are supported by the end plates 33 and 34.

  FIG. 2 shows a cross-sectional view perpendicular to the rotating shaft 30 of the rotating machine according to the embodiment. Stator 10 includes an annular back yoke 11 and a plurality of teeth 12. The teeth 12 protrude inward from the back yoke 11. Although FIG. 2 shows an example in which six teeth 12 are provided, the number of teeth 12 is not limited to six. For example, the number of teeth 12 may be 36, 48, or the like. A coil 13 is wound around each tooth 12. A rotor 20 is disposed inside the stator 10. A rotating shaft 30 is fixed to the center of the rotor 20.

  The biasing member 40 is arrange | positioned between the two teeth 12 adjacent to the circumferential direction, respectively. The shape of the inner peripheral surface of the back yoke 11 is a cylindrical shape. The surface of the urging member 40 that faces the back yoke 11 has a shape that follows the inner peripheral surface of the back yoke 11. That is, the shape of the surface facing the outside of the urging member 40 is a cylindrical shape having the same curvature as the inner peripheral surface of the back yoke 11. For this reason, the surface facing the outside of the urging member 40 is in close contact with the inner peripheral surface of the back yoke 11. Thereby, it is possible to efficiently apply an outward radial force to the back yoke 11.

  FIG. 3 shows a perspective view of the urging member 40. The biasing member 40 has a shape that is long in the vertical direction, and the central portion 41 projects in one direction from a virtual plane including both ends 42 and 43 of the biasing member 40. The surface of the central portion 41 is formed in a cylindrical shape and contacts the inner peripheral surface of the back yoke 11 (FIG. 1A).

  The area | region from the both ends 42 and 43 of the biasing member 40 to the center part 41 contains the inclination parts 44 and 45, respectively. When the both ends 42 and 43 of the urging member 40 are displaced in the approaching direction, the inclination of the inclined portions 44 and 45 with respect to a virtual plane including the both ends 42 and 43 becomes steep, so that the projection amount of the central portion 41 is increased. growing.

  In FIG. 3, the urging member 40 is connected at the connecting portion between the inclined portions 44, 45 and the central portion 41 and at the connecting portion between the inclined portions 44, 45 and the portions extending from the inclined portions 44, 45 to both ends 42, 43. An example of bending is shown. As another configuration example, the biasing member 40 may be smoothly curved at these connection points.

  For example, stainless steel is used for the urging member 40. The urging member 40 can be produced by pressing a flat plate made of stainless steel.

Next, effects of the embodiment shown in FIGS. 1A and 1B to 3 will be described.
As shown in FIG. 2, the urging member 40 applies a radial force directed outward to the back yoke 11. By this force, a circumferential tensile stress is applied to the back yoke 11, and a circumferential extension strain is generated. When an excitation current flows through the coil 13, a circumferential magnetic flux is generated in the back yoke 11. By applying a tensile stress to the back yoke 11 in a direction parallel to the magnetic flux, the magnetic properties of the back yoke 11 are improved. Specifically, the magnetic permeability of the back yoke 11 is increased. Thereby, the efficiency improvement of a rotary machine can be aimed at.

  In the embodiment shown in FIGS. 1A and 1B to 3, the urging member 40 is a part of a support structure that supports the rotor 20 with respect to the stator 10. As another configuration, the rotor 20 may be supported by a support structure that does not include the biasing member 40. In this case, the urging member 40 only needs to have a function of applying a tensile stress in the circumferential direction to the stator 10.

  Next, with reference to FIG.4 and FIG.5, the rotary machine by another Example is demonstrated. Hereinafter, differences from the embodiment shown in FIGS. 1A and 1B to 3 will be described, and description of common configurations will be omitted.

  FIG. 4 shows a cross-sectional view perpendicular to the rotation axis of the rotating machine according to this embodiment. In the embodiment shown in FIG. 2, the inner peripheral surface of the back yoke 11 and the surface facing the outside of the urging member 40 are cylindrical. In the present embodiment, a plurality of planar regions 14 are provided on the inner peripheral surface of the back yoke 11. The plurality of planar regions 14 are arranged between the teeth 12 adjacent to each other in the circumferential direction. The surface facing the outside of the biasing member 40 is a flat surface and contacts the flat region 14 of the back yoke 11.

  FIG. 5 is a perspective view of the urging member 40 used in the rotating machine according to the present embodiment. In the present embodiment, the surface facing the outside of the central portion 41 is a flat surface. The surface facing the outside of the central portion 41 is brought into close contact with the flat area 14 (FIG. 4) of the back yoke 11, whereby a radial force directed outward is applied from the biasing member 40 to the back yoke 11. .

  Also in this embodiment, the same effects as those of the embodiment shown in FIGS. 1A and 1B to 3 can be obtained. Furthermore, since the central portion 41 of the urging member 40 has a flat plate shape, the surface of the central portion 41 can be easily manufactured as compared with the urging member 40 having a cylindrical shape (FIG. 3). Furthermore, in this embodiment, since the flat surfaces of the urging member 40 and the back yoke 11 are in close contact with each other, the in-plane uniformity of the degree of adhesion can be easily increased.

  Next, a rotating machine according to still another embodiment will be described with reference to FIGS. Hereinafter, differences from the embodiment shown in FIGS. 1A and 1B to 3 will be described, and description of common configurations will be omitted.

  FIG. 6 shows a cross-sectional view perpendicular to the rotation axis of the rotating machine according to this embodiment. The biasing member 40 is arrange | positioned between the two teeth 12 adjacent to the circumferential direction, respectively. Each urging member 40 contacts the inner peripheral surface of the back yoke 11 and reaches from one tooth 12 to the other tooth 12. That is, the end surfaces at both ends in the circumferential direction of the urging member 40 are in contact with the teeth 12.

  The urging member 40 is inserted between the teeth 12 by, for example, cold fitting. When the urging member 40 is thermally expanded after the cold fitting, the urging member 40 is firmly fixed to the stator 10 and a circumferential tensile stress is applied to the back yoke 11 between the teeth 12. The

  FIG. 7 shows a cross-sectional view including the central axis of the rotating machine according to this embodiment. The biasing member 40 reaches from the lower end plate 33 to the upper end plate 34. In the cross section along the axial direction of the rotating shaft 30, the biasing member 40 is linear. The urging member 40 is fixed to the end plates 33 and 34 by inserting the lower end and the upper end of the urging member 40 into grooves 33A and 34A formed in the end plates 33 and 34, respectively.

  Also in this embodiment, since the tensile stress in the circumferential direction is applied to the back yoke 11 (FIG. 6), the magnetic properties of the back yoke 11 are improved as in the embodiments shown in FIGS. 1A and 1B to 3. can do.

  In the present embodiment, when the biasing member 40 is thermally expanded, a circumferential compressive force is applied to the base portion of the tooth 12 sandwiched between the biasing members 40. However, since a radial magnetic flux is generated in the tooth 12, the direction of the compressive force and the direction of the magnetic flux are substantially orthogonal. For this reason, the compressive force applied to the base of the tooth 12 does not adversely affect the magnetic characteristics of the tooth 12.

  Next, a rotating machine according to still another embodiment will be described with reference to FIG. Hereinafter, differences from the embodiment shown in FIGS. 1A and 1B to 3 will be described, and description of common configurations will be omitted.

  FIG. 8 is a cross-sectional view including the central axis of the rotating machine according to the present embodiment. In the present embodiment, a side case 38 is disposed between the end plates 33 and 34. The side case 38 has a cylindrical shape surrounding the stator 10 and is fixed to the end plates 33 and 34. Since the stator 10 is supported by the end plates 33 and 34 by the urging member 40, the side case 38 does not need to have a function of supporting the stator 10. A gap may be secured between the inner peripheral surface of the side case 38 and the outer surface of the stator 10, or both may be brought into contact with each other.

  Conventionally, the stator 10 may be fixed by shrink fitting to the side case 38. By this shrink fitting, a circumferential compressive stress is applied to the back yoke 11 of the stator 10. In the present embodiment, since it is not necessary to shrink fit the stator 10 to the side case 38, it is possible to prevent the circumferential compressive stress from being applied to the back yoke 11 of the stator 10.

  Furthermore, in the present embodiment, by arranging the side case 38, the hermeticity inside the stator 10 can be improved.

  Note that the stator 10 may be shrink-fitted into the side case 38. In this case, a circumferential compressive stress is applied from the side case 38 to the back yoke 11 of the stator 10, but a circumferential tensile stress is also applied from the biasing member 40. For this reason, the influence of compressive stress can be reduced. Further, since the stator 10 is supported by the side case 38, the support function of the stator 10 by the biasing member 40 can be weakened. For example, the urging member 40 can be optimized for the function of applying a circumferential tensile stress to the back yoke 11.

  In the above embodiment, a rotating machine using a squirrel-cage rotor, such as an electric motor and a generator, has been described. It is also possible to do.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

10 Stator 11 Back yoke 12 Teeth 13 Coil 14 Plane region 20 Rotor 21 Conductor bar 22 End ring 30 Rotating shaft 31, 32 Bearing 33, 34 End plate 33A, 34A Groove 35 Fastener 35A Through bolt 35B Nut 36 Fan 37 Fan cover 38 Side case 40 Biasing member 41 Central portions 42, 43 Both ends 44, 45 of the biasing member

Claims (7)

A stator including an annular back yoke and a plurality of teeth projecting inwardly from the back yoke;
A rotor disposed inside the stator;
A bearing that rotatably supports the rotor;
A rotating machine having an urging member disposed inside the back yoke and imparting a tensile stress in the circumferential direction to the back yoke.   The rotating machine according to claim 1, wherein the biasing member includes an elastic member that is elastically deformed, and the elastic member is elastically deformed to apply a force directed from the inside to the outside to the back yoke.   The rotating machine according to claim 2, wherein an inner peripheral surface of the back yoke has a cylindrical shape, and a surface of the elastic member that faces the back yoke has a shape that follows the inner peripheral surface of the back yoke.   3. The rotating machine according to claim 2, wherein the inner peripheral surface of the back yoke includes a planar portion, and the elastic member includes a planar surface facing the planar portion of the inner peripheral surface of the back yoke.   The said biasing member is arrange | positioned between the said teeth adjacent to the circumferential direction, The tensile stress of the circumferential direction is provided, The tensile stress is given to the said back yoke in the circumferential direction. Rotating machine. A rotor,
A bearing that rotatably supports the rotor;
A stator that surrounds the rotor in the circumferential direction and includes a back yoke in which circumferential strain is generated, and a plurality of teeth protruding from the back yoke toward the rotor;
A rotating machine having an urging member causing circumferential strain in the back yoke.   The rotating machine according to claim 6, wherein the biasing member is disposed inside the back yoke.

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