JP2014147253A - Induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction motor which comprises a rotor disposed with a secondary conductor including a plurality of conductor bars and an end ring, and a stator, suppressing breakage/deformation of the secondary conductor owing to centrifugal force accompanied by higher speed rotation.SOLUTION: An induction motor 1 includes a rotor 10 constituted as a squirrel cage rotor, and a stator 50 for generating a rotating magnetic field. The rotor 10 has a rotary shaft 15, a rotor core 20, and a secondary conductor 30 including a plurality of conductor bars 31 and an end ring 35. The plurality of conductor bars 31 are distributedly arranged at constant intervals circumferentially of the rotor core 20 so as to surround the rotary shaft 15, and are joined respectively to the end ring 35 arranged along axial end face of the rotor core 20. An outer-diameter-side end portion 31O at an axial end portion 31E of each conductor bar 31 is formed in such a manner as drawing an arc of a second radially outer radius Rb greater than a first outer-diameter-side radius Ra of the outer-diameter-side end portion 31O at an axially central portion 31C.

Description

  The present invention relates to an induction motor having a rotor having a plurality of conductor bars and a secondary conductor including an end ring and a stator.

  Conventionally, one of induction motors using a so-called cage rotor is known. The squirrel-cage rotor rotates on a rotor core fixed to a rotation shaft, a plurality of conductor bars disposed in a plurality of slots formed around the rotation shaft, and an axial end surface of the rotor core. It is comprised by the secondary conductor containing the end-ring ring (end ring) comprised by the cyclic | annular form surrounding the circumference | surroundings of an axis | shaft. In the induction motor, the squirrel-cage rotor is configured to rotate by the interaction between a rotating magnetic field generated around the rotor and an induced current generated in the secondary conductor by the rotating magnetic field.

  In recent years, induction motors using squirrel-cage rotors are sometimes used as drive sources for automobiles, industrial vehicles, and the like. In such applications, downsizing and higher output of induction motors are required. Inevitably, high-speed rotation tends to be required. In order to meet the demand for high-speed rotation, it is necessary to suppress deformation and breakage due to centrifugal force associated with high-speed rotation of the secondary conductor including the conductor bar and the end ring. Specifically, when the squirrel-cage rotor is rotated at a high speed, the centrifugal force accompanying the rotation acts radially outward on the end-entangled ring, etc. It becomes a factor that causes deformation and breakage.

  As an invention made in this regard, a technique described in Patent Document 1 is known. Patent Document 1 describes an invention related to an induction motor, and a rotor of the induction motor includes a conductor bar disposed in a plurality of slots formed in a groove shape on the outer peripheral surface of the rotor core, and a shaft of the rotor core. In the direction end face, it has an end-ring ring (end ring) electrically joined to each conductor bar. And in the rotor of the induction motor described in Patent Document 1, a carbon fiber layer in which carbon fibers are tightly wound around the outer peripheral surface of the rotor core so as to cover the openings in the plurality of slots, and the outer periphery of the carbon fiber layer A SiC layer deposited by CVD is formed on the substrate.

Japanese Patent Laid-Open No. 01-122351

  In the cage rotor in the induction motor described in Patent Document 1 described above, a carbon fiber layer is formed so as to cover an opening of a groove-shaped slot formed on the outer peripheral surface of the rotor core, and a SiC layer is formed on the outer periphery thereof. Thus, when the cage rotor is rotated at a high speed, the centrifugal force acting on the conductor bar in each slot can be counteracted, and damage to the secondary conductor including the conductor bar can be suppressed.

  Thus, according to the invention described in Patent Document 1, it is possible to suppress the damage of the secondary conductor due to the centrifugal force accompanying the high-speed rotation, but a new technique capable of suppressing the damage of the secondary conductor due to the centrifugal force. Is desired. Since damage to the secondary conductor due to centrifugal force is particularly likely to occur at the junction between the end ring and the conductor bar, there is a demand for a technique that can alleviate stress concentration at the junction.

  The present invention relates to an induction motor having a rotor in which a secondary conductor including a plurality of conductor bars and an end ring is arranged, and a stator, and is capable of suppressing damage and deformation of the secondary conductor due to centrifugal force due to high-speed rotation. A simple induction motor.

  An induction motor according to an aspect of the present invention is a rotation shaft that is rotatably arranged, a rotor core that is fixed to the rotation shaft, and is distributed in the circumferential direction of the rotor core around the rotation shaft. A plurality of conductor bars extending in the direction of the rotation axis and an annular shape surrounding the rotation axis outside the end surface of the rotor core in the axial direction of the rotation axis and connected to the plurality of conductor bars A rotor having a secondary conductor including a stator core formed in a cylindrical shape surrounding the periphery of the rotor and having a plurality of slots on an inner peripheral surface thereof; and in the plurality of slots A stator having a coil that is wound and energized to generate a rotating magnetic field, wherein the plurality of conductor bars have a cross-sectional shape perpendicular to the axial direction. An outer diameter side end portion that draws an arc projecting outward in the radial direction on the radially outer side of the rotor core, and the radius of the outer diameter side end portion positioned at the axial end portion of the conductor bar is The conductor bar is formed to be larger than the radius of the end portion on the outer diameter side located at the central portion in the axial direction.

  The induction motor includes a rotor configured as a squirrel-cage rotor and a stator. The rotor is configured to include a rotating shaft, a rotor core, and a secondary conductor including a plurality of conductor bars and an end ring. The stator includes a stator core that is formed in a cylindrical shape surrounding the rotor and a coil that generates a rotating magnetic field. The plurality of conductor bars in the induction motor have an outer diameter side end portion that draws an arc projecting outward in the radial direction on the radially outer side of the rotor core in a cross-sectional shape perpendicular to the axial direction, The radius of the outer diameter side end located at the axial end of the conductor bar is formed larger than the radius of the outer diameter end located at the axial central portion of the conductor bar. That is, the outer diameter side end portion in the axial direction end portion of each conductor bar is joined to the end-ring ring in a wider range. Thereby, according to the said induction motor, the intensity | strength of the junction part of an end ring and each conductor bar can be raised, and the failure | damage of the secondary conductor by the centrifugal force accompanying high speed rotation can be suppressed. In addition, the magnitude of the centrifugal force acting on the secondary conductor as the rotor rotates corresponds to the distance from the rotation axis in the radial direction to the secondary conductor. A larger centrifugal force acts. According to the induction motor, since the radius of the outer diameter side end of each conductor bar is formed large, the strength against centrifugal force acting on the secondary conductor with high-speed rotation can be increased more appropriately.

  An induction motor according to another aspect of the present invention is the induction motor according to claim 1, wherein the plurality of conductor bars have a cross-sectional shape perpendicular to the axial direction inside the rotor core in the radial direction. It has an inner diameter side end portion that draws an arc projecting radially inward, and the radius of the inner diameter side end portion located at the axial direction end portion of the conductor bar is located at the axial center portion of the conductor bar It is characterized by being formed larger than the radius of the inner diameter side end.

  In the induction motor, each of the plurality of conductor bars has an inner diameter side end portion that draws an arc projecting inward in the radial direction on the radial inner side of the rotor core in a cross-sectional shape perpendicular to the axial direction. The radius of the inner diameter side end portion positioned at the axial end portion of the conductor bar is formed larger than the radius of the inner diameter side end portion positioned at the axial center portion of the conductor bar. That is, since the axial end of each conductor bar is joined to the end entanglement ring in a wider range, according to the induction motor, the strength of the joint portion between the end entanglement ring and each conductor bar can be increased, Damage to the secondary conductor due to centrifugal force accompanying high-speed rotation can be suppressed.

  An induction motor according to another aspect of the present invention is the induction motor according to claim 1 or 2, wherein the plurality of conductor bars have a diameter of the rotor core in a cross-sectional shape perpendicular to the axial direction. The inner diameter side end portion located on the inner side in the direction and located at the axial end portion of the conductor bar is larger in diameter than the inner diameter side end portion located at the axial center portion of the conductor bar. It is located inside the direction.

  In the induction motor, the plurality of conductor bars have inner diameter side ends on the radially inner side of the rotor core in a cross-sectional shape perpendicular to the axial direction, and the inner diameter side ends positioned at the axial ends of the conductor bars. The portion is located on the radially inner side of the rotor core with respect to the inner diameter side end located at the axially central portion of the conductor bar. That is, since the axial end of each conductor bar is joined to the end entanglement ring in a wider range, according to the induction motor, the strength of the joint portion between the end entanglement ring and each conductor bar can be increased, Damage to the secondary conductor due to centrifugal force accompanying high-speed rotation can be suppressed. Moreover, since the inner diameter side end portion of the end portion in the axial direction of each conductor bar is located more radially inward, according to the induction motor, the centrifugal force acting on the joint portion between each conductor bar and the end ring is large. The thickness can also be reduced.

  An induction motor according to another aspect of the present invention is the induction motor according to any one of claims 1 to 3, wherein the radius of the outer-diameter side end portion of the conductor bar is equal to that of the conductor bar. It is formed so that it is gradually enlarged as it goes to the axial direction end side.

  In the induction motor, the radius of the end portion on the outer diameter side of the conductor bar is gradually increased toward the end portion in the axial direction of the conductor bar, so that the centrifugal force accompanying high-speed rotation is dispersed. Can act. Thereby, according to the said induction motor, the stress concentration with respect to the secondary conductor accompanying high-speed rotation can be relieved, and the damage of the secondary conductor by centrifugal force can be suppressed.

  An induction motor according to another aspect of the present invention is the induction motor according to any one of claims 1 to 4, wherein a radius of an outer diameter side end portion of the conductor bar is an axis in the stator core. It is characterized in that it is formed larger on the end side in the axial direction than the end face in the direction, and on the outer diameter side end portion located in the central portion in the axial direction of the conductor bar.

  In the induction motor, the radius of the outer diameter side end portion of the conductor bar is larger than the outer diameter side end portion located in the axial center portion of the conductor bar on the axial end portion side than the axial end surface of the stator core. Is also formed large. Here, the secondary conductor closer to the axial end than the axial end face of the stator core does not significantly affect the torque characteristics of the induction motor. Therefore, according to the induction motor, it is possible to suppress the damage / deformation of the secondary conductor caused by the centrifugal force while suppressing the influence on the torque characteristics. And the said induction motor can also respond | correspond to high speed rotation by suppressing the deformation | transformation and damage of the secondary conductor by a centrifugal force.

It is sectional drawing which shows schematic structure of the induction motor which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the II cross section in FIG. It is sectional drawing which shows the structure of the II-II cross section in FIG. It is sectional drawing which shows the structure and positional relationship of each conductor bar in 1st Embodiment. It is a fragmentary sectional view which shows schematic structure of the induction motor which concerns on 2nd Embodiment. It is sectional drawing which shows the structure and positional relationship of each conductor bar in 2nd Embodiment. It is a fragmentary sectional view which shows schematic structure of the induction motor which concerns on 3rd Embodiment. It is sectional drawing which shows the structure and positional relationship of each conductor bar in 3rd Embodiment.

  Hereinafter, an embodiment (first embodiment) in which an induction motor according to the present invention is embodied in an induction motor 1 will be described in detail with reference to the drawings.

(First embodiment)
First, a schematic configuration of the induction motor 1 according to the first embodiment will be described in detail with reference to FIG. The induction motor 1 according to the first embodiment is a squirrel-cage three-phase induction motor, and includes a rotor 10 configured as a squirrel-cage rotor and a stator 50 that generates a rotating magnetic field using a three-phase alternating current. .

  In the induction motor 1, an induction current generated in the secondary conductor 30 (conductor bar 31) of the rotor 10 configured as a squirrel-cage rotor and a rotating magnetic field generated from the stator 50 described later are linked. Rotational force is generated in the rotor 10. And in the said induction motor 1, the rotor 10 and the stator 50 which were mentioned above are accommodated in the case (not shown) inside.

  Next, the configuration of the rotor 10 in the induction motor 1 according to the first embodiment will be described in detail with reference to the drawings. The rotor 10 is configured as a squirrel-cage rotor, and is rotatably supported around the axis C of the rotary shaft 15 on the radially inner side of the stator 50 having a substantially cylindrical shape. As shown in FIG. 1, the rotor 10 includes a cylindrical rotor core 20, a plurality of slots 25 distributed in the circumferential direction of the rotor core 20, and a secondary conductor 30. The secondary conductor 30 includes a conductor bar 31 that is die-cast in the plurality of slots 25 and an annular end ring 35 that is formed so as to short-circuit the plurality of conductor bars 31 at the axial end of the rotor core 20. And. The rotating shaft 15 is rotatably supported by a case (not shown) via a bearing on both axial sides of the induction motor 1.

  The rotor core 20 is formed in a cylindrical shape so as to surround the rotation shaft 15 by laminating a plurality of plates made of electromagnetic steel plates, and is fixed to the rotation shaft 15. Further, the outer peripheral surface of the rotor core 20 is opposed to the above-described inner peripheral surface (surface on the rotating shaft 15 side) of the stator 50 with a space therebetween. Furthermore, a plurality of slots 25 are formed in the rotor core 20 at regular intervals in the circumferential direction of the rotor core 20. That is, the plurality of slots 25 are distributed on the outer peripheral surface side of the rotor core 20 so as to surround the rotating shaft 15. Each slot 25 has a predetermined opening shape and extends so as to penetrate the rotor core 20 in the axial direction. The opening shape of each slot 25, the arrangement of the rotor core 20 and the like will be described in detail later with reference to the drawings.

  As described above, the plurality of conductor bars 31 constituting the secondary conductor 30 are disposed in the plurality of slots 25 distributed in the rotor core 20. The plurality of conductor bars 31 are formed in each slot 25 by die-casting a conductive material such as aluminum and are distributed at equal intervals along the circumferential direction of the rotor core 20.

  Here, since each slot 25 is formed so as to penetrate the rotor core 20 in the axial direction, each conductor bar 31 is disposed so as to extend in the axial direction of the rotor core 20. As shown in FIG. 1, each conductor bar 31 has an axial center portion 31C and an axial end portion 31E. In the first embodiment, the axial end portion 31E is a portion of the conductor bar 31 extending along the axial direction of the rotating shaft 15 that is located closer to the axial end portion side than the axial end surface of the stator core 51. This means that each conductor bar 31 is located at both axial ends. The axial center portion 31 </ b> C is a portion of the conductor bar 31 extending in the axial direction excluding the axial end portion 31 </ b> E and means a portion facing the stator core 51.

  And in the cross section perpendicular | vertical to the axial direction of the rotating shaft 15, the cross-sectional shape of each conductor bar 31 respond | corresponds to the opening shape of each slot 25 (refer FIGS. 2-4). The opening shape of each slot 25 and the cross-sectional shape of each conductor bar 31 will be described later in detail with reference to the drawings.

  And the end ring 35 which comprises the secondary conductor 30 is a member called an end tangle or a short circuit ring, and is formed in the annular | circular shape with aluminum etc. similarly to the conductor bar 31. FIG. The end ring 35 is disposed along both end faces of the rotor core 20 in the axial direction of the rotary shaft 15 and is electrically connected to each conductor bar 31. Thereby, each conductor bar 31 is electrically connected to the pair of end rings 35 and short-circuited.

  Next, the stator 50 constituting the induction motor 1 will be described. The stator 50 is fixed inside the case, and includes a substantially cylindrical stator core 51 and a stator coil 52 wound around the stator core 51. The stator core 51 is configured by laminating a plurality of electromagnetic steel plates. The stator core 51 has a plurality of coil slots (not shown) that are distributed in the circumferential direction and extend in the axial direction. A stator coil 52 made of a conductor is wound around the coil slots. ing.

  In the first embodiment, the stator 50 is configured as a stator used in the induction motor 1 driven by a three-phase alternating current, and includes a three-phase stator coil 52 of U phase, V phase, and W phase. Yes. Therefore, in the induction motor 1, a rotating magnetic field is generated when a three-phase alternating current flows through the stator coil 52 of the stator 50, and the rotor 10 can be rotated about the rotating shaft 15. A portion of each stator coil 52 that protrudes on both axial sides of the stator core 51 is a coil end portion 53.

  Next, specific configurations of the slots 25 and the secondary conductors 30 in the rotor 10 according to the first embodiment will be described in detail with reference to FIGS. 2 to 4 show the cross-sectional shape of the rotor 10 cut along a cross section perpendicular to the rotating shaft 15 of the rotor 10. 2 shows a cross-sectional shape of the II cross section (that is, a cross section related to the axial central portion 31C of the conductor bar 31) in FIG. 1, and shows a cross-sectional shape in the axial central portion of the rotor 10. FIG. 3 shows a cross-sectional shape of the II-II cross section in FIG. 1 (that is, the cross section related to the axial end portion 31E of the conductor bar 31), and the rotor 10 on the axial end portion side of FIG. The cross-sectional shape is shown.

  As shown in FIGS. 2 and 3, the plurality of slots 25 are distributed at regular intervals in the circumferential direction of the rotor core 20 so as to surround the rotating shaft 15. In each slot 25, a conductor bar 31 is provided. Each of them is disposed by die-casting a conductive material such as aluminum into each slot.

  In the cross section perpendicular to the rotating shaft 15, the opening shape of each slot 25 and the cross sectional shape of each conductor bar 31 are each formed in a substantially elongated hole shape whose longitudinal direction extends along the radial direction of the rotor 10. (See FIGS. 2 to 4). And in the opening shape of each slot 25 and the cross-sectional shape of each conductor bar 31, the inner diameter side end located on the radially inner side of the rotor 10 and the outer diameter side end located on the radially outer side of the rotor 10, respectively. The outer diameter side end is formed to draw a larger arc than the inner diameter side end.

  In the following description, the end of each conductor bar 31 positioned on the radially inner side of the rotor 10 in the cross section perpendicular to the rotating shaft 15 is referred to as an inner diameter side end 31I, and is located on the radially outer side of the rotor 10. The end portion of each conductor bar 31 positioned is referred to as an outer diameter side end portion 31O.

  As shown in FIGS. 1 to 3, the outer diameter side end portion 30 </ b> O of each conductor bar 31 has a predetermined dimension from the axial center C of the rotating shaft 15 in both the axial direction central portion 31 </ b> C and the axial direction end portion 31 </ b> E. It is arranged at a separated position. Therefore, the outer diameter side edge of each conductor bar 31 extends linearly along the axial direction of the rotary shaft 15 at a position spaced apart from the axis C of the rotary shaft 15 by a predetermined dimension.

  Subsequently, regarding the induction motor 1 according to the first embodiment, the shape and positional relationship between the axial end portion 31E and the axial center portion 31C of the conductor bar 31 in a cross section perpendicular to the rotation shaft 15 are described with reference to FIG. explain. In FIG. 4, the cross-sectional shape and the like at the axial end portion 31 </ b> E of the conductor bar 31 in the cross section perpendicular to the rotation shaft 15 are indicated by solid lines, and the axial center portion 31 </ b> C of the conductor bar 31 in the cross section perpendicular to the rotation shaft 15. The cross-sectional shape in FIG.

  In the following description, in the cross section perpendicular to the rotating shaft 15, the radius of the arc that forms the outer diameter side end portion 30 </ b> O of the conductor bar 31 is referred to as “outer diameter side radius”. The radius of the arc constituting the part 31I is referred to as “inner diameter side radius”. In the cross section perpendicular to the rotation shaft 15, the dimension in the radial direction of the conductor bar 31 is referred to as “radial dimension”.

  As shown by a broken line in FIG. 4, in the cross section perpendicular to the rotating shaft 15, the axial center portion 31C of the conductor bar 31 is formed to have a predetermined first radial dimension La in the longitudinal direction, The longitudinal direction is arranged along the radial direction of the rotor 10. The outer diameter side end portion 31O in the axial center portion 31C of the conductor bar 31 is formed so as to draw an arc having a predetermined first outer diameter side radius Ra, and the conductor bar 31 has an axial center. The inner diameter side end 31I of the portion 31C is formed so as to draw an arc having a predetermined first inner diameter side radius Da.

  As shown by a solid line in FIG. 4, in the cross section perpendicular to the rotation shaft 15, the axial end portion 31E of the conductor bar 31 has a second radial dimension Lb larger than the first radial dimension La in the longitudinal direction. The longitudinal direction of the rotor 10 is arranged along the radial direction of the rotor 10. The outer diameter side end portion 31O in the axial direction end portion 31E is formed so as to draw an arc having a second outer diameter side radius Rb larger than the first outer diameter side radius Ra. The inner diameter side end 31I of the portion 31E is formed to draw an arc having a second inner diameter side radius Db larger than the first inner diameter side radius Da.

  Accordingly, in each conductor bar 31 arranged in the induction motor 1 according to the first embodiment, the outer diameter side end portion 31O of the axial end portion 31E is the first outer diameter side end portion 31O of the axial direction central portion 31C. It is formed so as to draw an arc having a second outer diameter side radius Rb larger than the first outer diameter side radius Ra, and is joined to the end ring 35 with the axial end portion 31E. That is, since the outer diameter side end portion 31O in the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, according to the induction motor 1, each conductor bar 31 and the end ring 35 are connected. The strength of the joint portion can be increased, and the damage of the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed.

  In addition, the magnitude of the centrifugal force acting on the secondary conductor 30 as the rotor 10 rotates corresponds to the distance from the axis C of the rotary shaft 15 to the secondary conductor 30 in the radial direction. A larger centrifugal force acts on the outer diameter side end portion 31O of 31. According to the induction motor 1, the stress due to the centrifugal force is widely dispersed in the joint portion by forming the radius of the outer diameter side end portion 31 </ b> O in each conductor bar 31 to be large at the axial end portion 31 </ b> E. Can do.

  Furthermore, in each conductor bar 31, the inner diameter side end portion 31I of the axial end portion 31E has a second inner diameter side radius Db larger than the first inner diameter side radius Da of the inner diameter side end portion 31I in the axial center portion 31C. And is joined to the end ring 35 with the axial end portion 31E. That is, the inner diameter side end portion 31I in the axial direction end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range. Therefore, according to the induction motor 1, each conductor bar 31 and the end ring 35 are connected to each other. The strength of the joint portion can be increased, and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed.

  And in each conductor bar 31, axial direction end part 31E is formed so that it may become 2nd radial direction dimension Lb larger than 1st radial direction dimension La in axial direction central part 31C, and the axial direction end part concerned 31E is joined to the end ring 35. That is, since the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, according to the induction motor 1, the strength of the joint portion between each conductor bar 31 and the end ring 35 is increased. It is possible to suppress breakage of the secondary conductor 30 due to centrifugal force accompanying high-speed rotation.

  As shown in FIGS. 1 to 4, the outer diameter side end portion 30 </ b> O of each conductor bar 31 has a predetermined position with respect to the radial direction of the rotor 10 in any of the axial center portion 31 </ b> C and the axial end portion 31 </ b> E. Therefore, the axial end portion 31E is formed to have a second radial dimension Lb larger than the first radial dimension La in the axial central portion 31C. , It can be positioned closer to the inner diameter side of the rotor 10 than the axial central portion 31C. Thereby, according to the said induction motor 1, the centrifugal force which acts on the axial direction edge part 31E with rotation of the rotor 10 can be reduced.

  In the induction motor 1 according to the first embodiment, regarding the cross section perpendicular to the rotary shaft 15, the axial end portions 31 </ b> E having different cross-sectional shapes of the conductor bars 31 are more axial end than the axial end surface of the stator core 51. It is located on the part side. Here, the secondary conductor 30 closer to the axial end than the axial end face of the stator core 51 does not significantly affect the torque characteristics of the induction motor 1. Therefore, according to the induction motor 1, it is possible to suppress the damage / deformation of the secondary conductor 30 due to the centrifugal force while suppressing the influence on the torque characteristics. And the said induction motor 1 can also respond | correspond to high speed rotation by suppressing the deformation | transformation and damage of the secondary conductor 30 by centrifugal force.

  As described above, according to the induction motor 1 according to the first embodiment, the outer diameter side end portion 31O at the axial end portion 31E of each conductor bar 31 is the outer diameter side end portion 31O at the axial center portion 31C. The second outer diameter side radius Ra is larger than the first outer diameter side radius Ra. That is, since the outer diameter side end portion 31O in the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, according to the induction motor 1, each conductor bar 31 and the end ring 35 are connected. The strength of the joint portion can be increased, and the damage of the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed.

  The magnitude of the centrifugal force acting on the secondary conductor 30 as the rotor 10 rotates corresponds to the distance from the rotary shaft 15 to the secondary conductor 30 in the radial direction. A larger centrifugal force acts on the side end portion 31O. According to the induction motor 1, the radius of the outer diameter side end portion 31O in the axial direction end portion 31E of each conductor bar 31 is formed larger than the outer diameter side end portion 31O in the axial direction central portion 31C. The strength against the centrifugal force acting on the joint portion of the secondary conductor 30 with the end ring 35 along with the rotation can be increased more appropriately.

  In the induction motor 1, the inner diameter side end portion 31 </ b> I in the axial end portion 31 </ b> E of each conductor bar 31 is a second larger than the first inner diameter side radius Da related to the inner diameter side end portion 31 </ b> I in the axial center portion 31 </ b> C. It is formed to draw an arc with an inner diameter side radius Db. That is, the inner diameter side end portion 31I in the axial direction end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range. Therefore, according to the induction motor 1, each conductor bar 31 and the end ring 35 are connected to each other. The strength of the joint portion can be increased, and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed.

  Further, in the induction motor 1, the outer diameter side end portion 31O of each conductor bar 31 is located at a predetermined position with respect to the radial direction of the rotor 10 in both the axial center portion 31C and the axial end portion 31E. The axial end portion 31E is formed to have a second radial dimension Lb that is larger than the first radial dimension La in the axial central portion 31C. Thereby, according to the induction motor 1, since the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, the strength of the joint portion between each conductor bar 31 and the end ring 35 is increased. It can be increased and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed. Further, since the inner diameter side end portion 31I of the axial direction end portion 31E in each conductor bar 31 is located more radially inward, according to the induction motor 1, the connection between each conductor bar 31 and the end ring 35 is achieved. The magnitude of the centrifugal force acting on the portion can also be reduced.

  In the induction motor 1, the axial end portions 31 </ b> E having different cross-sectional shapes of the respective conductor bars 31 are located closer to the axial end portion side than the axial end surface of the stator core 51. Here, the secondary conductor 30 positioned closer to the axial end than the axial end face of the stator core 51 does not significantly affect the torque characteristics of the induction motor 1. Therefore, according to the induction motor 1, it is possible to suppress the damage / deformation of the secondary conductor 30 due to the centrifugal force while suppressing the influence on the torque characteristics.

(Second Embodiment)
Next, an embodiment (second embodiment) different from the above-described first embodiment will be described in detail with reference to FIGS. 5 and 6. The induction motor 1 according to the second embodiment has the same basic configuration as the induction motor 1 according to the first embodiment, and the configuration of each slot 25 in the rotor 10 is different. More specifically, in the second embodiment, the shape and configuration of each slot 25 and each conductor bar 31 are different. That is, in the induction motor 1 according to the second embodiment, the configuration of the stator 50 is the same as that of the first embodiment, and thus the description regarding these configurations is omitted.

  As shown in FIG. 5, also in the induction motor 1 according to the second embodiment, the rotor 10 is configured as a squirrel-cage rotor, and the axial center C of the rotary shaft 15 is arranged on the radially inner side of the stator 50 described above. It is supported so that it can rotate around. Also in the rotor 10 according to the second embodiment, a plurality of slots 25 are distributed in the circumferential direction around the rotation shaft 15, and a conductor bar 31 in which a conductive material is die-cast is disposed in each slot 25. Is done.

  Next, regarding the induction motor 1 according to the second embodiment, the shape and positional relationship between the axial end portion 31E and the axial center portion 31C of the conductor bar 31 in a cross section perpendicular to the rotation shaft 15 will be described with reference to FIG. explain. In FIG. 6, regarding the cross section perpendicular to the rotating shaft 15, the cross-sectional shape and the like at the end 31 </ b> E in the axial direction of the conductor bar 31 (the cross-sectional shape in the IV-IV cross section in FIG. 5) are indicated by solid lines. 15, the cross-sectional shape and the like in the axial center portion 31 </ b> C of the conductor bar 31 (the cross-sectional shape in the III-III cross section in FIG. 5) are indicated by broken lines.

  In the cross section perpendicular to the rotation shaft 15 (III-III cross section in FIG. 5), the axial center portion 31C of the conductor bar 31 has a predetermined first radial dimension La as a longitudinal direction, as indicated by a broken line in FIG. It is formed to have in the direction. The outer diameter side end portion 31O in the axial center portion 31C of the conductor bar 31 is formed so as to draw an arc having a predetermined first outer diameter side radius Ra, and the conductor bar 31 has an axial center. The inner diameter side end 31I of the portion 31C is formed so as to draw an arc having a predetermined first inner diameter side radius Da.

  On the other hand, as shown by a solid line in FIG. 6, in the cross section perpendicular to the rotation shaft 15 (IV-IV cross section in FIG. 5), the axial end 31E of the conductor bar 31 according to the second embodiment is A second radial dimension Lb equal to the radial dimension La is formed in the longitudinal direction. The outer diameter side end portion 31O in the axial direction end portion 31E is formed so as to draw an arc having a second outer diameter side radius Rb larger than the first outer diameter side radius Ra. The inner diameter side end 31I of the portion 31E is formed to draw an arc having a second inner diameter side radius Db larger than the first inner diameter side radius Da.

  Therefore, in each conductor bar 31 arranged in the induction motor 1 according to the second embodiment, the outer diameter side end portion 31O of the axial end portion 31E is the first outer diameter side end portion 31O of the axial direction central portion 31C. It is formed so as to draw an arc having a second outer diameter side radius Rb larger than the first outer diameter side radius Ra, and is joined to the end ring 35 with the axial end portion 31E. Therefore, according to the induction motor 1 according to the second embodiment, the outer diameter side end portion 31O in the axial direction end portion 31E of each conductor bar 31 can be joined to the end ring 35 in a wider range. The strength of the joint portion between each conductor bar 31 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed. In addition, according to the induction motor 1 according to the second embodiment, by forming the radius of the outer diameter side end portion 31O of each conductor bar 31 to be large at the axial end portion 31E, the joint portion is subjected to centrifugal force. The accompanying stress can be widely dispersed.

  Further, also in the second embodiment, in each conductor bar 31, the inner diameter side end portion 31I of the axial end portion 31E is larger than the first inner diameter side radius Da of the inner diameter side end portion 31I in the axial central portion 31C. It is formed so as to draw an arc having a radius 2 on the inner diameter side, and is joined to the end ring 35 with the axial end portion 31E. Therefore, according to the induction motor 1 according to the second embodiment, the inner diameter side end portion 31I at the axial end portion 31E of each conductor bar 31 can be joined to the end ring 35 over a wider range. The strength of the joint portion between the bar 31 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed.

  Also in the induction motor 1 according to the second embodiment, the axial end portions 31E having different cross-sectional shapes of the respective conductor bars 31 with respect to the cross section perpendicular to the rotating shaft 15 are axial end portions than the axial end surface of the stator core 51. It is located on the part side. Thereby, also in the induction motor 1 which concerns on 2nd Embodiment, the damage and deformation | transformation of the secondary conductor 30 accompanying a centrifugal force can be suppressed, suppressing the influence with respect to the torque characteristic.

  As described above, also in the induction motor 1 according to the second embodiment, the outer diameter side end portion 31O in the axial direction end portion 31E of each conductor bar 31 is the outer diameter side end portion 31O in the axial direction central portion 31C. The second outer diameter side radius Ra is larger than the first outer diameter side radius Ra and is formed to draw an arc. Therefore, according to the induction motor 1 according to the second embodiment, the outer diameter side end portion 31O in the axial direction end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range. The strength of the joint portion between the end ring 35 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed.

  Also in the induction motor 1 according to the second embodiment, the inner diameter side end 31I at the axial end 31E of each conductor bar 31 is the first inner diameter side radius according to the inner diameter end 31I at the axial center 31C. The second inner diameter side radius Db larger than Da is formed to draw an arc. Therefore, according to the induction motor 1 according to the second embodiment, the inner diameter side end portion 31I at the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, and thus each conductor bar 31 is connected. In addition, the strength of the joined portion of the end ring 35 can be increased, and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed.

  In the induction motor 1 according to the second embodiment, the axial end portions 31 </ b> E having different cross-sectional shapes of the conductor bars 31 are located closer to the axial end portion side than the axial end surface of the stator core 51. Therefore, also in the induction motor 1 according to the second embodiment, the damage / deformation of the secondary conductor 30 due to the centrifugal force can be suppressed while suppressing the influence on the torque characteristics.

(Third embodiment)
Subsequently, an embodiment (third embodiment) different from the first embodiment and the second embodiment described above will be described in detail with reference to FIGS. The induction motor 1 according to the third embodiment has the same basic configuration as the induction motor 1 according to the first embodiment and the second embodiment, and the configuration of the rotor 10 is different. More specifically, in the second embodiment, the shape and configuration of each slot 25 and each conductor bar 31 are different. That is, in the induction motor 1 according to the third embodiment, the configuration of the stator 50 is the same as that of the first embodiment, and thus the description regarding these configurations is omitted.

  As shown in FIG. 7, also in the induction motor 1 according to the third embodiment, the rotor 10 is configured as a squirrel-cage rotor, and the axial center C of the rotary shaft 15 is arranged on the radially inner side of the stator 50 described above. It is supported so that it can rotate around. Also in the rotor 10 according to the third embodiment, a plurality of slots 25 are distributed in the circumferential direction around the rotation shaft 15, and a conductor bar 31 in which a conductive material is die-cast is disposed in each slot 25. Is done.

  Next, regarding the induction motor 1 according to the third embodiment, the shape and positional relationship between the axial end portion 31E and the axial center portion 31C of the conductor bar 31 in a cross section perpendicular to the rotation shaft 15 will be described with reference to FIG. explain. In FIG. 8, regarding the cross section perpendicular to the rotating shaft 15, the cross-sectional shape on the end ring 35 side of the end 31 </ b> E in the axial direction of the conductor bar 31 (the cross-sectional shape in the VII-VII cross section in FIG. 7). , And a cross-sectional shape from the axial center portion 31C of the end portion 31E in the axial direction of the conductor bar 31 (cross-sectional shape in the VI-VI cross section in FIG. 7, etc.) Is indicated by a one-dot chain line. And about the cross section perpendicular | vertical to the rotating shaft 15, the cross-sectional shape etc. in the axial direction center part 31C of the conductor bar 31 (In FIG. 7, the cross-sectional shape in the VV cross section etc.) are shown with the broken line.

  In the cross section perpendicular to the rotation shaft 15 (VV cross section in FIG. 7), the axial central portion 31C of the conductor bar 31 extends a predetermined first radial dimension La as shown by a broken line in FIG. It is formed to have in the direction. The outer diameter side end portion 31O in the axial center portion 31C of the conductor bar 31 is formed so as to draw an arc having a predetermined first outer diameter side radius Ra, and the conductor bar 31 has an axial center. The inner diameter side end 31I of the portion 31C is formed so as to draw an arc having a predetermined first inner diameter side radius Da.

  Further, as shown by a solid line in FIG. 8, in a cross section perpendicular to the rotary shaft 15 and located on the end ring 35 side in the axial end portion 31E (cross section VII-VII in FIG. 7), The end portion 31E in the axial direction of the conductor bar 31 according to the third embodiment is formed so as to have a second radial dimension Lb larger than the first radial dimension La in the longitudinal direction. The outer diameter side end portion 31O in the axial direction end portion 31E according to this cross section is formed to draw an arc having a second outer diameter side radius Rb larger than the first outer diameter side radius Ra. The inner diameter side end 31I of the axial direction end 31E is formed so as to draw an arc having a second inner diameter side radius Db larger than the first inner diameter side radius Da.

  8, a cross section perpendicular to the rotary shaft 15 and located on the axial center portion 31C side in the axial end portion 31E (a VI-VI cross section in FIG. 7), as indicated by a one-dot chain line in FIG. The axial end 31E of the conductor bar 31 according to the third embodiment has a third radial dimension Lc in the longitudinal direction that is larger than the first radial dimension La and smaller than the second radial dimension Lb. Is formed. The outer diameter side end portion 31O of the axial direction end portion 31E in this cross section has a third outer diameter side radius Rc larger than the first outer diameter side radius Ra and smaller than the second outer diameter side radius Rb as a radius. The inner diameter side end 31I of the axial direction end 31E has a third inner diameter side radius Dc that is larger than the first inner diameter side radius Da and smaller than the second inner diameter side radius Db. It is formed so as to draw an arc having a radius.

  Therefore, in each conductor bar 31 arranged in the induction motor 1 according to the third embodiment, the outer diameter side end portion 31O of the axial end portion 31E is directed from the axial central portion 31C toward the axial end portion. It is formed so as to draw an arc with a gradually increasing outer radius, and is joined to the end ring 35 with the axial end portion 31E. Therefore, according to the induction motor 1 according to the third embodiment, the outer diameter side end portion 31O in the axial end portion 31E of each conductor bar 31 can be joined to the end ring 35 in a wider range. The strength of the joint portion between each conductor bar 31 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to centrifugal force accompanying high-speed rotation can be suppressed. In addition, according to the induction motor 1 according to the third embodiment, the radius of the outer diameter side end portion 31O in each conductor bar 31 is gradually increased at the axial end portion 31E, so that the centrifugal portion is centrifuged at the joint portion. The stress accompanying the force can be widely dispersed.

  Furthermore, also in the third embodiment, in each conductor bar 31, the inner diameter side end portion 31I of the axial direction end portion 31E is a circular arc with a gradually increasing inner diameter side radius from the axial direction central portion 31C toward the axial direction end portion. And is joined to the end ring 35 with the axial end portion 31E. Therefore, according to the induction motor 1 according to the third embodiment, the inner diameter side end portion 31I at the axial end portion 31E of each conductor bar 31 can be joined to the end ring 35 over a wider range. The strength of the joint portion between the bar 31 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed. Moreover, according to the induction motor 1 according to the third embodiment, the radial force of the inner diameter side end portion 31I of each conductor bar 31 is gradually increased at the axial end portion 31E, so that the centrifugal force is generated at the joint portion. Can be widely dispersed.

  In each conductor bar 31 according to the third embodiment, the axial end portion 31E is formed such that the radial dimension gradually increases from the axial central portion 31C toward the axial end portion. The end ring 35 is joined with the axial end portion 31E. That is, since the axial end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range, according to the induction motor 1, the strength of the joint portion between each conductor bar 31 and the end ring 35 is increased. It is possible to suppress breakage of the secondary conductor 30 due to centrifugal force accompanying high-speed rotation.

  Further, as shown in FIG. 7, the outer diameter side end portion 31O of each conductor bar 31 is located at a predetermined position in the radial direction of the rotor 10 in both the axial center portion 31C and the axial direction end portion 31E. Therefore, by forming the radial dimension related to the axial end portion 31E so as to gradually increase from the axial central portion 31C toward the axial end portion, the axial end portion 31E is gradually increased. The inner diameter side of the rotor 10 can be positioned. Thereby, according to the said induction motor 1, while the rotor 10 rotates, the centrifugal force which acts on the axial direction edge part 31E can be reduced, and the stress concentration resulting from the said centrifugal force can be relieved.

  Also in the induction motor 1 according to the third embodiment, the axial end portions 31 </ b> E having different cross-sectional shapes of the conductor bars 31 with respect to the cross section perpendicular to the rotating shaft 15 are axial end portions than the axial end surface of the stator core 51. It is located on the part side (see FIG. 7). Thereby, also in the induction motor 1 which concerns on 3rd Embodiment, the damage and deformation | transformation of the secondary conductor 30 accompanying a centrifugal force can be suppressed, suppressing the influence with respect to the torque characteristic.

  As described above, in the induction motor 1 according to the third embodiment, the outer diameter side end portion 31O in the axial end portion 31E of each conductor bar 31 is directed from the axial central portion 31C toward the axial end portion. It is formed so as to draw an arc with a gradually increasing outer radius. Therefore, according to the induction motor 1 according to the third embodiment, the outer diameter side end portion 31O in the axial direction end portion 31E of each conductor bar 31 is joined to the end ring 35 in a wider range. The strength of the joint portion between the end ring 35 and the end ring 35 can be increased, and damage to the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed. In addition, according to the induction motor 1 according to the third embodiment, the joint portion is formed by gradually increasing the outer radius side radius of the outer diameter side end portion 31O in each conductor bar 31 at the axial end portion 31E. The stress accompanying centrifugal force can be widely dispersed.

  In the induction motor 1 according to the third embodiment, the inner diameter side end portion 31I at the axial end portion 31E of each conductor bar 31 is gradually increased from the axial central portion 31C toward the axial end portion. It is formed so as to draw an arc with a radial radius. Therefore, according to the induction motor 1 according to the third embodiment, since the inner diameter side end portion 31I of each conductor bar 31 is joined to the end ring 35 in a wider range, the joining of each conductor bar 31 and the end ring 35 is performed. The strength of the portion can be increased, and damage to the secondary conductor 30 due to the centrifugal force accompanying high-speed rotation can be suppressed. Furthermore, according to the induction motor 1 according to the third embodiment, by gradually forming the inner diameter side radius of the inner diameter side end portion 31I of each conductor bar 31 at the axial end portion 31E, Stress associated with centrifugal force can be widely dispersed.

  Further, in each conductor bar 31 according to the third embodiment, the axial end portion 31E is formed so that the radial dimension gradually increases from the axial central portion 31C toward the axial end portion. The end ring 35 is joined with the axial end portion 31E. That is, according to the induction motor 1, since the axial end portion 31 </ b> E of each conductor bar 31 is joined to the end ring 35 in a wider range, the strength of the joint portion between each conductor bar 31 and the end ring 35 is increased. It is possible to suppress breakage of the secondary conductor 30 due to centrifugal force accompanying high-speed rotation.

  Furthermore, the outer diameter side end portion 30O of each conductor bar 31 is located at a predetermined position in the radial direction of the rotor 10 in both the axial center portion 31C and the axial end portion 31E. The portion 31E can be gradually positioned on the inner diameter side of the rotor 10. As a result, according to the induction motor 1 according to the third embodiment, as the rotor 10 rotates, the centrifugal force acting on the axial end portion 31E is reduced and stress concentration caused by the centrifugal force is reduced. Can do.

  Also in the induction motor 1 according to the third embodiment, the axial end portions 31E having different cross-sectional shapes of the respective conductor bars 31 are located closer to the axial end portion side than the axial end surface of the stator core 51. Therefore, also in the induction motor 1 according to the third embodiment, the damage / deformation of the secondary conductor 30 due to the centrifugal force can be suppressed while suppressing the influence on the torque characteristics.

  Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the shapes of the slots 25 and the conductor bars 31 in the cross section perpendicular to the axial direction of the rotating shaft 15 are the shapes of the rotor 10 as shown in FIGS. 2 to 4, 6, and 8. It is a substantially elongated hole shape having a longitudinal direction along the radial direction, and the outer diameter side end portion is formed to draw a larger arc than the inner diameter side end portion, but is limited to this mode. It is not a thing and a various aspect is employable. The shape of each slot 25 and the conductor bar 31 in the cross section perpendicular to the axial direction of the rotating shaft 15 may be such that the inner diameter side end and the outer diameter side end are formed in an arc shape. It is also possible to adopt a long hole shape in which the radius of the outer diameter side end portion is equal.

  In the above-described embodiments, a method of die-casting a conductor such as aluminum has been adopted as a method of disposing the secondary conductors 30 respectively. Various methods such as a method of joining members formed in a shape (for example, conductor bar 31 and end ring 35 configured as separate members) by welding or the like can be employed.

  Moreover, although the electrically conductive material which comprises the secondary conductor 30 has cited aluminum etc., it is not limited to this aspect. For example, copper, an aluminum alloy, or a copper alloy may be used. The conductor bar 31 and the end ring 35 may be made of different materials.

  Further, in the rotor 10 according to the above-described embodiment, each slot 25 is configured as a closed slot in which the outer peripheral surface side of the rotor core 20 is closed, for example, but is not limited to this mode. Each slot 25 may be an open slot in which the outer peripheral surface side of the rotor core 20 is opened, or a so-called semi-open slot in which the opening width on the outer peripheral surface side of the rotor core 20 is narrower than other portions. Also good.

DESCRIPTION OF SYMBOLS 1 Induction motor 10 Rotor 15 Rotating shaft 20 Rotor core 25 Slot 30 Secondary conductor 31 Conductor bar 31C Axial direction center part 31E Axial direction end part 31I Inner diameter side edge part 31O Outer diameter side edge part 35 End ring 50 Stator 51 Stator core

Claims (5)

A rotating shaft rotatably disposed;
A rotor core fixed to the rotating shaft;
Around the rotating shaft, the plurality of conductor bars distributed in the circumferential direction of the rotor core and extending in the rotating shaft direction, and the rotation on the outer side in the axial direction than the end surface of the rotor core in the axial direction of the rotating shaft A rotor having a secondary conductor that is configured in an annular shape surrounding the periphery of the shaft and includes an end ring connected to the plurality of conductor bars;
A stator core formed in a cylindrical shape surrounding the rotor, and having a plurality of slots on the inner peripheral surface thereof;
A stator having a coil wound in the plurality of slots and generating a rotating magnetic field when energized,
The plurality of conductor bars are:
In the cross-sectional shape perpendicular to the axial direction, on the radially outer side of the rotor core, it has an outer diameter side end portion that draws an arc protruding toward the radially outer side,
A radius of an outer diameter side end portion located at an axial end portion of the conductor bar is formed larger than a radius of an outer diameter side end portion located at an axial center portion of the conductor bar. Induction motor. The induction motor according to claim 1,
The plurality of conductor bars are:
In the cross-sectional shape perpendicular to the axial direction, on the radially inner side of the rotor core, it has an inner diameter side end portion describing an arc protruding toward the radially inner side,
An induction motor characterized in that a radius of an inner diameter side end portion positioned at an axial end portion of the conductor bar is formed larger than a radius of an inner diameter side end portion positioned at an axial center portion of the conductor bar. . An induction motor according to claim 1 or claim 2,
The plurality of conductor bars are:
In a cross-sectional shape perpendicular to the axial direction, the rotor core has an inner diameter side end on the inner side in the radial direction,
An inner diameter side end portion located at an axial end portion of the conductor bar is located on a radially inner side of the rotor core with respect to an inner diameter side end portion located at an axial center portion of the conductor bar. Electric motor. An induction motor according to any one of claims 1 to 3,
The radius of the outer diameter side end of the conductor bar is:
The induction motor is characterized by being gradually formed larger toward the axial end of the conductor bar. An induction motor according to any one of claims 1 to 4,
The radius of the outer diameter side end of the conductor bar is:
An induction motor, wherein the induction motor is formed larger on the axial end portion side than the axial end surface of the stator core than on the outer diameter side end portion located in the axial central portion of the conductor bar.

Images