JP2005168082A - Rotor structure of reluctance motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide rotor structure for a reluctance motor which has high drive torque. <P>SOLUTION: A rotor 20 includes a shaft 100 and a rotor core 200. The rotor core 200 includes a outside diameter part 210 which passes magnetic flux by the rotating magnetic flux of a stator and a circular inside diameter part 220 which is engaged with the shaft 100. The outside diameter part 210 includes a plurality of flux barriers 212 each of which has such a form that it is opened in the periphery of the rotor core 200 and widened in the circumferential direction on the inside as compared with the outside in the radial direction, and a magnetic path 214 which has a magnetic path that passes the magnetic flux by the rotating magnetic flux of the stator and is a section sandwiched by adjacent flux barriers 212. The magnetic path 214 and the inside diameter part 220 are coupled with each other by a bridge 222 where magnetism is saturated by the magnetic flux flowing toward the center of the rotor 20 from the magnetic path 214. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotor structure of a reluctance motor, and more particularly, to a rotor structure of a reluctance motor having a stator and a rotor disposed on an inner periphery of the stator via an air gap.

  Conventionally, a reluctance motor having a rotor that rotates by forming a magnetic pole by a rotating magnetic field generated by a stator is known. It is known that the torque of the reluctance motor is proportional to the difference (Ld−Lq) between the d-axis inductance Ld representing the ease of passing the d-axis magnetic flux and the q-axis inductance Lq representing the ease of passing the q-axis magnetic flux. ing. In order to increase the difference between the d-axis inductance Ld and the q-axis inductance Lq, a technique in which a flux barrier is provided on the outer peripheral portion of the rotor has been proposed.

  Japanese Patent Laying-Open No. 2001-231229 (Patent Document 1) discloses a reluctance motor that can sufficiently increase torque and rotate at high speed. The reluctance motor described in Patent Document 1 has a stator that generates an alternating magnetic field by receiving an AC signal, and a plurality of magnetic paths that are arranged on the inner periphery of the stator via an air gap and allow magnetic flux generated by the stator to pass through. And a rotor that forms magnetic poles by magnetic flux passing through a plurality of magnetic paths. The rotor has a flux barrier that opens to the outer periphery of the magnetic pole portion.

According to the reluctance motor disclosed in this publication, since the magnetic pole part of the rotor has a plurality of magnetic paths that allow the magnetic flux associated with the rotating magnetic field generated by the stator to pass, the reluctance motor is provided with a flux barrier that opens to the outer periphery. The q-axis magnetic flux bypasses the flux barrier and passes through the rotor, increasing the magnetic resistance to the q-axis magnetic flux and reducing the q-axis inductance Lq, thereby sufficiently increasing the torque.
JP 2001-231229 A

  However, the reluctance motor described in Patent Document 1 has a problem that magnetic flux flows toward the center side in the radial direction of the rotor, and an increase in the q-axis inductance Lq cannot be sufficiently suppressed. This will be described in detail with reference to FIG. The conventional reluctance motor includes a stator 300 and a rotor 400. The rotor 400 includes a shaft 410 and a rotor core 420 fitted to the shaft 410. When an alternating current (for example, a three-phase alternating current) is passed through the stator 300, the stator 300 generates a rotating magnetic field. Magnetic flux flows from the stator 300 to the rotor core 420 fitted to the shaft 410 by the rotating magnetic field of the stator 300. The d-axis magnetic flux flowing through the rotor core 420 flows in an arc shape through the outer diameter portion 422 of the rotor core 420 as indicated by a solid line. The q-axis magnetic flux flowing through the rotor core 420 flows through the inner diameter portion 424 of the rotor core 420 as indicated by a broken line. In order to increase the magnetic resistance of the inner diameter portion 424 of the rotor core 420, the thickness (radial thickness) of the inner diameter portion 424 may be reduced. However, if the thickness is reduced, the rigidity of the rotor core 420 is reduced. There is a limit to reducing the wall thickness. For this reason, the q-axis inductance Lq cannot be made sufficiently small.

  Further, the q-axis magnetic flux flowing through the rotor core 420 flows through the shaft 410 in addition to the inner diameter portion 424, as indicated by a one-dot chain line. For this reason, q-axis magnetic flux increases and q-axis inductance Lq will increase. As the q-axis magnetic flux increases, the d-axis magnetic flux decreases accordingly, and the d-axis inductance Ld decreases.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a rotor structure of a reluctance motor capable of generating a high torque.

  A rotor structure of a reluctance motor according to a first invention includes a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on an inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough. The rotor structure further includes a shaft that is rotatably supported, an annular inner diameter portion that is fitted to the shaft so as to surround the outer periphery of the shaft, and a magnetic flux generated by the stator that is provided radially outside the inner diameter portion. Is provided between the outer diameter portion and the inner diameter portion and the outer diameter portion, and is formed so as to connect the inner diameter portion and the outer diameter portion, and the magnetic flux flowing from the outer diameter portion to the center side of the rotor And a bridge portion formed so as to be saturated.

  According to the first invention, the annular inner diameter portion is fitted to the shaft so as to surround the outer periphery of the shaft that is rotatably supported. An outer diameter portion that allows the magnetic flux generated by the stator to pass therethrough is provided outside the inner diameter portion in the radial direction. The inner diameter portion and the outer diameter portion are located between the inner diameter portion and the outer diameter portion, and are connected by a bridge portion where magnetic flux flowing from the outer diameter portion to the center side of the rotor is saturated. As a result, the magnetic flux that flows from the outer diameter portion to the center side of the rotor is saturated in the bridge portion (the bridge portion is magnetically saturated), so that the magnetic flux that flows from the outer diameter portion to the center side of the rotor is limited. The magnetic flux flowing through is limited. As a result, it is possible to provide a rotor structure of a reluctance motor that can suppress a decrease in d-axis magnetic flux and an increase in q-axis magnetic flux and generate high torque.

  In the rotor structure of the reluctance motor according to the second invention, in addition to the configuration of the first invention, the outer diameter portion includes a plurality of gaps opened on the outer periphery of the outer diameter portion. Each air gap is provided so as to have a predetermined interval with an adjacent air gap, and the shape of each air gap is formed so that the inner side expands in the circumferential direction as compared to the outer side in the radial direction in the rotor cross section. Has been. A bridge part is a part which connects an inner diameter part and an outer diameter part in the position where the space | interval is the narrowest among adjacent space | gap.

  According to the second invention, the bridge portion is open between the outer circumferences, and is between the gaps formed so that the inner side extends in the circumferential direction as compared with the outer side in the radial direction in the rotor cross section, and the gap is the narrowest. It is the part which has connected the inner diameter part and the outer diameter part at the position. For this reason, the bridge portion has a narrow width in the radial direction, and is easily magnetically saturated. As a result, a decrease in d-axis magnetic flux and an increase in q-axis magnetic flux are suppressed.

  In the rotor structure of the reluctance motor according to the third aspect of the invention, in addition to the configuration of the second aspect of the invention, the outer diameter portion is provided with an arc shape protruding toward the center of the rotor provided between the adjacent gaps. Has a slit. Each gap is formed to have an outer shape along the slit. The bridge portion is formed so as to connect the inner diameter portion and the outer diameter portion on a straight line connecting the apex of the slit and the center of the rotor.

  According to the third invention, an arc-shaped slit protruding toward the center of the rotor is provided between the adjacent gaps of the outer diameter portion. The portion sandwiched between the gaps and provided with the slit becomes a magnetic path portion through which the magnetic flux by the stator passes. The magnetic flux passes along the stator in an arc shape. Since each air gap has an outer shape along the slit, the inner surface of the magnetic path portion (the outer shape of the air gap) has an arc shape protruding toward the center of the rotor. The bridge portion connects the inner diameter portion and the outer diameter portion on a straight line connecting the apex of the slit and the center of the rotor. Therefore, the bridge portion connects the inner diameter portion and the outer diameter portion at the top of the inner surface of the magnetic path portion. Thereby, an outer diameter part (magnetic path part) is supported in a centrifugal force direction by a bridge part. As a result, a decrease in d-axis magnetic flux and an increase in q-axis magnetic flux can be suppressed, and the outer diameter portion can be stably supported during rotation of the rotor.

  A rotor structure of a reluctance motor according to a fourth aspect of the present invention is a reluctance having a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on the inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough. It is a rotor structure of a motor. This rotor structure is further provided between a shaft rotatably supported, a radially outer side than the shaft, an outer diameter part through which a magnetic flux by the stator passes, and an outer diameter part. And a coupling portion that couples the diameter portion to the shaft and has a lower magnetic permeability than the outer diameter portion.

  According to the fourth aspect of the present invention, the outer diameter portion through which the magnetic flux by the stator passes is provided on the outer side in the radial direction from the shaft supported rotatably. The outer diameter portion is provided between the shaft and the outer diameter portion, and is coupled to the shaft by a coupling portion having a lower magnetic permeability than the outer diameter portion. For this reason, the magnetic flux that passes through the outer diameter portion hardly passes through the coupling portion, and leakage of the magnetic flux from the outer diameter portion is suppressed. As a result, it is possible to provide a rotor structure of a reluctance motor that can suppress a decrease in d-axis magnetic flux and an increase in q-axis magnetic flux and generate high torque.

  The reluctance motor rotor structure according to the fifth invention is an annular ring in which the coupling portion is formed of a nonmagnetic material and is fitted to the shaft so as to surround the outer periphery of the shaft in addition to the configuration of the fourth invention. Part.

  According to the fifth invention, the coupling portion is an annular ring portion that is formed of a nonmagnetic material and is fitted to the shaft so as to surround the outer periphery of the shaft. Thereby, the magnetic flux which passes an outer diameter part cannot pass a ring part, but can further suppress the leakage of the magnetic flux from an outer diameter part.

  A rotor structure of a reluctance motor according to a sixth aspect of the present invention is a reluctance having a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on the inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough. It is a rotor structure of a motor. The rotor structure is further provided on the outer periphery of the rotor, and is provided with an outer diameter part through which the magnetic flux from the stator passes, and is provided radially inside the outer diameter part, and is rotatably supported. And a shaft having a lower magnetic permeability.

  According to the sixth invention, the shaft having a lower magnetic permeability than the outer diameter portion is rotatably supported on the inner side in the radial direction than the outer diameter portion through which the magnetic flux by the stator passes. As a result, the magnetic flux passing through the outer diameter portion is difficult to pass through the shaft, and leakage of the magnetic flux from the outer diameter portion is suppressed. As a result, it is possible to provide a rotor structure of a reluctance motor that can suppress a decrease in d-axis magnetic flux and an increase in q-axis magnetic flux and generate high torque.

  In the rotor structure of the reluctance motor according to the seventh invention, in addition to the configuration of the sixth invention, the shaft is formed of a nonmagnetic material.

  According to the seventh invention, the shaft is made of a nonmagnetic material. Thereby, the magnetic flux which passes an outer diameter part cannot pass a shaft, and can further suppress the leakage of the magnetic flux from an outer diameter part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a first embodiment of the present invention is applied will be described with reference to FIG.

  The reluctance motor includes a stator 10 housed in an outer case (not shown) and a rotor 20 housed radially inward of the stator. The rotor 20 includes a shaft 100 that is rotatably supported by an exterior case via a ball bearing, and a rotor core 200 that is fitted to the shaft 100. This reluctance motor is a three-phase AC motor.

  The shaft 100, the rotor core 200, and the stator 10 are made of a magnetic material such as iron. When an alternating current is passed through the stator 10, the stator 10 generates a rotating magnetic field. Magnetic flux generated by the rotating magnetic field generated by the stator 10 passes through the rotor core 200. When the magnetic flux passes through the rotor core 200, the rotor core 200 forms a magnetic pole. Thereby, the rotor core 200 is rotated and the shaft 100 is rotated. The operating principle of the reluctance motor may be a well-known general technique, and therefore, detailed description thereof will not be repeated here.

  With reference to FIG. 2, the rotor structure of the reluctance motor according to the present embodiment will be further described. The rotor core 200 includes an outer diameter portion 210 that allows a magnetic flux generated by the rotating magnetic field of the stator 10 to pass through, an annular inner diameter portion 220 that is fitted to the shaft 100 so as to surround the shaft 100, an outer diameter portion 210, and an inner diameter portion 220. And a plurality of bridges 222 that connect the outer diameter portion 210 and the inner diameter portion 220.

  The outer diameter portion 210 opens on the outer peripheral surface of the rotor core 200 and is sandwiched between a plurality of flux barriers (air gaps) 212 having a shape that increases in width toward the center of the rotor 20 and adjacent flux barriers 212. And includes a magnetic path portion 214 having a magnetic path through which the magnetic flux generated by the rotating magnetic field of the stator 10 passes. In the magnetic path portion 214, arc-shaped slits 216 (A), slits 216 (B), and slits 216 that extend in parallel with the axial direction of the shaft 100 (perpendicular to the paper surface) and project toward the center of the rotor 20. (C) is provided. The outer shape of each flux barrier 212 is an arc shape along the slit 216 (A). Therefore, the inner surface 215 of the magnetic path portion 214 has an arc shape protruding toward the center of the rotor 20. Each flux barrier 212 is formed so that the inner side extends in the circumferential direction as compared with the outer side in the radial direction.

  Magnetic flux due to the rotating magnetic field of the stator 10 flows avoiding each slit. That is, between each slit and between the slit 216 (A) and the flux barrier 212 is a magnetic path through which the d-axis magnetic flux passes. Both ends of this magnetic path become magnetic poles by the rotating magnetic field of the stator 10. Therefore, the opening of the flux barrier 212 is located between adjacent magnetic poles.

  The bridge 222 is an outer peripheral surface of the inner diameter portion 220 so as to connect the outer diameter portion 210 (magnetic path portion 214) and the inner diameter portion 220 on a straight line connecting the apex of the slit 216 (A) and the center of the rotor 20. The same number of magnetic path portions 214 are arranged at predetermined intervals in the circumferential direction, and extend parallel to the radial direction of the rotor core 200, that is, parallel to the centrifugal force direction of the rotor core 200. ing. Therefore, each bridge 222 connects the outer diameter portion 210 (magnetic path portion 214) and the inner diameter portion 220 at the top of the inner surface 215 of each magnetic path portion 214. The bridge 222 connects the outer diameter portion 210 (magnetic path portion 214) and the inner diameter portion 220 at the narrowest position among the intervals between adjacent flux barriers 212.

  With reference to FIG. 3, an explanation will be given of the action that is manifested by the structural features of the reluctance motor according to the present embodiment based on the above configuration.

  When an alternating current (for example, a three-phase alternating current) is passed through the stator 10, the stator 10 generates a rotating magnetic field. Magnetic flux generated by the rotating magnetic field generated by the stator 10 flows from the teeth of the stator 10 to the rotor core 200 through the air gap. The d-axis magnetic flux flows in the direction of the solid arrow between the slits provided in the magnetic path portion 214 of the rotor core 200 and between the slit 216 (A) and the flux barrier 212. On the other hand, a part of the d-axis magnetic flux leaks from the magnetic path portion 214 through the bridge 222 to the center side of the rotor 20 as indicated by a broken arrow. When the magnetic flux flows in the bridge 222, the magnetic flux is saturated in the bridge 222 (the bridge 222 is magnetically saturated). When the bridge 222 is magnetically saturated, the magnetic flux that passes through the bridge 222 and leaks to the center side of the rotor 20 is limited. The magnetic flux that has passed through the bridge 222 flows through the inner diameter portion 220 and the shaft 100 as a q-axis magnetic flux, as indicated by an alternate long and short dash line arrow. Since the bridge 222 is magnetically saturated, no magnetic flux greater than the magnetic flux that is magnetically saturated by the bridge 222 does not flow through the inner diameter portion 220 and the shaft 100. Thereby, the q-axis magnetic flux is limited, the leakage of the d-axis magnetic flux flowing through the magnetic path portion 214 of the rotor core 200 is limited, and the decrease in the d-axis inductance Ld and the increase in the q-axis inductance Lq are suppressed.

  Further, since the magnetic flux passing through the bridge 222 is limited, the magnetic flux leaking to the inner diameter portion 220 is also limited. Therefore, even if the radial thickness of the inner diameter portion 220 is increased, the influence on the increase in the q-axis inductance Lq is small. As a result, the radial thickness of the inner diameter portion 220 can be increased and the rigidity of the rotor core 200 can be increased.

  When the rotor 20 rotates, a centrifugal force is applied to each magnetic path portion 214. When a centrifugal force is applied to the magnetic path part 214, the magnetic path part 214 is connected to the inner diameter part 20 at the top of the inner surface 215 protruding toward the center of the rotor 20. Supported in the force direction. For this reason, the magnetic path portion 214 can be stably supported by the bridge 222 during the rotation of the rotor 20.

  As described above, in the rotor structure of the reluctance motor according to the present embodiment, the outer diameter portion and the inner diameter portion of the rotor are connected by the bridge. Magnetic flux that leaks from the outer diameter portion to the inner diameter portion passes through the bridge. As a result, the bridge is magnetically saturated. As a result, the magnetic flux leaking from the outer diameter to the inner diameter side can be limited, and the decrease in the d-axis inductance Ld and the increase in the q-axis inductance Lq can be suppressed.

<Second Embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a second embodiment of the present invention is applied will be described with reference to FIG. In the first embodiment described above, the bridge connects the outer diameter portion and the inner diameter portion at the top of the inner surface of each magnetic path portion, but in this embodiment, a plurality of bridges are provided, An inter-bridge slit 228 is provided near the top of the inner surface of the magnetic path portion. Other hardware configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  The outer diameter portion 210 (magnetic path portion 214) and the inner diameter portion 220 are connected to one magnetic path portion 214 by two bridges 226 (A) and a bridge 226 (B). An inter-bridge slit 228 is provided between the bridge 226 (A) and the bridge 226 (B) near the top of the inner surface of the magnetic path portion 214.

  Even if comprised in this way, the effect similar to the above-mentioned 1st Embodiment can be acquired.

<Third Embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a third embodiment of the present invention is applied will be described with reference to FIG. In the first embodiment described above, the magnetic path of the magnetic flux passing through the outer diameter portion is divided into the radially inner magnetic path and the radially outer magnetic path by the slit. In this embodiment, the radially outer magnetic path and the inner magnetic path are connected. Other hardware configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  As shown in FIG. 5, a magnetic path 217 (A) positioned radially inward of the slit 216 (A) positioned radially inward, and a magnetic path 217 (B) positioned radially outward Are connected by a bridge 218 between magnetic paths. The bridge 218 between magnetic paths is located on the extension line of the bridge 222.

  Based on the above configuration, an operation that is manifested by structural features of the reluctance motor according to the present embodiment will be described.

  When an alternating current (for example, a three-phase alternating current) is passed through the stator 10, the stator 10 generates a rotating magnetic field. Magnetic flux generated by the rotating magnetic field generated by the stator 10 flows through the rotor core 200. When magnetic flux flows through the rotor core 200, the rotor core 200 rotates. When the rotor core 200 rotates, a centrifugal force is applied to each magnetic path portion 214. The centrifugal force of the magnetic path portion 214 acts in a direction to separate the magnetic path 217 (A) and the magnetic path 217 (B), and becomes a force that deforms the magnetic path portion 214. Here, the magnetic path 217 (A) and the magnetic path 217 (B) are connected by the inter-magnetic path bridge 218 located on the extension line of the bridge 222. Thereby, the bridge 218 between magnetic paths connects the magnetic path 217 (A) and the magnetic path 217 (B) in the centrifugal force direction. Therefore, it is possible to suppress the magnetic path 217 (A) and the magnetic path 217 (B) from being separated and the magnetic path portion 214 from being deformed.

  As described above, in the rotor structure of the reluctance motor according to the present embodiment, the magnetic path positioned radially inward and the magnetic path positioned radially outward are connected by the inter-magnetic path bridge. Yes. Thereby, it can suppress that the magnetic path located in a radial direction inner side and the magnetic path located in a radial direction outward are pulled apart by a centrifugal force, and a magnetic path part deform | transforms.

<Fourth embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a fourth embodiment of the present invention is applied will be described with reference to FIG. In the first embodiment described above, the inner diameter portion of the rotor core 200 is fitted to the shaft 100, and the outer diameter portion and the inner diameter portion are connected by a bridge. However, in the present embodiment, the shaft 100 is connected to the shaft 100. The outer diameter part is fixed to the shaft by fitting the ring 230 and holding the outer diameter part on the ring 230. Other hardware configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  An annular ring 230 is fitted to the shaft 100 so as to surround the shaft 100. Ring 230 is formed of a nonmagnetic material such as stainless steel. The ring 230 is provided with a plurality of holding portions 232 arranged along the circumferential direction at predetermined intervals and extending in parallel with the axial direction of the shaft 100. By inserting the magnetic path portion 214 between the adjacent holding portions 232, the outer diameter portion 210 (magnetic path portion 214) is held by the ring 230 and fixed to the shaft. Note that the ring 230 may be formed of a material having a lower magnetic permeability than the outer diameter portion 210 instead of the nonmagnetic material.

  Based on the above configuration, an operation that is manifested by structural features of the reluctance motor according to the present embodiment will be described.

  When an alternating current (for example, a three-phase alternating current) is passed through the stator 10, the stator 10 generates a rotating magnetic field. Magnetic flux generated by the rotating magnetic field generated by the stator 10 flows from the teeth of the stator 10 to the outer diameter portion 210 of the rotor core 200. Here, since the outer diameter portion 210 is fixed to the shaft 100 by a ring 230 formed of a nonmagnetic material, the magnetic flux flowing through the outer diameter portion 210 cannot pass through the ring 230 and is located on the center side of the rotor 20. Does not flow. Thereby, the leakage of the d-axis magnetic flux flowing through the outer diameter portion 210 is suppressed, and the decrease of the d-axis inductance Ld and the increase of the q-axis inductance Lq are suppressed.

  As described above, in the rotor structure of the reluctance motor according to the present embodiment, the ring formed of the nonmagnetic material is fitted to the shaft. The outer diameter portion is held by the ring. Thereby, the leakage of the d-axis magnetic flux flowing through the outer diameter portion is suppressed. As a result, a decrease in d-axis inductance Ld and an increase in q-axis inductance Lq can be suppressed.

<Fifth embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a fifth embodiment of the present invention is applied will be described with reference to FIG. In the above-described fourth embodiment, the ring formed of the non-magnetic material is fitted to the shaft formed of the magnetic material. However, in this embodiment, the shaft and the ring are It is formed integrally using a magnetic material. Other hardware configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  As shown in FIG. 7, the shaft 110 and the ring 230 are integrally formed. The shaft 110 and the ring 230 are made of a nonmagnetic material. Even if comprised in this way, the effect similar to the above-mentioned 4th Embodiment can be acquired. The shaft 110 and the ring 230 may be formed of a material having a lower magnetic permeability than the outer diameter portion 210 instead of the nonmagnetic material.

<Sixth Embodiment>
A reluctance motor to which a rotor structure of a reluctance motor according to a sixth embodiment of the present invention is applied will be described with reference to FIG. In the first embodiment described above, the shaft is formed of a magnetic material, but in the present embodiment, the shaft is formed of a nonmagnetic material. Moreover, the outer diameter part and the inner diameter part are directly connected without a bridge. Other hardware configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  The reluctance motor according to the sixth embodiment of the present invention includes a shaft 120 formed of a nonmagnetic material, and a rotor core 240 fixed to the shaft 120. The rotor core 240 includes an annular inner diameter portion 242 fitted to the shaft 120 and an outer diameter portion 244 directly connected to the inner diameter portion 242. Note that the shaft 120 may be formed of a material having a lower magnetic permeability than the outer diameter portion 244 instead of the nonmagnetic material.

  Based on the above configuration, an operation that is manifested by structural features of the reluctance motor according to the present embodiment will be described.

  When an alternating current (for example, a three-phase alternating current) is passed through the stator 10, the stator 10 generates a rotating magnetic field. Magnetic flux generated by the rotating magnetic field generated by the stator 10 flows from the teeth of the stator 10 to the rotor core 240. Part of the magnetic flux flowing through the rotor core 240 leaks from the outer diameter portion 244 to the inner diameter portion 242. Here, since the shaft 120 is made of a nonmagnetic material, the magnetic flux leaking to the inner diameter portion 242 does not pass through the shaft 120. Thereby, the magnetic flux flowing through the outer diameter portion 244 of the rotor core 200 leaks only to the inner diameter portion 242. As a result, leakage of magnetic flux flowing through the outer diameter portion 244 of the rotor core 200 is suppressed, and a decrease in the d-axis inductance Ld and an increase in the q-axis inductance Lq are suppressed.

  As described above, in the rotor structure of the reluctance motor according to the present embodiment, the shaft is formed of the nonmagnetic material. Thereby, leakage of the magnetic flux flowing through the outer diameter part of the rotor core is suppressed, and a decrease in d-axis inductance Ld and an increase in q-axis inductance Lq are suppressed. As a result, a reduction in torque of the reluctance motor can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 1st Embodiment is applied. It is the enlarged view to which the rotor core of the reluctance motor which concerns on 1st Embodiment was expanded. It is a figure which shows the flow of magnetic flux. It is the enlarged view to which the rotor core of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 2nd Embodiment was applied was expanded. It is the enlarged view to which the rotor core of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 3rd Embodiment was applied was expanded. It is the enlarged view to which the rotor core of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 4th Embodiment was applied was expanded. It is the enlarged view to which the rotor core of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 5th Embodiment was applied was expanded. It is the enlarged view to which the rotor core of the reluctance motor to which the rotor structure of the reluctance motor which concerns on 6th Embodiment was applied was expanded. It is sectional drawing which shows the conventional reluctance motor.

Explanation of symbols

  10 stator, 20 rotor, 100, 110, 120 shaft, 200 rotor core, 210 outer diameter part, 212 flux barrier, 214 magnetic path part, 220 inner diameter part, 222, 226 bridge, 230 ring, 232 holding part, 240 rotor core, 242 Inner diameter part, 244 outer diameter part.

Claims (7)

A rotor structure of a reluctance motor having a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on an inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough,
A shaft rotatably supported;
An annular inner diameter portion fitted to the shaft so as to surround the outer periphery of the shaft;
An outer diameter portion that is provided on the outer side in the radial direction than the inner diameter portion, and allows a magnetic flux by the stator to pass through;
Provided between the inner diameter part and the outer diameter part and formed to connect the inner diameter part and the outer diameter part, and the magnetic flux flowing from the outer diameter part to the center side of the rotor is saturated. A rotor structure of a reluctance motor, including a bridge portion formed as described above. The outer diameter portion includes a plurality of voids opened on the outer periphery of the outer diameter portion, and each of the voids is provided to have a predetermined interval with an adjacent void, and the shape of each of the voids Is formed so that the inner side extends in the circumferential direction compared to the outer side in the radial direction in the rotor cross section,
2. The rotor structure of a reluctance motor according to claim 1, wherein the bridge portion is a portion that connects the inner diameter portion and the outer diameter portion at a position where an interval between adjacent gaps is the narrowest. The outer diameter portion has an arc-shaped slit provided between adjacent gaps and projecting toward the center of the rotor, and each gap is formed to have an outer shape along the slit. And
3. The rotor of a reluctance motor according to claim 2, wherein the bridge portion is formed so as to connect the inner diameter portion and the outer diameter portion on a straight line connecting the apex of the slit and the center of the rotor. Construction. A rotor structure of a reluctance motor having a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on an inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough,
A shaft rotatably supported;
An outer diameter portion that is provided on the outer side in the radial direction from the shaft, and allows magnetic flux from the stator to pass through;
A rotor structure of a reluctance motor, comprising: a coupling portion that is provided between the shaft and the outer diameter portion, couples the outer diameter portion to the shaft, and has a lower magnetic permeability than the outer diameter portion.   5. The rotor structure of a reluctance motor according to claim 4, wherein the coupling portion is an annular ring portion that is formed of a nonmagnetic material and is fitted to the shaft so as to surround the outer periphery of the shaft. A rotor structure of a reluctance motor having a stator that generates a rotating magnetic field in response to an AC signal, and a rotor that is disposed on an inner periphery of the stator via an air gap and allows a magnetic flux from the stator to pass therethrough,
An outer diameter portion that is provided on an outer peripheral portion of the rotor and allows a magnetic flux from the stator to pass therethrough;
A rotor structure of a reluctance motor, including a shaft that is provided radially inward of the outer diameter portion, is rotatably supported, and has a lower magnetic permeability than the outer diameter portion.   The rotor structure of a reluctance motor according to claim 6, wherein the shaft is made of a nonmagnetic material.

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