JP6178781B2 - Cage type induction motor and rotor for cage type induction motor - Google Patents

Description

  The present invention relates to a cage induction motor and a rotor thereof.

  A conventional typical squirrel-cage induction motor includes a rotor that can rotate around a rotation axis, and a stator that is disposed so as to surround a radially outer side of the rotor.

  The rotor includes a plurality of rotor cores that are formed in a substantially cylindrical shape, a rotor shaft, and a plurality of rotor cores that pass through the vicinity of the outer periphery of the rotor core in the axial direction and are spaced apart from each other in the circumferential direction. A conductor bar, and a short-circuit ring that electrically shorts the axial ends of the conductor bar by connecting them in the circumferential direction. The short ring must be made of a material having high conductivity, and is usually made of copper, aluminum, or the like.

  A material with high electrical conductivity is usually not high in strength. Therefore, a technology is known in which a retaining ring using a high-strength material such as steel is placed outside the short-circuiting ring and the centrifugal force applied to the short-circuiting ring is received by the retaining ring. (Patent Document 1). The retaining ring is particularly important in an electric motor in which a large centrifugal force is applied by high-speed rotation.

JP-A-6-197504

  The conventional short-circuit ring and holding ring are arranged at positions away from the axial end of the iron core, and the conductive bar protrudes in the axial direction from the axial end of the iron core and is connected to the short-circuit ring.

  In the conventional configuration, the structure of the end portion of the conductive bar is complicated, and the manufacturing cost is increased.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a squirrel-cage induction motor that has a simple structure and can withstand high-speed rotation.

In order to solve the above problems, a squirrel-cage induction motor according to the present invention includes a rotor that can rotate around a rotation axis, and a stator that is disposed so as to surround the outer side in the radial direction of the rotor. A squirrel-cage induction motor, wherein the rotor is provided on a rotor core part mainly composed of a magnetic material formed in a substantially cylindrical shape with the rotation axis as an axis, and on both sides in the axial direction of the rotor core part. The rotor core is disposed coaxially with the axis of the rotor core, has a diameter smaller than that of the rotor core, and is integrated with the rotor core, and the rotor core is axial. And a plurality of conductor bars arranged in the circumferential direction with a space therebetween, and axial ends of the conductor bars are connected in the circumferential direction to electrically connect the axial ends of the conductor bars. A short-circuit ring for short-circuiting, along the outer periphery of the axial end of the rotor core. An annular projecting portion projecting in the axial direction is formed, the outer surface of the short-circuit ring is supported by the inner surface of the projecting portion, and the axial end of the rotor core is centered on the rotational axis An end groove that extends in a ring shape and has a radial width larger than the radial width of the short-circuiting ring is formed, and the side of the end groove that is far from the rotation axis forms the projecting portion, and the short-circuiting ring is the end portion. Embedded in and fixed to the end groove along the outer periphery of the groove, and the edge on the radially inner side of the end groove is on the inner side of the short-circuit ring, and the edge on the radially inner side of the end groove; An annular indentation space is formed between the inner surface of the short-circuit ring.

The rotor for a cage induction motor according to the present invention is a rotor for a cage induction motor that is rotatably supported in a stator, and is a magnetic material formed in a substantially columnar shape with a rotation axis as an axis. A rotor core portion made of a main material, and arranged coaxially with the axis of the rotor core portion on both sides in the axial direction of the rotor core portion, and having a smaller diameter than the rotor core portion, A rotor shaft portion integrally formed with the rotor core portion, a plurality of conductor bars that pass through the rotor core portion in the axial direction and are spaced apart from each other in the circumferential direction, and an axial end of the conductor bar A short-circuit ring that connects the parts in the circumferential direction and electrically short-circuits the axial ends of the conductor bar, and in the axial direction along the outer periphery of the axial end of the rotor core part. A projecting annular projecting portion is formed, and the outer surface of the short-circuiting ring is an inner portion of the projecting portion. Be supported in terms, the radial width extending annularly about the axis of rotation is formed larger end groove than the radial width of the short ring at an axial end of the rotor core section this The side of the end groove that is far from the rotation axis constitutes the overhanging portion, and the short-circuit ring is embedded and fixed in the end groove along the outer periphery of the end groove, and the radial direction of the end groove The inner edge is inside the short-circuit ring, and an annular recess space is formed between the radially inner edge of the end groove and the inner surface of the short-circuit ring. .

  According to the present invention, a squirrel-cage induction motor that can withstand high-speed rotation with a simple structure can be provided.

It is a typical longitudinal section of a 1st embodiment of a cage type induction motor concerning the present invention. It is a typical longitudinal section of a 2nd embodiment of a cage type induction motor concerning the present invention. It is a typical longitudinal section of a 3rd embodiment of a cage type induction motor concerning the present invention.

  Hereinafter, embodiments of a squirrel-cage induction motor according to the present invention will be described with reference to the drawings. Here, parts that are common or similar to each other are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a schematic longitudinal sectional view of a first embodiment of a squirrel-cage induction motor according to the present invention. The squirrel-cage induction motor 100 according to the first embodiment includes a rotor 11 that can rotate around a rotation axis, a substantially cylindrical stator 12 that is disposed so as to surround the outer side of the rotor 11 in the radial direction, And a housing 13 that is disposed outside the child 12 and supports the stator 12.

  The stator 12 includes a cylindrical stator core 14 and a stator coil 15. The stator core 14 is obtained by laminating a large number of substantially annular steel plates extending in a plane perpendicular to the axis in the axial direction, and is arranged along the inner circumference thereof at intervals from each other in the circumferential direction. A plurality of stator grooves (not shown) are formed. The stator coil 15 is disposed in the stator groove of the stator core 14 and extends in the axial direction.

  The rotor 11 has a substantially cylindrical rotor core portion 21 extending along the rotation axis, and is disposed coaxially with the rotor core portion 21 on both axial sides of the rotor core portion 21 so as to be integrated with the rotor core portion 21. And a cylindrical rotor shaft portion 20 having a diameter smaller than that of the rotor core portion 21. A plurality of conductor bars 22 penetrate the vicinity of the outer periphery of the rotor core portion 21 in the axial direction and are spaced apart from each other in the circumferential direction. Moreover, the short circuit ring (end ring) 23 connects the axial direction edge parts of the conductor bar 22 in the circumferential direction, and is electrically short-circuited.

  The rotor shaft portion 20 extends through both end portions of the housing 13 and is rotatably supported by a bearing 24 supported by the housing 13.

  The rotor shaft portion 20 and the rotor core portion 21 are made of a magnetic material, and are made of, for example, steel. The conductor bar 22 and the short-circuit ring 23 need to be made of a material having high conductivity, and are made of, for example, copper, aluminum, or an alloy containing them as a main component.

  An annular end groove 30 centering on the rotation axis is formed at both axial ends of the rotor core portion 21, and the shaft of the rotor core portion 21 is formed radially outward of the end groove 30. An annular projecting portion 31 projecting in the axial direction is formed along the outer periphery of the direction end portion. The short-circuit ring 23 is embedded in the end groove 30, and the outer surface of the short-circuit ring 23 is in contact with the inner surface of the projecting portion 31.

  The conductor bar 22 and the short-circuit ring 23 are joined by welding or the like.

  In this embodiment, since the short-circuit ring 23 is embedded in the end groove 30 formed in the rotor core portion 21, the centrifugal force applied to the short-circuit ring 23 is supported on the inner surface of the overhang portion 31. . Thereby, the holding ring required by the prior art can be omitted, and a simple configuration can be obtained.

[Second Embodiment]
FIG. 2 is a schematic longitudinal sectional view of a second embodiment of the squirrel-cage induction motor according to the present invention. In the squirrel-cage induction motor 200 according to the second embodiment, the wide end groove 42 having a larger radial width than the end groove 30 of the first embodiment is formed at the axial end of the rotor core 21. Is formed. An annular projecting portion 31 projecting in the axial direction along the outer periphery of the axial end portion of the rotor core portion 21 is formed outside the wide end groove 42 in the radial direction. The short-circuit ring 23 is embedded along the inner periphery of the wide end groove 42, and the outer surface of the short-circuit ring 23 is in contact with the inner surface of the wide end groove 42. An annular recess space 43 is formed between the radially inner edge of the wide end groove 42 and the inner surface of the short-circuit ring 23.

  Other configurations are the same as those of the first embodiment.

  In this embodiment, as in the first embodiment, the centrifugal force applied to the short-circuit ring 23 is supported on the inner surface of the overhang portion 31. Thereby, the holding ring required by the prior art can be omitted, and a simple configuration can be obtained.

  Furthermore, in this embodiment, since the hollow space 43 is formed on the inner side in the radial direction of the short-circuit ring 23 and there is no rotor core portion 21 at that portion, the weight can be reduced as compared with the first embodiment.

[Third Embodiment]
FIG. 3 is a schematic longitudinal sectional view of a third embodiment of the cage induction motor according to the present invention. The squirrel-cage induction motor 300 according to the third embodiment is a modification of the first embodiment, and the rotor shaft portion 20 and the rotor core portion 52 are separately formed. The rotor shaft portion 20 has a single continuous cylindrical shape. A central hole extending in the axial direction is formed at the center of the rotor core portion 52, and the rotor shaft is formed in the center hole of the rotor core portion 52. The parts 20 are inserted and fixed to each other by shrink fitting or the like.

  In this embodiment, the rotor core 52 is formed by laminating a plurality of substantially annular steel plates extending in a plane perpendicular to the axis in the axial direction. Each steel plate is electrically insulated by an insulating coating.

  In this embodiment, the portion of the steel plate constituting the overhang portion 31 is separated from the portion of the steel plate on the radially inner side, and thus cannot be directly fixed to the rotor shaft portion 20. Therefore, what is necessary is just to integrate the part of the steel plate which comprises the overhang | projection part 31 with the other part of the rotor core part 52, for example by tightening in the axial direction with the volt | bolt (not shown) extended in an axial direction.

  Other configurations are the same as those of the first embodiment.

  According to this embodiment, as in the first embodiment, the short-circuit ring 23 is embedded in the end groove 30 formed in the rotor core 52, so that the centrifugal force applied to the short-circuit ring 23 is , And supported by the inner surface of the overhang portion 31. Thereby, the holding ring required by the prior art can be omitted, and a simple configuration can be obtained.

  Furthermore, according to this embodiment, since the rotor core part 52 which laminated | stacked the steel plate in the axial direction is used, the eddy current in an iron core is suppressed and the efficiency improvement as a cage type induction motor can be aimed at.

[Other Embodiments]
Although the said 3rd Embodiment was demonstrated as a deformation | transformation of 1st Embodiment, the wide end part groove | channel 42 similar to 2nd Embodiment is provided in the rotor core part 52 of the laminated structure of 3rd Embodiment. It is also possible.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 Rotor 12 Stator 13 Housing 14 Stator core 15 Stator coil 20 Rotor shaft part 21 Rotor core part 22 Conductor bar 23 Short-circuit ring 24 Bearing 30 End part groove 31 Overhang part 42 Wide end part groove 43 Indentation space 52 Rotor core 100, 200, 300 Cage induction motor

Claims (3)

A squirrel-cage induction motor comprising: a rotor rotatable around a rotation axis; and a stator disposed so as to surround a radially outer side of the rotor,
The rotor is
A rotor core portion whose main material is a magnetic material formed in a substantially cylindrical shape around the rotation axis;
A rotor shaft that is disposed coaxially with the axis of the rotor core portion on both sides in the axial direction of the rotor core portion, has a smaller diameter than the rotor core portion, and is integrally formed with the rotor core portion. And
A plurality of conductor bars arranged in the circumferential direction at intervals through the rotor iron core in the axial direction;
A short-circuit ring that connects the axial ends of the conductor bars in the circumferential direction to electrically short-circuit the axial ends of the conductor bars;
Have
An annular projecting portion projecting in the axial direction along the outer periphery of the axial end portion of the rotor core portion is formed,
The outer surface of the short ring is supported on the inner surface of the overhang,
An end groove extending in an annular shape around the rotation shaft and having a radial width larger than the radial width of the short-circuit ring is formed at an axial end portion of the rotor core portion, and the rotation shaft of the end groove is formed. The side far from the above constitutes the overhang,
The short-circuit ring is embedded and fixed in the end groove along the outer periphery of the end groove,
A radially inner edge of the end groove is inside the short-circuit ring, and an annular recess space is formed between the radially inner edge of the end groove and the inner surface of the short-circuit ring. Being
A squirrel-cage induction motor. The conductor bar and the short-circuit ring are made of copper, aluminum or an alloy based on them,
The squirrel-cage induction motor according to claim 1. A squirrel cage rotor supported rotatably in a stator,
A rotor core portion mainly composed of a magnetic material formed in a substantially cylindrical shape with the rotation axis as an axis;
A rotor shaft that is disposed coaxially with the axis of the rotor core portion on both sides in the axial direction of the rotor core portion, has a smaller diameter than the rotor core portion, and is integrally formed with the rotor core portion. And
A plurality of conductor bars arranged in the circumferential direction at intervals through the rotor iron core in the axial direction;
A short-circuit ring that connects the axial ends of the conductor bars in the circumferential direction to electrically short-circuit the axial ends of the conductor bars;
Have
An annular projecting portion projecting in the axial direction along the outer periphery of the axial end portion of the rotor core portion is formed,
The outer surface of the short ring is supported on the inner surface of the overhang,
An end groove extending in an annular shape around the rotation shaft and having a radial width larger than the radial width of the short-circuit ring is formed at an axial end portion of the rotor core portion, and the rotation shaft of the end groove is formed. The side far from the above constitutes the overhang,
The short-circuit ring is embedded and fixed in the end groove along the outer periphery of the end groove,
A radially inner edge of the end groove is inside the short-circuit ring, and an annular recess space is formed between the radially inner edge of the end groove and the inner surface of the short-circuit ring. Being
A squirrel-cage induction motor rotor.

Images