JP6745212B2 - Rotor and reluctance rotating electric machine - Google Patents

Description

Embodiments of the present invention relate to a rotor and a reluctance rotating electric machine.

The reluctance rotary electric machine includes a rotor and a stator. The rotor includes a shaft that is rotatably supported and extends in the axial direction about the rotation axis, and a rotor core that is externally fitted and fixed to the shaft. The stator is wound around the rotor core, the stator core having a plurality of teeth arranged at intervals on the outer periphery of the rotor core and having a plurality of teeth arranged at intervals in the circumferential direction. And a multi-phase multi-phase armature winding.

In the rotor core, a plurality of layers of hollow portions are formed per pole so as to be convex inward in the radial direction. By forming the hollow portion in this manner, a direction in which magnetic flux easily flows and a direction in which magnetic flux hardly flows are formed in the rotor core. Then, the reluctance rotating electric machine uses the reluctance torque generated by the hollow portion to rotate the shaft.

By the way, at the time of starting the reluctance rotary electric machine, it is necessary to detect the relative position between the stator core and the rotor core and supply power to a predetermined armature winding based on the relative position. Therefore, an inverter is required to start the reluctance rotating electric machine, which may increase the cost of the reluctance rotating electric machine.
Therefore, a so-called self-starting reluctance rotating electric machine that generates an induction torque has been proposed so that the reluctance rotating electric machine can be started without using an inverter.

In a self-starting reluctance rotating electric machine, a non-magnetic conductor is inserted in the cavity. The conductor protrudes from both axial ends of the rotor core, and both ends are joined to an annular short-circuit ring. With such a configuration, when three-phase alternating current is supplied to the armature winding of the stator, magnetic flux is formed on the predetermined teeth. At this time, an induced current is generated in the conductor bar of the rotor core in the asynchronous state until the stopped rotor rotates in synchronization with the rotational movement of the magnetic flux on the stator side. That is, the conductor bar functions as a secondary coil, and generates a starting torque for rotating the rotor with the stator.

Here, the positioning of the conductor with respect to the cavity is performed by short-circuit rings provided at both ends of this conductor. The conductor and the short-circuit ring are often joined by welding or the like in order to secure sufficient strength. As described above, the joining of the short-circuit ring and the conductor involves the work such as welding while positioning the conductor with respect to the cavity, and thus the work of assembling the rotor may be troublesome.

JP-A-8-182275 JP, 2003-274621, A

The problem to be solved by the present invention is to provide a rotor and a reluctance rotary electric machine that can improve the assembly work of the rotor.

The rotor of the embodiment has a shaft, a rotor core, an end plate made of a non-magnetic material, a conductor bar, and a short-circuit ring. The shaft rotates about the axis of rotation. The rotor core is fixed to the shaft, and a plurality of hollow portions are formed for each pole so as to be convex inward in the radial direction. The end plate is fixed to the shaft and holds the rotor core by pressing it from both sides in the rotation axis direction. The conductor bar is arranged in the cavity, extends along the rotation axis, and has both ends protruding through the end plates. The short-circuit rings are provided at both ends of the plurality of conductor bars and connect the plurality of conductor bars. Further, the end plate has an insertion hole through which the conductor bar can be inserted at a position corresponding to each conductor bar, and positions the conductor bar in the radial direction and the circumferential direction with respect to the rotor core.

The partial cross-section perspective view which shows the reluctance rotary electric machine of embodiment. Sectional drawing orthogonal to the axial direction which shows the rotor core of embodiment. The perspective view which shows the state which removed the end plate and short circuit ring of the rotor of embodiment. The perspective view which shows the state which attached the end plate to the rotor core of embodiment.

Hereinafter, a rotor and a reluctance electric rotating machine according to embodiments will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional perspective view showing a reluctance rotating electric machine (hereinafter, simply referred to as a rotating electric machine) 1.
As shown in the figure, a rotating electric machine 1 includes a housing 2, a stator 3 fixed in the housing 2, and a rotor 4 rotatably supported in the housing 2 around a rotation axis O. Equipped with. In the following description, a direction parallel to the rotation axis O is simply referred to as an axial direction, a direction around the rotation axis O is simply referred to as a circumferential direction, and a radial direction orthogonal to the rotation axis O is simply referred to as a radial direction. ..

The housing 2 includes a substantially cylindrical frame 5, and bearing brackets 6 and 7 that close the openings 5a and 5b at both axial ends of the frame 5. Each of the bearing brackets 6 and 7 is formed in a substantially disc shape. Bearings 8 and 9 for rotatably supporting the rotor 4 are provided at substantially the center of the bearing brackets 6 and 7 in the radial direction.

The stator 3 has a substantially cylindrical stator core 10 whose central axis is coaxial with the rotation axis O. The outer peripheral surface of the stator core 10 is fixed to the inner peripheral surface of the frame 5 by, for example, press fitting. The stator core 10 can be formed by laminating a plurality of electromagnetic steel plates or pressure-molding soft magnetic powder.
On the inner peripheral surface of the stator core 10, a plurality of teeth 11 projecting toward the rotation axis O and arranged at equal intervals in the circumferential direction are integrally formed. Although the specific shape of the tooth 11 is not particularly illustrated, the tooth 11 is formed in a substantially rectangular cross section. Then, slots (not shown) are formed between the adjacent teeth 11. The armature winding 13 is wound around each tooth 11 through these slots.

The rotor 4 is arranged radially inward of the stator core 10. The rotor 4 includes a shaft 14 that rotates around a rotation axis O, a substantially cylindrical rotor core 15 that is externally fitted and fixed to the shaft 14, and a plurality of conductor bars 41 that are provided in the rotor core 15. The rotor core 15 is provided with end plates (core retainers) 42 and short-circuit rings 45 arranged on both sides in the axial direction.

FIG. 2 is a cross-sectional view showing the rotor core 15 orthogonal to the axial direction.
As shown in FIG. 1 and FIG. 2, the rotor core 15 can be formed by laminating a plurality of electromagnetic steel plates or pressure-molding soft magnetic powder. The outer diameter of the rotor core 15 is set so that a predetermined air gap G is formed between the teeth 11 that face each other in the radial direction. Further, a through hole 16 penetrating in the axial direction is formed in the radial center of the rotor core 15. The shaft 14 is press-fitted or shrink-fitted into the through hole 16, so that the shaft 14 and the rotor core 15 rotate integrally.

Further, the rotor core 15 has four layers of cavity portions (flux barriers) 21, 22, 23, 24 (first cavity portion 21, second cavity portion 22, The third cavity portion 23 and the fourth cavity portion 24) are formed side by side in the radial direction. That is, the first hollow portion 21 is formed at a position closest to the shaft 14 (the radially innermost side of the rotor core 15), and the second hollow portion 22 is sequentially arranged in the direction away from the shaft 14 (radially outer side). The third cavity portion 23 and the fourth cavity portion 24 are formed side by side. Then, the fourth hollow portion 24 is arranged at a position farthest from the shaft 14 (outermost in the radial direction).

The cavities 21 to 24 are formed along the flow of magnetic flux formed when the armature winding 13 is energized. That is, each of the cavities 21 to 24 is formed in a curved shape so that the center in the circumferential direction is located on the innermost side in the radial direction (convex shape toward the inner side in the radial direction). As a result, in the rotor core 15, a direction in which magnetic flux easily flows and a direction in which magnetic flux hardly flows are formed. In the following description, the longitudinal direction of each cavity 21, 22, 23, 24 when viewed from the axial direction may be simply referred to as the longitudinal direction of the cavity 21, 22, 23, 24.

Here, in this embodiment, the direction in which the magnetic flux easily flows is referred to as the q-axis. Further, the direction along the radial direction that is electrically and magnetically orthogonal to the q axis is referred to as the d axis. That is, each of the cavities 21 to 24 has a multilayer structure in the radial direction along the d axis.
More specifically, in the q-axis direction of the rotor core 15, the direction in which the flow of the magnetic flux is not obstructed by the cavity portions 21 to 24 is referred to as the q-axis. That is, a positive magnetic potential (for example, the N pole of the magnet is brought closer) to an arbitrary circumferential angular position of the outer peripheral surface 15a of the rotor core 15, and one pole (90 degrees in mechanical angle in the case of the present embodiment) ) A rotation axis line when the most magnetic flux flows when a negative magnetic potential (for example, the S pole of a magnet is brought closer) is given to another shifted peripheral angular position and the arbitrary position is shifted in the circumferential direction. The direction from O to any position is defined as the q-axis. And the longitudinal direction of each cavity 21-24 is a q-axis.

On the other hand, the direction in which the flow of magnetic flux is blocked by each of the cavities 21 to 24, that is, the direction magnetically orthogonal to the q axis is referred to as the d axis. In the present embodiment, the direction parallel to the direction in which the two rotor core portions separated into the region close to the rotation axis O and the region distant from the rotation axis O by the cavities 21 to 24 are the d-axis. Further, when each of the hollow portions 21 to 24 is formed in multiple layers as in this embodiment (four layers in this embodiment), the layer overlapping direction is the d axis. In the present embodiment, the d-axis is not limited to being electrically and magnetically orthogonal to the q-axis, and may intersect with a certain angular width (for example, about 10 degrees in mechanical angle) from the orthogonal angle.

As described above, the rotor core 15 is configured with four poles, and four layers of cavity portions 21 to 24 are formed per pole (a circumferential angle region of 1/4 circumference of the rotor core 15). It will be. And 1 pole means the area|region between q axes. That is, each of the cavities 21 to 24 is formed so as to be curved inward in the radial direction so that the d-axis is located on the innermost side in the radial direction.

Further, each of the cavities 21 to 24 is curved and formed so that both ends in the longitudinal direction are located on the outer peripheral portion of the rotor core 15 when viewed in the axial direction. Each of the cavities 21 to 24 is formed so as to be along the q axis at a position closer to both ends in the longitudinal direction and orthogonal to the d axis at a position closer to the center in the longitudinal direction.
Further, in the q-axis direction, bridges 26, 27, 28, 29 (first bridge 26, second bridge) are respectively provided between both longitudinal ends of each of the hollow portions 21-24 and the outer peripheral surface 15a of the rotor core 15. 27, a third bridge 28, and a fourth bridge 29) are formed.

Further, of the respective hollow portions 21 to 24, center bridges 61, 62, 63 (first center bridge 61, 61, 62, 63) are provided at the longitudinal center of the first hollow portion 21, the second hollow portion 22, and the third hollow portion 23, respectively. A second center bridge 62 and a third center bridge 63) are formed. The center bridges 61, 62, 63 are provided so as to straddle the hollow portions 21, 22, 23 along the d-axis direction. These center bridges 61, 62, 63 are for making the rotor core 15 in which the hollow portions 21-24 are formed difficult to deform.

FIG. 3 is a perspective view showing a state in which the end plate 42 and the short circuit ring 45 of the rotor 4 are removed.
As shown in FIGS. 2 and 3, the plurality of conductor bars 41 provided in the rotor core 15 are inserted into the hollow portions 21 to 24. Specifically, the conductor bars 41 are inserted at both longitudinal ends of the first cavity portion 21, the second cavity portion 22, and the third cavity portion 23, respectively. Further, the conductor bar 41 is inserted in the longitudinal center of the fourth hollow portion 24.

Each conductor bar 41 is a plate-shaped member that has a substantially rectangular cross-section orthogonal to the axial direction and is elongated and uniform in the axial direction. The conductor bar 41 projects from both axial ends of the rotor core 15. The conductor bar 41 is made of a non-magnetic and conductive material such as an aluminum alloy or a copper alloy. Further, the conductor bar 41 inserted in the first cavity portion 21, the second cavity portion 22, and the third cavity portion 23 is provided with a predetermined amount from the corresponding first bridge 26, second bridge 27, and third bridge 28. It is arranged with a gap.

FIG. 4 is a perspective view showing a state in which the end plate 42 is attached to the rotor core 15.
As shown in the figure, the end plates 42 are arranged at both axial ends of the rotor core 15 so as to overlap the rotor core 15. The end plate 42 is formed of a non-magnetic material (for example, hard resin) into a substantially disk shape, and its outer diameter is set to be substantially the same as the outer diameter of the rotor core 15. The end plate 42 presses the rotor core 15 from both sides in the axial direction, restricts the axial movement of the rotor core 15 with respect to the shaft 14, and forms the rotor core 15 by laminating a plurality of electromagnetic steel plates. They are integrated. Further, the end plates 42 close the openings at both axial ends of the hollow portions 21 to 24 formed in the rotor core 15.

A through hole 42a into which the shaft 14 can be press-fitted or shrink-fitted is formed in the center of the end plate 42 in the radial direction. As a result, the end plate 42 is fixed to the shaft 14 and movement of the rotor core 15 with respect to the shaft 14 in the axial direction is restricted.
The shaft 14 is inserted into the through hole 42a of the end plate 42, and a key is provided on either the inner peripheral surface of the through hole 42a or the outer peripheral surface of the shaft 14, and a key groove capable of receiving the key is provided on the other side. Therefore, the end plate 42 may be fixed to the shaft 14.

Further, conductor insertion holes 42b are formed in the end plates 42 at positions corresponding to the conductor bars 41 inserted in the rotor core 15. The conductor bar 41 is inserted through these conductor insertion holes 42b. Then, the conductor bar 41 projects to the outer surface 42c of the end plate 42 opposite to the rotor core 15 via the conductor insertion hole 42b.
Here, the conductor bar 41 may be press-fitted into the conductor insertion hole 42b of the end plate 42. In the case of press-fitting, both end sides in the axial direction of the conductor bar 41 may be formed so as to be slightly tapered toward the ends. With this configuration, even when the conductor bar 41 is press-fitted into the conductor insertion hole 42b, the conductor bar 41 can be smoothly inserted into the conductor insertion hole 42b.

As shown in FIG. 1, both ends in the axial direction of the conductor bar 41 projecting through the conductor insertion hole 42 b of the end plate 42 are short-circuited by the short-circuit ring 45.
The short-circuit ring 45 is an annular member that is arranged apart from the end plate 42 in the axial direction by a predetermined distance K1. The radial center of the short circuit ring 45 also coincides with the rotation axis O. Like the conductor bar 41, the short circuit ring 45 is made of a non-magnetic and conductive material. Specifically, the material of the short-circuit ring 45 is preferably the same material as the conductor bar 41, and is preferably formed of, for example, an aluminum alloy or a copper alloy. However, it is not limited to this.

Conductor insertion holes 45a are formed in the short-circuit ring 45 at positions corresponding to the conductor bars 41, respectively. The conductor bar 41 is inserted through the conductor insertion holes 45a. The short-circuit ring 45, through which the conductor bar 41 is inserted, is joined to the conductor bar 41 by brazing, for example.

Here, for example, when the short-circuit ring 45 and the conductor bar 41 are joined by brazing, the predetermined distance K1 between the end plate 42 and the short-circuit ring 45 is determined by the conductor insertion hole 45a of the short-circuit ring 45 and the end of the conductor bar 41. It is set so that the brazing material sufficiently wraps around the part.
The joining of the short-circuit ring 45 and the conductor bar 41 is not limited to brazing, and it is sufficient that the short-circuit ring 45 and the conductor bar 41 can be joined. For example, the conductor bar 41 can be pressed into the conductor insertion hole 45a, or welding other than brazing can be adopted.

Next, a method of assembling the rotor 4 will be described.
First, the rotor core 15 and the end plate 42 are assembled to the shaft 14 by press fitting, shrink fitting, or the like, and the conductor bars 41 are respectively installed in the hollow portions 21 to 24 of the rotor core 15 and the conductor insertion holes 42b of the end plate 42. insert. At this time, the inner surface of the end plate 42 is brought into contact with both axial ends of the rotor core 15. Further, the positioning of the rotor core 15 and the end plate 42 in the circumferential direction is performed by using a jig or the like (not shown).

Here, conductor insertion holes 42b are formed in the end plate 42 at positions corresponding to the conductor bars 41 inserted in the rotor core 15. The conductor bar 41 is inserted through these conductor insertion holes 42b. That is, the radial and circumferential movements of the conductor bar 41 are restricted by being inserted into the conductor insertion holes 42b. Therefore, since the end plate 42 is fixed to the shaft 14, the conductor bar 41 is accurately positioned in the radial direction and the circumferential direction with respect to the rotor core 15. When the conductor bar 41 is press-fitted into the conductor insertion hole 42b of the end plate 42, the conductor bar 41 is also axially positioned with respect to the end plate 42.

Next, the conductor insertion holes 45a of the short-circuit ring 45 are inserted into both ends of each conductor bar 41 in the axial direction. Then, the axial ends of each conductor bar 41 and the short-circuit ring 45 are joined by brazing or the like. At this time, since the conductor bar 41 is positioned with respect to the rotor core 15 in at least the radial direction and the circumferential direction by the end plate 42, the rotor core 15 is bonded to the rotor core 15 when the short-circuit ring 45 and the conductor bar 41 are joined. It is not necessary to consider the positioning of the conductor bar 41. Therefore, the work of joining the short-circuit ring 45 and the conductor bar 41 can be easily performed. Then, by assembling the short-circuit ring 45 and the conductor bar 41, the assembly work of the rotor 4 is completed.

Next, the operation of the rotary electric machine 1 will be described.
When driving the rotary electric machine 1, three-phase alternating current is supplied to the armature winding 13 of the stator 3. Then, magnetic flux is formed on the predetermined teeth 11. Then, the teeth 11 on which the magnetic flux is formed are sequentially switched along the rotation direction (circumferential direction) of the rotor 4 (the formed magnetic flux rotates and moves).
At this time, an induced current is generated in the conductor bar 41 provided in the rotor core 15 in an asynchronous state until the stopped rotor 4 rotates in synchronization with the rotational movement of the magnetic flux on the stator 3 side. That is, each conductor bar 41 functions as a secondary coil, and generates a starting torque for rotating the rotor 4 with the stator 3.

Here, the conductor bars 41 arranged at both longitudinal ends of the first cavity portion 21, the second cavity portion 22, and the third cavity portion 23 respectively correspond to the corresponding first bridge 26, second bridge 27, and second bridge 27. The three bridges 28 are arranged with a predetermined gap. Since the conductor bar 41 is accurately positioned by the end plate 42, the predetermined gaps between the first bridge 26, the second bridge 27, and the third bridge 28 and the conductor bar 41 are also accurately determined.

It is difficult for magnetic flux to pass through the gap. Therefore, by forming the predetermined gap, the magnetic flux formed in the stator 3 may be linked to the conductor bar 41, and a harmonic current that does not contribute to the rotation of the rotor 4 may flow in the conductor bar 41. Suppressed. In other words, the harmonic magnetic flux resulting from the torque ripple generated in the air gap G between the stator 3 and the rotor 4 is less likely to interlink with each conductor bar 41, and the harmonic secondary copper loss is less likely to occur.

As described above, in the above-described embodiment, the conductor insertion hole 42b is formed in the end plate 42, and the conductor bar 41 is inserted into the conductor insertion hole 42b, so that the conductor bar for the rotor core 15 is inserted through the end plate 42. Positioning of 41 in the radial and circumferential directions is performed. That is, the positioning of the conductor bar 41 with respect to the rotor core 15 is performed by the end plate 42. On the other hand, in order to short-circuit the conductor bars 41 with each other, the conductor bars 41 and the short-circuit ring 45 are joined together by this joining work alone. In this way, the positioning work of the conductor bar 41 with respect to the rotor core 15 and the joining work of the short-circuit ring 45 and the conductor bar 41 can be distinguished, and it is not necessary to perform them at the same time. Therefore, the assembly work of the rotor 4 can be improved.

Further, by fixing the conductor bar 41 to the conductor insertion hole 42b of the end plate 42 by press fitting or the like, the conductor bar 41 can be axially positioned with respect to the end plate 42. In other words, the end plate 42 also enables the conductor bar 41 to be positioned with respect to the rotor core 15. Therefore, the work of joining each conductor bar 41 and the short circuit ring 45 can be further facilitated.

In addition, in the above-described embodiment, the case where the short-circuit ring 45 is arranged apart from the end plate 42 in the axial direction by the predetermined distance K1 has been described. However, the configuration is not limited to this, and the short circuit ring 45 and the end plate 42 may be brought into contact with each other without providing the predetermined interval K1 between the short circuit ring 45 and the end plate 42. With this configuration, when the conductor bar 41 is joined to the short circuit ring 45, the movement of the short circuit ring 45 in the axial direction is restricted. Therefore, it is possible to easily position the conductor bar 41 in the axial direction with respect to the rotor core 15.

Further, in the above-described embodiment, the case where the conductor bar 41 is provided in each of the cavities 21 to 24 and the starting torque for rotating the rotor 4 is generated is described. However, the present invention is not limited to this, and the conductor bar 41 may be provided only in any of the hollow portions 21 to 24 among the hollow portions 21 to 24. Even with such a configuration, when the rotating electric machine 1 is driven, the starting torque can be generated in the rotor 4.
Further, in the above-described embodiment, the case where the rotor core 15 is formed with four layers of cavity portions 21 to 24 in each of the circumferential angle regions of 1/4 circumference (per pole) has been described. .. However, the present invention is not limited to this, and a cavity having a plurality of layers of four layers or more may be formed.

Further, in the above-described embodiment, each of the cavities 21 to 24 is curved so that the center in the circumferential direction is located on the innermost side in the radial direction (so as to have a convex shape toward the inner side in the radial direction). The case was explained. However, the present invention is not limited to this, and each of the hollow portions 21 to 24 may be formed so as to be convex inward in the radial direction. That is, the hollow portions 21 to 24 do not have to be curved.
Further, in the above-described embodiment, the case where the rotor core 15 is configured with four poles has been described. However, the present invention is not limited to this, and the rotor core 15 may have four or more poles.

According to at least one embodiment described above, the conductor insertion hole 42b is formed in the end plate 42, and the conductor bar 41 is inserted into the conductor insertion hole 42b, so that the rotor core 15 is inserted through the end plate 42. The conductor bar 41 is positioned in the radial direction and the circumferential direction. That is, the positioning of the conductor bar 41 with respect to the rotor core 15 is performed by the end plate 42. On the other hand, in order to short-circuit the conductor bars 41 with each other, the conductor bars 41 and the short-circuit ring 45 are joined together by this joining work alone. In this way, the positioning work of the conductor bar 41 with respect to the rotor core 15 and the joining work of the short-circuit ring 45 and the conductor bar 41 can be distinguished, and it is not necessary to perform them at the same time. Therefore, the assembly work of the rotor 4 can be improved.

Further, by fixing the conductor bar 41 to the conductor insertion hole 42b of the end plate 42 by press fitting or the like, the conductor bar 41 can be axially positioned with respect to the end plate 42. In other words, the end plate 42 also enables the conductor bar 41 to be positioned with respect to the rotor core 15. Therefore, the work of joining each conductor bar 41 and the short circuit ring 45 can be further facilitated.

While some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the 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. The embodiments and their modifications are included in the scope of the invention and the scope thereof, as well as in the invention described in the claims and the scope of equivalents thereof.

DESCRIPTION OF SYMBOLS 1... Reluctance rotary electric machine, 14... Shaft, 15... Rotor iron core, 21... 1st cavity part (cavity part), 22... 2nd cavity part (cavity part), 23... 3rd cavity part (cavity part), 24 ... fourth cavity (cavity), 41... conductor bar, 42... end plate, 42b... conductor insertion hole (insertion hole), 45... short-circuit ring, O... rotation axis

Claims (4)

A shaft that rotates around the axis of rotation,
A rotor core that is fixed to the shaft and has a plurality of layers of hollow portions that are convex toward the inner side in the radial direction for each pole;
An end plate made of a non-magnetic material that is fixed to the shaft and holds the rotor core by pressing it from both sides in the rotation axis direction,
A plurality of conductor bars disposed in the cavity, extending along the rotation axis, and having both ends protruding through the end plate;
A short-circuit ring provided at both ends of the plurality of conductor bars and connecting the plurality of conductor bars,
The said end plate has the insertion hole which can insert said conductor bar in the position corresponding to each said conductor bar, The rotor which positions the said conductor bar with respect to the said rotor core in the radial direction and the circumferential direction. The rotor according to claim 1, wherein the conductor bar is fixed to the end plate. The rotor according to claim 1 or 2, wherein the conductor bar is press-fitted into the insertion hole of the end plate. A rotor according to any one of claims 1 to 3,
A stator that is provided so as to surround the periphery of the rotor, around which an armature winding is wound,
Reluctance rotating electric machine equipped with.

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