JP7382293B2 - Blocky rotor, rotating electric machine, and rotor slot forming method - Google Patents

Description

The present invention relates to a block rotor, a rotating electrical machine using the same, and a rotor slot forming method.

In an induction rotating electric machine or a synchronous rotating electric machine using a block rotor, a plurality of rotor slots are formed near the radial surface of the iron core portion, spaced apart from each other in the circumferential direction, and penetrating in the axial direction. be done. A secondary conductor, such as a conductor bar or rotor winding, passes through each rotor slot.

In high-speed machines used at high rotational speeds, in order to ensure greater mechanical strength, instead of using a laminated structure of electromagnetic steel sheets for the rotor core, the rotor core is integrated with the rotor shaft and a block magnetic pole is used. A type rotor (block rotor) may be used. In such a case, since the centrifugal force acting on the secondary conductor increases, it is necessary to ensure that the secondary conductor does not fall off radially outward. Since the direction of centrifugal force coincides with the direction in which the slots are formed, methods such as pressing a secondary conductor onto the rotor core have been adopted (see Patent Document 1).

US Patent No. 6,933,647

In the case of a laminated type of electromagnetic steel plates, the electromagnetic steel plates are electrically insulated from each other by an insulating material, and the generation of leakage current in the axial direction is prevented. On the other hand, in the case of a block rotor, since the iron core portion is electrically integrated, leakage current occurs in the axial direction, which causes a decrease in efficiency.

Further, since the block rotor is mainly used in high-speed machines, the centrifugal force applied to the secondary conductor in the rotor slot is large, so it is important to ensure structural integrity against centrifugal force.

Furthermore, in the case of laminated type magnetic steel sheets, the rotor slots can be formed by punching the magnetic steel sheets into a shape such that the rotor slots are formed in the laminated state, while in the case of a block rotor, It is necessary to form grooves on the surface of the core portion to form rotor slots that are spaced apart from each other in the circumferential direction and extend through the rotor in the axial direction.

Therefore, an object of the present invention is to suppress a decrease in efficiency and ensure structural soundness of a block rotor.

In order to achieve the above-mentioned object, a block rotor according to the present invention includes a shaft portion that extends in the axial direction and is rotatably supported around a rotation axis , and a shaft portion that is integrally formed with the shaft portion and that extends from the shaft portion. a cylindrical rotor core portion having a large diameter and formed with a plurality of rotor slots arranged circumferentially at intervals and extending in the axial direction; and a plurality of rotor slots penetrating through the rotor slots. an electrical conductor, each of the plurality of rotor slots having a first inclination angle at a first inclination angle with respect to a virtual plane that includes the rotation axis and extends in a radial direction. a side surface, a first bottom surface, a first connecting surface connecting the first side surface and the first bottom surface, and a second side surface inclined at a second inclination angle with respect to the virtual plane. , a second bottom surface, and a second connection surface connecting the second side surface and the second bottom surface, and the second inclination angle is smaller than the first inclination angle. , characterized in that the width at the bottom of the rotor core is larger than the width at the outer surface of the rotor core .

Further, the rotating electric machine according to the present invention includes the aforementioned block rotor, a cylindrical stator core provided on the radially outer side of the rotor core, and a cylindrical stator core provided on the radially inner surface of the stator core. a stator winding that passes through a plurality of stator slots formed at intervals in the axial direction and extending in the axial direction; and the shaft extending in the axial direction with the rotor core portion sandwiched therebetween. and two bearings supporting the block rotor on each side of the rotor.

Further, the rotor slot forming method according to the present invention includes: a shaft portion that extends in the axial direction and is rotatably supported around a rotating shaft; and a shaft portion that is integrally formed with the shaft portion and has a larger diameter than the shaft portion. a cylindrical rotor core portion in which a plurality of rotor slots extending in the axial direction are formed and are spaced apart from each other in the circumferential direction; a plurality of electrical conductors coupled to each other on both outer sides in the axial direction, and forming a plurality of rotor slots spaced apart from each other in the circumferential direction and extending in the axial direction; A rotor slot forming method, comprising: a first side surface that is inclined at a first inclination angle with respect to a virtual plane that includes the rotation axis and extends in a radial direction; a first bottom surface; the first side surface and the a first groove machining step of machining a first groove having a first connection surface that connects the first bottom surface ; a second side surface that is inclined at a second inclination angle with respect to the virtual plane; a second groove machining step for machining a first groove having a second bottom surface and a second connection surface connecting the second side surface and the second bottom surface ; Each of the rotor slots is characterized in that the second angle of inclination is smaller than the first angle of inclination, and the width at the bottom is larger than the width at the outer surface of the rotor core.

According to the present invention, it is possible to suppress a decrease in efficiency and ensure structural soundness of a block rotor.

FIG. 1 is a longitudinal cross-sectional view showing the configuration of a rotating electrical machine according to an embodiment. FIG. 2 is a partial cross-sectional view showing the configuration of a block rotor and stator according to an embodiment. FIG. 2 is a flow diagram showing the procedure of a rotor slot forming method according to an embodiment. FIG. 3 is a cross-sectional view showing a state during first groove machining in the rotor slot forming method according to the embodiment. FIG. 6 is a cross-sectional view showing a state during second groove machining in the rotor slot forming method according to the embodiment. It is a flowchart which shows the procedure of the modification of the rotor slot formation method based on embodiment. FIG. 3 is a partial cross-sectional view showing rotor slots of the block rotor according to the embodiment. FIG. 7 is a cross-sectional view showing a state during groove machining according to a comparative example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A block rotor, a rotating electrical machine using the same, and a rotor slot forming method according to the present invention will be described below with reference to the drawings. Here, parts that are the same or similar to each other are given the same reference numerals, and redundant explanation will be omitted.

FIG. 1 is a longitudinal cross-sectional view showing the configuration of a rotating electrical machine according to an embodiment.
The rotating electrical machine 100 includes a block rotor 10, a stator 20, a bearing 31, and a frame 40. In the following, a squirrel-cage induction rotating electrical machine is used as an example of the rotating electrical machine 100, but the present invention is similarly applicable to a wound type induction rotating electrical machine and a synchronous rotating electrical machine.

The block rotor 10 is a block magnetic pole type rotor in which the rotor core is integrated with the rotor shaft for the purpose of ensuring greater mechanical strength. It has a plurality of secondary conductors 15 as conductors and two short circuit rings 16. Note that, in the following, the secondary conductor 15 is a conductor bar of a squirrel-cage rotating electrical machine, but in the case of a wound type induction rotating electrical machine and a synchronous rotating electrical machine, the secondary conductor 15 is a rotor winding. Just read it differently.

The integral rotor 11 is a rotationally symmetrical integral body, and has a shape that is a combination of cylindrical shapes having different diameters in the direction of the rotation axis (hereinafter referred to as the axial direction). The vicinity of the center in the axial direction has a cylindrical shape with a large diameter and forms a rotor core portion 13 . On both sides of the rotor core portion 13 in the axial direction, narrow diameter portions 12 having a smaller diameter than the rotor core portion 13 are formed. The narrow diameter portions 12 on both sides in the axial direction are rotatably supported by bearings 31, respectively.

As will be described later, a plurality of secondary conductors 15 extend in the axial direction and pass through the vicinity of the radial surface of the rotor core portion 13 . Each of the secondary conductors 15 projects to both axially outer sides of the rotor core portion 13 by the same length. On each of the outer sides in the axial direction, the ends of the plurality of secondary conductors 15 are electrically and mechanically coupled to the annular short-circuit ring 16, thereby electrically coupled to each other. The secondary conductor 15 and the short-circuit ring 16 are made of a material having higher conductivity than that of the rotor core 13. For example, the rotor core 13 is made of steel or low alloy steel, while the secondary conductor 15 and shorting ring 16 are made of copper, aluminum, or the like.

Stator 20 has a stator core 21 and a plurality of stator windings 22 . The stator core 21 is provided on the radially outer side of the rotor core portion 13 of the block rotor 10 with an annular gap 19 interposed therebetween. Stator core 21 has a cylindrical shape, and stator winding 22 passes through the vicinity of the inner surface of stator core 21 .

The frame 40 accommodates the stator 20 and the rotor core 13. Bearing brackets 32 are provided at both ends of the frame 40 in the axial direction. The bearing brackets 32 each statically support the bearings 31.

FIG. 2 is a partial cross-sectional view showing the configuration of the block rotor and stator according to the embodiment.
A plurality of rotor slots 70 are formed in a radially outer portion of the narrow diameter portion 12 of the rotor core portion 13 of the integral rotor 11 of the block rotor 10 and are open to the radially outer surface. The rotor slots 70 are circumferentially spaced from one another and extend axially through the rotor slots.

Each rotor slot 70 is tilted in the circumferential direction with respect to a plane S that includes the rotation axis X of the block rotor 10 and passes through the center of the opening when its radially outer opening is vertically upward. ing. Further, the rotor teeth 13a are formed by the rotor slots 70 adjacent to each other in the circumferential direction, and the rotor teeth 13a are also inclined in the circumferential direction.

Each rotor slot 70 accommodates a secondary conductor 15 as a rotor conductor.

Stator slots 21a are formed in the stator core 21 of the stator 20, spaced apart from each other in the circumferential direction, and passing through the stator slots 21a in the axial direction. A conductor of the stator winding 22 is accommodated in each stator slot 21a. The inner surfaces on both sides of the stator slot 21a are formed parallel to the plane S described above.

FIG. 3 is a flow diagram showing the procedure of the rotor slot forming method according to the embodiment.
First, the groove machining device is set (step S01). The groove machining device includes a mounting device (not shown) that is equipped with an integrated rotor 11 and rotates by a specified angle in the circumferential direction, and a tool that forms the rotor slot 70 and moves in the axial direction while rotating. There is a rotary drive unit 85 (FIGS. 4 and 5) that performs the rotation.

Next, first groove machining is performed (step S02).
FIG. 4 is a cross-sectional view showing a state during first groove processing in the rotor slot forming method according to the embodiment.

The first groove cutting tool 81 is held by a rotational drive section 85 . The first groove cutting tool 81 has a side portion 81a, a bottom portion 81b, and a connecting portion 81c that connects these portions. The radius of curvature of the cross section of the connecting portion 81c is R1a.

The shaded part is a cutting part having the cutting edge of the first groove cutting tool 81. Further, the rotation drive unit 85 grips the first groove cutting tool 81 and rotates the first groove cutting tool 81 around its axis. The first groove cutting tool 81 has a cutting edge formed on each of the side portion 81a of the diagonally shaded portion, the bottom portion 81b, and the connecting portion 81c.

The first groove part 71 of the rotor slot 70 is rotated, for example, by arranging the first groove bit 81 on the axially outer side of the rotor core part 13 in a direction inclined by a first inclination angle Θ1 with respect to the plane S. It is set in the rotation drive unit 85 so that it is at a position corresponding to the depth of the child slot 70. In this state, the first groove cutting tool 81 is rotated. Next, the rotary drive unit 85 that supports the first groove cutting tool 81 is moved in the axial direction (towards the back of FIG. 4).
As a result, a first groove portion 71 penetrating in the depth direction in FIG. 4 is formed.

Next, it is determined whether all first grooves 71 have been machined in the circumferential direction (step S03). If it is not determined that all the tests have been carried out (step S03 NO), the angle of the integrated rotor 11 is changed (step S04). Specifically, the integrated rotor 11 is rotated to the next circumferential angular position by the mounting device. Thereafter, steps S02 and subsequent steps are repeated.

If it is determined that all machining has been performed (step S03 YES), the machining state of the first groove portion 71 is confirmed (step S05). Specifically, for example, it is checked whether there is any abnormality in the condition of the processed surface. The same applies to step S09, which will be described later.

Next, a second groove machining is performed (step S06).
FIG. 5 is a cross-sectional view showing a state during second groove processing in the rotor slot forming method according to the embodiment.

The second groove cutting tool 82 is held by a rotation drive section 85 . The second groove cutting tool 82 has a side portion 82a, a bottom portion 82b, and a connecting portion 82c that connects these portions. The radius of curvature of the cross section of the connecting portion 82c is R2a. Note that the radius of curvature R1a of the connecting portion 81c of the first groove cutting tool 81 described above is larger than the radius of curvature R2a.

The shaded part is a cutting part having the cutting edge of the second groove cutting tool 82. Further, the rotation drive unit 85 grips the second groove cutting tool 82 and rotates the second groove cutting tool 82 around its axis. The second groove cutting tool 82 has a cutting edge formed on each of the side portion 82a of the diagonally shaded portion, the bottom portion 82b, and the connecting portion 82c.

The second groove part 72 of the rotor slot 70 is rotated, for example, by arranging the second groove bit 82 on the axially outer side of the rotor core part 13 in a direction inclined by a second inclination angle Θ2 with respect to the plane S. It is set in the rotation drive unit 85 so that it is at a position corresponding to the depth of the child slot 70. Here, the second inclination angle Θ2 is smaller than the first inclination angle Θ1 of the first groove cutting tool 81.

In this state, the second groove cutting tool 82 is rotated. Next, the rotation drive unit 85 that supports the second groove cutting tool 82 is moved in the axial direction (toward the back of FIG. 5).
As a result, a second groove portion 72 penetrating in the depth direction in FIG. 5 is formed.

Next, it is determined whether all the second grooves 72 have been machined in the circumferential direction (step S07). If it is not determined that all the tests have been carried out (step S07 NO), the angle of the integrated rotor 11 is changed (step S08). Specifically, the integrated rotor 11 is rotated to the next circumferential angular position by the mounting device. Then, steps S06 and subsequent steps are repeated.

If it is determined that all machining has been performed (step S07 YES), the machining state of the second groove portion 72 is confirmed (step S09).

Next, finishing and inspection are performed (step S10).
The second groove part 72 is formed by the second groove cutting tool 82 in a state where the first groove part 71 has already been formed. In this case, for the second groove cutting tool 82, the space of the first groove portion 71 that has already been formed is placed on one side, and the target portion where the space is not formed is cut, that is, the cutting is performed in a state of uneven contact. Therefore, the conditions are stricter than when forming the first groove portion 71.

For this reason, the second inclination angle Θ2 is made small. As a result, the cutting depth becomes shallower than when the first groove portion 71 was formed, and cutting resistance decreases.

Further, the radius of curvature of the connecting portion 82c of the second groove cutting tool 82 is made smaller than the radius of curvature of the connecting portion 82c of the second groove cutting tool 82. This point also has the effect of reducing cutting resistance.

FIG. 6 is a flowchart showing a procedure of a modified example of the rotor slot forming method according to the embodiment. In the case shown in the flowchart of FIG. 3, the procedure is to form the first groove portion 71 over the entire circumference, and then form the second groove portion 72 over the entire circumference.

On the other hand, in a modification shown in the flowchart of FIG. 6, the first groove 71 and the subsequent second groove 72 are formed at each angular position of the integrated rotor 11.

That is, after setting the groove machining device (step S21), performing the first groove machining (step S22), confirming the machining state (step S23), implementing the second groove machining (step S24), and confirming the machining state (step S24). After step S25), it is determined whether or not all the steps have been carried out in the circumferential direction (step S26), and if not all the steps have been carried out (step S26 NO), the angle of the integrated rotor 11 is changed (step S27). Then, steps S22 and subsequent steps are repeated.

In such a modified example, compared to the procedure shown in FIG. 3, it is necessary to switch between the first groove bit 81 and the second groove bit 82 each time, but the number of times the angle of the integrated rotor 11 is changed is halved. That's enough. Rather than setting the first groove cutting tool 81 and the second groove cutting tool 82 alternately in one drive device, both the first groove cutting tool 81 and the second groove cutting tool 82 are each equipped with an integrated rotor. This is an effective method if the settings are such that access to 11 is possible.

FIG. 7 is a partial cross-sectional view showing rotor slots of the block rotor according to the embodiment.
Each of the rotor slots 70 has a first groove portion 71 and a second groove portion 72 portion. The first groove portion 71 has a first groove side surface 71a, a first groove bottom surface 71b, and a first groove connection surface 71c, and the second groove portion 72 has a second groove side surface 72a, a second groove bottom surface 72b, and a first groove connecting surface 71c. It has a second groove connection surface 72c.

The first groove portion 71 and the second groove portion 72 are adjacent to each other at the boundary between the first groove bottom surface 71b and the second groove bottom surface 72b. On the other hand, the first groove side surface 71a of the first groove section 71 and the second groove side surface 72a of the second groove section 72 are opposed to each other. The first inclination angle Θ1, which is the inclination angle of the first groove side surface 71a of the first groove part 71 with respect to the radial direction, is the second inclination angle Θ1, which is the inclination angle of the second groove part side surface 72a of the second groove part 72 with respect to the radial direction. Since it is larger than the angle Θ2, the width D2 at the bottom is larger than the width D1 at the outer surface of the rotor core 13 in the direction perpendicular to the center plane of the rotor slot 70. Therefore, it is possible to prevent the secondary conductor 15 from protruding outward in the radial direction.

Further, due to centrifugal force applied to the secondary conductor 15 while the block rotor 10 is rotating, a load is applied radially outward from the secondary conductor 15 to the rotor teeth 13a. Due to the circumferential component of this load, a bending load in the circumferential direction indicated by the broken arrow M is applied to the rotor teeth 13a.

Due to the bending load on the rotor teeth 13a, tensile stress is applied particularly to the first groove connecting surface 71c between the first groove side surface 71a and the first groove bottom surface 71b. On the other hand, compressive stress is applied to the second groove connecting surface 72c between the second groove side surface 72a and the second groove bottom surface 72b.

The first groove connection surface 71c has a radius of curvature larger than the radius of curvature of the second groove connection surface 72c, and can alleviate stress concentration.

FIG. 8 is a cross-sectional view showing a state during groove machining according to a comparative example. The comparative example attempts to form a rotor slot similar to that of the present embodiment, that is, a slot in which the distance between opposing surfaces widens toward the bottom of the slot, by one processing.

For this purpose, the cutting tool 3 has a rotationally symmetrical part 3a that is a rotationally symmetrical part with respect to the rotational center axis Y, and a protruding part 3b that projects to one side from the rotationally symmetrical part 3a. Ideally, the desired rotor slot should be formed by moving such a cutting tool 3 in the axial direction from the axial outside of the rotor core part 13 while rotating.

However, the cutting tool 3 is eccentric around the axis, and as a result, the base of the tooling tool 3 has to be thinner than the cutting part of the tooling tool 3, making it difficult to continue stable cutting. difficult.

On the other hand, in the method for forming the rotor slot 70 according to the present embodiment, it is possible to ensure that both the first groove cutting tool 81 and the second groove cutting tool 82 have a sufficient thickness at the base relative to the cutting portion. Moreover, since it is not eccentric, stable cutting is possible.

In addition, in the case of the present embodiment, by using two types of cutting tools, the first groove cutting tool 81 and the second groove cutting tool 82, the radius of curvature of the first groove connecting surface 71c, where bending stress is concentrated, is The radius of curvature can be set to be sufficiently large and different from that of the connecting portion 72c.

As described above, in this embodiment, by forming the rotor slots 70 at an angle with respect to the radial direction, a decrease in efficiency can be suppressed, and the first groove portion connection on the side where bending stress is concentrated is suppressed. By setting the radius of curvature of the surface 71c to a sufficiently large radius, structural soundness can be ensured.
Furthermore, by using two types of bits, stable machining is possible.

[Other embodiments]
Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. Furthermore, the embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. The embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

3...Bite, 3a...Rotationally symmetrical part, 3b...Protrusion part, 10...Rotor, 11...Rotor shaft, 12...Slim diameter part, 13...Rotor core part, 13a...Rotor teeth, 15...Secondary conductor, 16... Short circuit ring, 19... Gap, 20... Stator, 21... Stator core, 21a... Stator slot, 22... Stator winding, 31... Bearing, 32... Bearing bracket, 40... Frame, 70... Rotor Slot, 71...first groove, 71a...first groove side surface, 71b...first groove bottom surface, 71c...first groove connection surface, 72...second groove section, 72a...second groove side surface, 72b...second groove bottom surface, 72c...Second groove connection surface, 80...Groove machining device, 81...First groove cutting tool, 81a...Side part, 81b...Bottom part, 81c...Connection part, 82...Second groove cutting tool, 82a...Side part, 82b ...bottom, 82c...connection section, 85...rotary drive section, 100...rotating electric machine

Claims (5)

Extending in the axial direction and rotating shaftofa shaft portion rotatably supported around the
They are formed integrally with the shaft portion, have a larger diameter than the shaft portion, and are spaced apart from each other in the circumferential direction.Saida cylindrical rotor core portion in which a plurality of rotor slots extending in the axial direction are formed;
a plurality of electrical conductors passing through the rotor slots;
A block rotor having
multiplenumber ofSaidEach of the rotor slots is
a first side surface that is inclined at a first inclination angle with respect to a virtual plane that includes the rotation axis and extends in the radial direction; a first bottom surface that connects the first side surface and the first bottom surface; 1 connection surface,
a second side surface that is inclined at a second inclination angle with respect to the virtual plane, a second bottom surface, and a second connection surface that connects the second side surface and the second bottom surface;
has
the second inclination anglebutsmaller than the first inclination angleand the width at the bottom is larger than the width at the outer surface of the rotor core.
A block rotor characterized by: The block rotor according to claim 1, wherein a radius of curvature of the first connecting surface is larger than a radius of curvature of the second connecting surface. A block rotor according to claim 1 or 2,
A cylindrical stator core provided on the radially outer side of the rotor core portion, and a plurality of cylindrical stator cores formed on the radially inner surface of the stator core at intervals in the circumferential direction and extending in the axial direction. a stator having a stator winding passing through the interior of the stator slot;
two bearings that support the block rotor on both sides of the shaft portion in the axial direction with the rotor core portion in between;
A rotating electrical machine characterized by comprising: a shaft portion extending in the axial direction and rotatably supported around a rotation axis ; A cylindrical rotor core portion in which a plurality of rotor slots extending in the axial direction are formed , and the rotor core portion penetrates through the plurality of rotor slots and is coupled to each other on both outer sides of the rotor core portion in the axial direction. A method for forming rotor slots forming a plurality of rotor slots extending in the axial direction and spaced apart from each other in the circumferential direction in a block rotor having a plurality of electrical conductors, the method comprising:
a first side surface that is inclined at a first inclination angle with respect to a virtual plane that includes the rotation axis and extends in the radial direction; a first bottom surface; and a first side surface that connects the first side surface and the first bottom surface. a first groove machining step of machining a first groove having a connecting surface;
A first side surface having a second side surface inclined at a second inclination angle with respect to the virtual plane, a second bottom surface, and a second connection surface connecting the second side surface and the second bottom surface. a second groove machining step for machining the groove;
has
Each of the plurality of rotor slots has a second inclination angle smaller than the first inclination angle and a bottom width larger than the width at the outer surface of the rotor core.
A rotor slot forming method characterized by: 5. The rotor slot forming method according to claim 4, wherein a radius of curvature of the second connecting surface is larger than a radius of curvature of the first connecting surface.

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