CN111555489A

CN111555489A - Rotating electrical machine and elevator hoist system

Info

Publication number: CN111555489A
Application number: CN202010061015.4A
Authority: CN
Inventors: 郡大祐; 原豪希; 远藤雅章; 饭塚元信
Original assignee: Hitachi Industrial Products Ltd
Current assignee: Hitachi Industrial Products Ltd
Priority date: 2019-02-08
Filing date: 2020-01-19
Publication date: 2020-08-18
Also published as: JP2020129890A

Abstract

The invention provides a rotating electrical machine capable of suppressing performance reduction and reducing eddy current loss of a rotor, and a hoist system for an elevator including the rotating electrical machine. A rotating electric machine (100) according to the present invention includes: a rotor (1) having a rotor core (3), a plurality of permanent magnets (5), and a rotating shaft (8); and a cylindrical stator (2) disposed radially outside the rotor (1). On the surface of the rotor core (3), a plurality of permanent magnet (5) groups that are arranged in the axial direction and in contact with each other are arranged in the circumferential direction. The portion where the plurality of permanent magnets (5) arranged in the axial direction are in contact with each other is defined as an abutting portion (10). The rotor core (3) has a recess (11) extending in the circumferential direction at a position on the surface portion that faces the adjacent portion (10) of the permanent magnet (5) in the radial direction.

Description

Rotating electrical machine and elevator hoist system

Technical Field

The present invention relates to a rotating electrical machine including a rotor and a stator, and a hoisting machine system for an elevator including the rotating electrical machine.

Background

An induction motor has been conventionally used as a rotating electric machine for an elevator, but in recent years, a permanent magnet type rotating electric machine that can be made smaller, lighter, and more efficient has been used with the price reduction of permanent magnets and the spread of high-performance inverters.

Since elevators are used by people like automobiles and electric trains, they are required to have good riding comfort. One of the factors that deteriorate ride comfort of an elevator is Torque ripple (Torque ripple) generated from a rotating electric machine. In particular, in an elevator system used at high speed and under a large load, a rotating electric machine is connected to a transmission case, and reliability of the transmission case is lowered due to torque pulsation. In order to reduce torque ripple, the rotor has a surface magnet type structure in which permanent magnets are disposed on the surface of a rotor core.

The rotation speed of the rotating motor itself is hundreds of minutes due to the connection with the gear^-1Is low as a rotating electrical machine. The output of the rotating electrical machine depends on the product of the angular velocity and the torque. A rotating electrical machine with a low rotational speed requires a large torque to obtain an output equivalent to that of a rotating electrical machine with a high rotational speed, and a rotor needs to have a large diameter to obtain a large torque. Generally, a rotor and a stator constituting a rotating electric machine are configured by laminating electromagnetic steel sheets. However, it is difficult to form a large-diameter rotor and stator by laminating circular electromagnetic steel sheets. Therefore, in general, the stator is formed by laminating divided electromagnetic steel plates. Since the rotor is a rotating body, it is difficult to laminate the divided electromagnetic steel plates like a stator in terms of reliability. Therefore, the rotor is preferably constituted by a block core.

When the rotor is formed of a block core, an eddy current loss occurs unlike a structure formed by stacking electromagnetic steel plates. A rotor formed of a block core has problems of efficiency reduction and temperature increase due to eddy current loss. Therefore, a structure for reducing eddy current loss has been studied for a rotor formed of a block core.

Patent documents

1 and 2 describe examples of conventional rotating electric machines in which eddy current loss of a rotor is reduced. Patent document 1 describes a brushless motor in which a plurality of slots are provided on a surface of a rotor core to which permanent magnets are fixed, the rotor core being made of a sintered material obtained by sintering fixed magnetic powder. Patent document 2 describes a rotating electrical machine in which a plurality of slots extending in the circumferential direction and arranged in the axial direction are provided on a magnet attachment surface of a rotor core.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012 and 95476

Patent document 2: japanese patent laid-open No. 2007-74776

Disclosure of Invention

Technical problem to be solved by the invention

The brushless motor described in patent document 1 as a rotating electric machine reduces eddy current loss by providing a plurality of grooves at positions facing the permanent magnets on the surface of the rotor core to which the permanent magnets are fixed. The plurality of grooves are effective for reducing eddy current loss, but may reduce the performance of the rotating electrical machine.

In a surface magnet type rotor in which permanent magnets are arranged on the surface of a rotor core, it is disadvantageous that an air portion such as a groove exists in a magnetic path of magnetic flux generated from the permanent magnets in addition to a gap between the rotor and a stator. This is because the air in the magnetic circuit becomes a magnetic resistance with respect to the magnetic flux, and the performance of the rotating electric machine is degraded. In addition, when a plurality of grooves are provided on the surface of the rotor core to which the permanent magnets are fixed as in the rotating electrical machine described in patent document 1, the grooves are also provided at positions facing the center portions of the permanent magnets. The axial magnetic flux density distribution of the permanent magnet is maximized at the center portion of the permanent magnet. Therefore, in the rotating electrical machine described in patent document 1, since the grooves are provided at the positions where the magnetic flux density distribution of the permanent magnets becomes maximum, there is a concern that the performance (for example, the voltage and the torque) of the rotating electrical machine may be greatly reduced. In addition, when the number of slots is large, although the effect of reducing the eddy current loss is large, the performance of the rotating electrical machine is also greatly reduced.

In the rotating electric machine described in patent document 2, a plurality of slots arranged in the axial direction are provided on the magnet mounting surface of the rotor core, thereby reducing eddy current loss. The plurality of grooves are not provided at positions opposed to the permanent magnets. However, in a rotor in which a plurality of permanent magnets are arranged in the axial direction, when a plurality of slots are provided in the magnet attachment surface of the rotor core so as to be arranged in the axial direction, there is a possibility that the number of slots is reduced to reduce the effect of reducing the eddy current loss, and a possibility that the performance of the rotating electrical machine is significantly reduced by providing slots also at a position facing the center portion of the permanent magnet as in the rotating electrical machine described in patent document 1.

As described above, there is a Trade-off (Trade off) between the effect of reducing eddy current loss due to the slots provided in the rotor core and the performance of the rotating electric machine. Therefore, in order to reduce the eddy current loss of the rotor while suppressing the performance degradation of the rotating electrical machine, it is important to determine the position of the groove (recess) provided in the rotor core in accordance with the characteristics of the magnetic flux density distribution of the permanent magnet.

The purpose of the present invention is to provide a rotating electrical machine capable of reducing the eddy current loss of a rotor while suppressing the performance degradation, and an elevator hoisting machine system including the rotating electrical machine.

Technical solution for solving technical problem

The rotating electric machine of the present invention includes: a rotor having a rotor core, a plurality of permanent magnets, and a rotating shaft; and a cylindrical stator provided radially outside the rotor, wherein the plurality of permanent magnet groups arranged in the axial direction and in contact with each other are arranged in the circumferential direction on the surface portion of the rotor core. A portion where the plurality of permanent magnets arranged in the axial direction are in contact with each other is made an abutting portion. The rotor core has a recess extending in the circumferential direction at a position of the surface portion that is radially opposed to the abutting portion of the permanent magnet.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a rotating electrical machine capable of reducing an eddy current loss of a rotor while suppressing a decrease in performance, and an elevator hoisting machine system including the rotating electrical machine.

Drawings

Fig. 1 is a cross-sectional view of a rotating electric machine according to embodiment 1 of the present invention, the cross-sectional view being perpendicular to the axial direction.

Fig. 2 is a diagram showing a magnetic flux density distribution in the axial direction of the magnet.

Fig. 3 is a cross-sectional view perpendicular to the axial direction showing the rotor core and the magnets of 7 poles of the rotor.

Fig. 4 is a sectional view of the rotor core and the magnet at a section line a-a of fig. 3.

Fig. 5 is an enlarged view of the rotor core and the magnets shown in fig. 4. (the position of the center in the axial direction of the recess is different from the position of the adjacent part in the axial direction of the magnet.)

Fig. 6 is an enlarged view of the rotor core and the magnets shown in fig. 4. (the position of the axial center of the recess coincides with the axial position of the adjacent part of the magnet.)

Fig. 7 is a diagram showing a difference in distribution of magnetic flux density due to a difference in shape of the permanent magnet.

Fig. 8 is a cross-sectional view of the rotor and stator of the rotating electric machine according to embodiment 2 of the present invention similar to fig. 4.

Fig. 9 is a graph showing a relationship between the radial depth h of the recess and eddy current loss of the magnet and the rotor core.

Fig. 10 is a sectional view similar to fig. 4 of the rotor core and the magnet of the rotating electric machine according to embodiment 3 of the present invention.

Fig. 11A is a sectional view similar to fig. 3 of the rotor core and the magnet of the rotating electric machine according to embodiment 4 of the present invention.

Fig. 11B is an enlarged view of a portion a of fig. 11A.

Fig. 12 is a graph showing a relationship between the radial height of the projection and the eddy current loss of the rotor core.

Fig. 13 is a sectional view similar to fig. 3 of the rotor core and the magnet of the rotating electric machine according to embodiment 5 of the present invention.

Fig. 14 is a sectional view of the rotor core and the magnets at the section line B-B of fig. 13.

Fig. 15 is a cross-sectional view of the rotor core and magnets at section line C-C of fig. 13.

Fig. 16 is a sectional view of the rotor core and the magnets at a cut-off line C-C of fig. 13 in a structure in which the rotor core has a recess extending over the entire circumference in the circumferential direction.

Fig. 17A is a view showing a rotor core and a magnet of a rotating electric machine according to example 6 of the present invention, and is a sectional view similar to fig. 15.

Fig. 17B is a view showing a rotor core and a magnet of a rotating electric machine according to embodiment 6 of the present invention, and is a view when the rotor core and the magnet of fig. 17A are viewed from the direction of arrow D.

Fig. 18 is a diagram showing an elevator hoisting machine system according to embodiment 7 of the present invention.

Fig. 19 is a diagram showing another elevator hoisting machine system according to embodiment 7 of the present invention.

Fig. 20 is a sectional view similar to fig. 3 of a rotor core and a magnet of another rotating electric machine according to embodiment 3 of the present invention.

Detailed Description

The invention provides a rotating electrical machine which can reduce the eddy current loss of a rotor and can inhibit the performance of the rotating electrical machine from being reduced. The rotor is preferably formed of a block core, and has a surface magnet type structure in which a permanent magnet is disposed on the surface of the rotor core. In the rotating electric machine according to the present invention, a plurality of sets of permanent magnets adjacent to each other in the axial direction are provided in the circumferential direction on the surface of the rotor core.

A rotating electric machine and an elevator hoisting machine system according to an embodiment of the present invention will be described below with reference to the drawings. In the drawings used in the present specification, the same or corresponding components are denoted by the same reference numerals, and repeated description of these components may be omitted. In the following description, the permanent magnet may be simply referred to as "magnet".

[ example 1]

Fig. 1 is a cross-sectional view of a rotating electric machine 100 according to embodiment 1 of the present invention, the cross-sectional view being perpendicular to the axial direction. Fig. 1 shows a portion 1/4 in the circumferential direction of the rotating electric machine 100. The rotating electric machine 100 has an output of several hundred kW and a rotation speed of several hundred min^-1A rotary electric machine (e.g., a motor) of a class, which is mainly installed in a hoisting machine for an elevatorThe system is especially for high speed and heavy load elevator.

In the rotating electric machine 100, a direction in which the rotating shaft extends is referred to as an "axial direction", a rotating direction of the rotating shaft is referred to as a "circumferential direction", and a radial direction of the rotating shaft is referred to as a "radial direction".

The rotating electric machine 100 includes a rotor 1 and a stator 2. The rotor 1 includes a rotor core 3, a permanent magnet 5 provided to the rotor core 3, and a rotating shaft (draft) 8 extending in the axial direction. The stator 2 is cylindrical, is disposed radially outside the rotor 1, and includes a stator core 4, slots 15, coils 6, and teeth 16. The slots 15 are provided in the inner peripheral portion of the stator core 4 and house the coils 6. The teeth 16 are located between 2 grooves 15 adjacent to each other. A gap 7 is provided between the rotor 1 and the stator 2. The interval of 2 slots 15 adjacent to each other along the inner peripheral portion of the stator core 4 is referred to as a slot pitch s.

Fig. 3 is a cross-sectional view perpendicular to the axial direction showing the rotor core 3 and the magnets 5 of the 7 poles of the rotor 1. The rotor 1 is a surface magnet type rotor in which a plurality of magnets 5 are provided on the surface portion of the rotor core 3. On the surface portion of the rotor core 3, a plurality of sets of magnets 5 that are arranged in the axial direction and contact each other are arranged in the circumferential direction. The magnet 5 is shaped like a rectangular parallelepiped, that is, the magnet 5 is a flat plate composed of 6 planes.

Fig. 4 is a sectional view of rotor core 3 and magnet 5 at a section line a-a of fig. 3. A plurality of magnets 5 arranged axially and adjacent to each other are provided on a surface portion (radial surface portion) of the rotor core 3. A portion where the plurality of magnets 5 aligned in the axial direction contact each other is referred to as an abutting portion 10.

As described above, in a rotating electrical machine requiring a large torque to obtain a desired output, the rotor 1 is large in size and requires a large magnet. However, from the viewpoint of productivity of the magnet, it is preferable to use a plurality of magnets 5 in contact with each other for the rotor 1, as compared with using a large magnet for the rotor 1. In order to reduce the eddy current loss generated in the magnets, it is also effective to use a plurality of magnets 5 in contact with each other in the rotor 1.

The rotor core 3 is provided with a recess 11 at a position radially opposed to the abutting portion 10 of the magnet 5. The recess 11 is a void portion (i.e., a groove) extending in the circumferential direction, and is provided in the surface portion of the rotor core 3. The size and shape of the recess 11 can be determined arbitrarily. The circumferential length of the recess 11 can be arbitrarily determined, and may be, for example, the same as the circumferential length of the magnet 5 or may be a length extending over the entire circumference of the rotor core 3 in the circumferential direction (described in embodiment 5). Among them, the shape of the recess 11 is preferably symmetrical in the axial direction with respect to the center in the axial direction of the recess 11.

Since the recess 11 becomes a resistor in the current path of the generated eddy current, the eddy current hardly flows through the rotor core 3. Therefore, in the rotor 1, the rotor core 3 has the recess 11, so that the eddy current loss can be reduced.

Fig. 2 is a diagram showing the magnetic flux density distribution in the axial direction of the magnet 5. In fig. 2, the magnetic flux of the magnet 5 is indicated by an arrow, and the length of the arrow indicates the magnitude of the magnetic flux density. As shown in fig. 2, the magnetic flux density of the magnet 5 is smaller at the end portions (corner portions) of the magnet 5 in the axial direction than at the center portion of the magnet 5 in the axial direction (this is the same in the case where no magnetic substance is present around the magnet 5 before the magnet 5 is provided on the rotor 1). In other words, the end portions of the magnet 5 in the axial direction can be regarded as not functioning as the magnet 5 as compared with the central portion in the axial direction.

Therefore, even if the recess 11 serving as a magnetic resistance is provided at a position radially opposed to the abutting portion 10 which is an end portion in the axial direction of the magnet 5, the influence exerted on the magnetic flux of the entire magnet 5 is smaller than in the case where the recess 11 is provided at a position radially opposed to the center portion in the axial direction of the magnet 5. For this reason, the position where the recess 11 is provided in the rotor core 3 is preferably a position radially opposed to the adjacent portion 10 of the plurality of magnets 5 arranged in the axial direction. By providing the recess 11 at such a position, the eddy current loss of the rotor 1 can be reduced while suppressing the performance degradation of the rotating electric machine 100.

Fig. 5 is an enlarged view of the rotor core 3 and the magnet 5 shown in fig. 4, and shows the recess 11 and the abutting portion 10. In the configuration shown in fig. 5, the position of the center 11a in the axial direction of the recess 11 is different from the position in the axial direction of the abutting portion 10 of the magnet 5. In this configuration, the magnetic resistance to the magnetic flux is not uniform with respect to the plurality of magnets 5 arranged in the axial direction. When the magnetic resistance is not uniform with respect to the plurality of magnets 5, the magnetic flux density distribution of the magnets 5 also becomes non-uniform, and a ripple component increases in voltage, current, and torque, thereby increasing vibration, noise, and loss, which becomes a factor of degrading the performance of the rotating electric machine 100.

Fig. 6 is an enlarged view of the rotor core 3 and the magnet 5 shown in fig. 4, and shows the recess 11 and the abutting portion 10. In the configuration shown in fig. 6, the position of the center 11a in the axial direction of the recess 11 coincides with the position in the axial direction of the abutting portion 10 of the magnet 5. When the recess 11 is provided at such a position, the magnetic resistance to the magnetic flux becomes uniform with respect to the plurality of magnets 5 arranged in the axial direction, and the performance of the rotating electric machine 100 can be effectively suppressed from being degraded. Therefore, the position of the axial center 11a of the recess 11 preferably coincides with the axial position of the abutting portion 10 of the magnet 5.

In the present embodiment, the magnet 5 has a flat plate shape, and the number of poles of the rotor 1 is 56. In the surface magnet type rotor 1, the torque ripple is easily suppressed even when the flat plate type magnet 5 is used for the rotor having a large number of poles. For example, when the flat plate-shaped magnet 5 is used for a rotor having 4 or 6 poles, the rotor itself has a square-prism or hexagonal-prism shape, and therefore, the magnetic flux density distribution changes greatly when the rotor rotates, and the torque ripple increases. In order to suppress torque ripple, a D-shaped permanent magnet or a tile-shaped permanent magnet is generally used for a surface magnet type rotor.

Fig. 7 is a diagram showing a difference in distribution of magnetic flux density due to a difference in shape of the permanent magnet. Fig. 7 shows the respective shapes and the distribution of the magnetic flux density in the circumferential direction for the flat permanent magnet 5, the D-shaped permanent magnet 12, and the shoe-shaped permanent magnet 13 included in the rotor 1 of the rotating electrical machine 100 according to the present embodiment. The D-shaped permanent magnet 12 has a curved surface in which the radially outer surface is curved radially outward, and the radially inner surface is a flat surface. Both the radially outer surface and the radially inner surface of the shoe-shaped permanent magnet 13 are curved surfaces that curve radially outward. As shown in fig. 7, the difference in the shape of the permanent magnet appears in the distribution of the magnetic flux density. In the flat plate-type permanent magnet 5, the magnetic flux density exhibits substantially the same distribution in the circumferential direction. In the D-shaped permanent magnet 12 and the tile-shaped permanent magnet 13, the magnetic flux density exhibits a distribution that is the largest in the center portion in the circumferential direction of the

permanent magnets

12, 13.

In the rotating electrical machine 100 of the present embodiment, since the number of poles of the rotor 1 is large, even if the flat plate-type permanent magnets 5 are used, the change in the magnetic flux density distribution when the rotor 1 rotates is small, and torque ripple can be suppressed. In the rotating electric machine 100 of the present embodiment, torque ripple can be suppressed even when the D-shaped permanent magnet 12 or the shoe-shaped permanent magnet 13 is used.

Therefore, in the rotating electrical machine 100 of the present embodiment, regardless of the shape of the permanent magnet provided on the rotor core 3, by providing the rotor core 3 with the recess 11 at a position radially opposed to the abutting portion 10 of the plurality of permanent magnets arranged in the axial direction, it is possible to suppress torque ripple, suppress a decrease in performance of the rotating electrical machine 100, and reduce the eddy current loss of the rotor 1.

The rotor core 3 is preferably formed of a casting such as a block core. When the rotor core 3 is formed of a casting, the recess 11 is easily formed as compared with the rotor core 3 formed of an electromagnetic steel plate, and the number of assembling steps can be reduced, thereby achieving an effect of reducing the cost. Although the number of poles of rotating electric machine 100 of the present embodiment is 56 and the number of slots 15 is 72, the present embodiment can be applied to a rotating electric machine having a different number of poles and the number of slots 15, and the same effects as the present embodiment can be obtained. The coil 6 may be formed by concentrated winding or by other winding methods.

[ example 2]

Fig. 8 is a sectional view similar to fig. 4 of rotor 1 and stator 2 of rotating electric machine 100 according to embodiment 2 of the present invention. The recess 11 provided in the rotor core 3 has a radial depth h.

In the present embodiment, a relationship between the radial depth h of the recess 11 and the eddy current loss of the magnet 5 and the rotor core 3 will be described.

Fig. 9 is a graph showing a relationship between the radial depth h of the recess 11 and eddy current loss of the magnet 5 and the rotor core 3. The graph is obtained by electromagnetic field analysis using the rotating electric machine 100 of the present embodiment as a model. The horizontal axis represents the ratio of the radial depth h to the slot pitch s (radial depth h/slot pitch s), and the vertical axis represents the eddy current loss of the magnet 5 and the rotor core 3. The slot pitch s is expressed as (inner diameter of the stator 2 x pi/number of slots 15).

In the graph of fig. 9, the value of the eddy current loss between the magnet 5 and the rotor core 3 when (radial depth h/slot pitch s) is 0 is normalized to 1.0. When (radial depth h/slot pitch s) is 0, the radial depth h is 0, and the rotor core 3 does not have the recess 11.

As shown in fig. 9, when (radial depth h/groove pitch s) increases from 0 to around 0.04, the eddy current loss sharply decreases. When (radial depth h/groove pitch s) exceeds 0.04 and increases to around 0.08, the eddy current loss slowly decreases. When (radial depth h/groove pitch s) exceeds 0.1, the eddy current loss hardly changes.

From the relationship shown in fig. 9, in order to reliably reduce the eddy current loss, it can be said that the case where (radial depth h/groove pitch s) is 0.1 or more is effective. That is, the radial depth h of the recess 11 is preferably 0.1s or more. This is because the influence of the slot pitch s on the eddy current loss is large.

In order to reduce the eddy current loss, (radial depth h/groove pitch s) ≧ 0.1 is preferable. The value of the radial depth h may be determined by the value of the groove pitch s, and does not have to exceed a required value. When the recess 11 is formed in the rotor core 3, the rotor core 3 may be machined so that the recess 11 having the required minimum depth h is formed in the rotor core 3.

By utilizing the relationship (radial depth h/groove pitch s) ≥ 0.1 obtained from fig. 9, the radial depth h of the recess 11 can be set to an appropriate depth. This can shorten the time (machining time) for forming the recess 11, and can sufficiently reduce the eddy current loss.

The recess 11 provided in the rotor core 3 can reduce eddy current loss generated in the rotor core 3 and also eddy current loss generated in the magnet 5. Although the pulsation of the magnetic flux is also transmitted to the magnet 5 itself, the recess 11 is positioned to face the magnet 5 in the radial direction, and therefore becomes a magnetic resistance with respect to the pulsation of the magnetic flux transmitted to the magnet 5. Therefore, the recess 11 can also reduce eddy current loss generated by the magnet 5.

[ example 3]

Fig. 10 is a sectional view similar to fig. 4 of rotor core 3 and magnet 5 of rotating electric machine 100 according to embodiment 3 of the present invention.

In rotating electric machine 100 of the present embodiment, rotor core 3 is provided with recesses 11 at positions radially opposed to adjacent portions 10 of magnets 5 as in embodiment 1, and further, recesses 11 are provided at positions other than the positions. When the recess 11 is provided at a position other than the position shown in example 1, the eddy current loss of the rotor 1 can be further reduced.

In the example shown in fig. 10, the recess 11 is provided at a position facing the adjacent portion 10 of the magnet 5 in the radial direction and at a position facing the magnet 5 except the adjacent portion 10 in the radial direction on the surface portion of the rotor core 3. For 1

magnet

5, 3 recesses 11 are provided at positions radially opposed to the magnet 5 except the abutting portion 10. The number of the recesses 11 provided at positions radially opposed to the 1 magnet 5 can be determined by the amount of eddy current loss reduction.

The recess 11 may be provided at a position not radially opposed to the magnet 5, in addition to a position radially opposed to the abutting portion 10 of the magnet 5 on the surface portion of the rotor core 3. The position not opposed to the magnet 5 in the radial direction is, for example, a position opposed to a position between 2 magnets 5 adjacent to each other in the circumferential direction in the radial direction. The number of the recesses 11 provided at positions not opposed to the magnets 5 in the radial direction can be determined by the amount of eddy current loss reduction.

Fig. 20 is a sectional view similar to fig. 3 of rotor core 3 and magnet 5 of another rotating electric machine 100 according to embodiment 3 of the present invention. Fig. 20 is a cross-sectional view showing a cross-section perpendicular to the axial direction at a position not passing through the abutting part 10 of the magnet 5. The rotor core 3 is provided with a recess 11 at a position of the surface portion which is radially opposed to the abutting portion 10 of the magnet 5 and a position which is radially opposed to a position between 2 magnets 5 adjacent to each other in the circumferential direction.

When a large number of recesses 11 are provided in the rotor core 3 as in the present embodiment, the axial intervals between the recesses 11 are preferably constant. If the axial intervals of the recesses 11 are different from each other, the magnetic resistance of the magnetic flux with respect to the magnet 5 becomes uneven with respect to the plurality of magnets 5 arranged in the axial direction, and as described in embodiments 1 to fig. 5, the magnetic flux density distribution of the magnet 5 also becomes uneven due to the magnetic resistance of the recesses 11. Due to this influence, the ripple component in the voltage, current, and torque increases, and vibration, noise, and loss increase, and the performance of the rotating electric machine 100 may be degraded. Therefore, the axial intervals of the recesses 11 are preferably constant.

When a large number of recesses 11 are provided in the rotor core 3, the effect of reducing the eddy current loss is large, but there is a concern that the performance of the rotating electrical machine 100 is degraded. Therefore, the number of the recesses 11 is preferably large in a range where the rotating electric machine 100 can maintain required performance.

In the rotating electrical machine 100 of the present embodiment, by providing the rotor core 3 with more recesses 11, it is possible to suppress a decrease in performance of the rotating electrical machine 100 and to more effectively reduce the eddy current loss of the rotor 1.

[ example 4]

Fig. 11A is a sectional view similar to fig. 3 of rotor core 3 and magnet 5 of rotating electric machine 100 according to embodiment 4 of the present invention. Fig. 11B is an enlarged view of a portion a of fig. 11A, and is a view showing a space between 2 magnets 5 adjacent to each other in the circumferential direction.

In the rotating electrical machine 100 of the present embodiment, the rotor core 3 has the projections 9 between 2 magnets 5 (between magnetic poles) adjacent to each other in the circumferential direction. The projection 9 is made of a magnetic material (e.g., iron as in the case of the rotor core 3), and projects radially outward from the surface of the rotor core 3. The outer end of the projection 9 is located inward of the outer end of the magnet 5 in the radial direction. That is, the projection 9 does not project radially outward beyond the magnet 5, and the magnet 5 projects radially outward beyond the projection 9. The projection 9 is in surface contact with the circumferential end of the magnet 5.

By the projection 9, when the magnet 5 is attached to the rotor core 3, the circumferential position of the magnet 5 can be determined, and the magnet 5 can be fixed so that the position of the magnet 5 does not deviate in the circumferential direction, so that the productivity of the rotor 1 can be improved. Further, since the projection 9 is in surface contact with the magnet 5, concentrated stress is less likely to occur in the magnet 5, and the reliability of the magnet 5 can be improved.

Here, the relationship between the radial height of the projection 9 and the eddy current loss will be described.

Fig. 12 is a graph showing a relationship between the radial height of the projection 9 and the eddy current loss of the rotor core 3. The graph is obtained by electromagnetic field analysis using the rotating electric machine 100 of the present embodiment as a model. The horizontal axis represents the length from the rotation center of the rotor 1 to the end portion on the radially outer side of the projection 9 as the radial height of the projection 9. The vertical axis represents the eddy current loss of rotor core 3. The radial height of the protrusion 9 on the horizontal axis is normalized to 1.0 when the rotor core 3 does not have the protrusion 9. The value of the eddy current loss of the rotor core 3 on the vertical axis is also normalized to 1.0 in the case where the rotor core 3 does not have the projection 9.

As shown in fig. 12, when the rotor core 3 does not have the projection 9 (when the radial height of the projection 9 is 1.0), the eddy current loss of the rotor core 3 can be reduced most. However, as described above, by providing the projection 9 on the rotor core 3, the productivity of the rotor 1 can be improved. Accordingly, in view of reduction in eddy current loss of the rotor 1 and improvement in productivity of the rotor 1, it is preferable to make the radial height of the projection 9 as small as possible.

When the position of the outer end of the projection 9 in the radial direction is located outward of the position of the outer end of the magnet 5 (that is, when the projection 9 projects radially outward from the magnet 5), the magnetic flux of the magnet 5 flowing into the gap 7 is concentrated on the projection 9. At this time, since the projection 9 is formed of a magnetic material, the magnetic flux becomes saturated, and the magnetic flux density becomes high. When the magnetic flux of the projection 9 is saturated, the eddy current loss of the rotor core 3 is not easily changed, and the magnetic flux is saturated.

When the position of the outer end of the projection 9 in the radial direction is located inward of the position of the outer end of the magnet 5 (that is, when the projection 9 does not protrude outward in the radial direction from the magnet 5), the magnetic flux of the magnet 5 is not concentrated on the projection 9, and the eddy current loss of the rotor core 3 is likely to change, and can be reduced.

From the above, it is preferable that the position of the outer end of the projection 9 in the radial direction is located inward of the position of the outer end of the magnet 5 (that is, the projection 9 does not project outward in the radial direction from the magnet 5, and the magnet 5 projects outward in the radial direction from the projection 9).

The protrusion 9 may be made of a nonmagnetic material (e.g., stainless steel).

In the rotating electrical machine 100 of the present embodiment, by providing the rotor core 3 with the projection 9, it is possible to improve the productivity of the rotor 1, suppress a decrease in the performance of the rotating electrical machine 100, and more effectively reduce the eddy current loss of the rotor 1.

[ example 5]

Fig. 13 is a sectional view similar to fig. 3 of rotor core 3 and magnet 5 of rotating electric machine 100 according to embodiment 5 of the present invention. In the rotating electric machine 100 of the present embodiment, the rotor core 3 has the projections 9 between 2 magnets 5 (between magnetic poles) adjacent to each other in the circumferential direction, similarly to the rotating electric machine 100 of embodiment 4 (fig. 11A). In fig. 13, a cut-off line B-B passes through the circumferential center of the magnet 5, and a cut-off line C-C passes through the circumferential center of the protrusion 9.

Fig. 14 is a sectional view of rotor core 3 and magnet 5 at a section line B-B of fig. 13. As shown in fig. 14, the rotor core 3 has a plurality of projections 9 aligned in the axial direction. The plurality of projections 9 are provided intermittently in the axial direction.

As described in example 4 using fig. 12, when rotor core 3 does not have projection 9, the eddy current loss of rotor core 3 can be reduced. However, as described in embodiment 4, the productivity of the rotor 1 can be improved by providing the protrusions 9. In consideration of these circumstances, it is not necessary to provide the projections 9 continuously over the entire axial direction of the rotor core 3, and a plurality of projections 9 may be provided intermittently in the axial direction. By providing the plurality of projections 9 intermittently in the axial direction in the rotor core 3, it is possible to improve the productivity of the rotor 1, suppress a decrease in the performance of the rotating electrical machine 100, and effectively reduce the eddy current loss of the rotor 1.

Fig. 15 is a sectional view of rotor core 3 and magnet 5 at a section line C-C of fig. 13. As shown in fig. 15, the plurality of projections 9 are provided intermittently in the axial direction.

The position of the projection 9 is preferably adjacent to the abutting portion 10 of the magnet 5 (the position where the plurality of magnets 5 arranged in the axial direction contact each other) in the circumferential direction. That is, the axial position of the projection 9 is preferably the same as the axial position of the recess 11 described in embodiment 1 (see fig. 14). When the axial position of the projection 9 is such a position, the circumferential position can be determined and fixed by 1 projection 9 in the axial direction with respect to 2 magnets 5 adjacent in the axial direction. That is, the number of the projections 9 for fixing the magnet 5 can be reduced.

With such a configuration, the productivity of the rotor 1 can be improved, the performance of the rotating electrical machine 100 can be suppressed from being degraded, and the eddy current loss of the rotor 1 can be effectively reduced.

The recess 11 is shown in fig. 14 but not in fig. 15. This is because the recess 11 is not provided so as to extend along the entire circumference of the rotor core 3 in the circumferential direction, but is provided only in a portion where the magnet 5 is present.

Fig. 16 is a sectional view of the rotor core 3 and the magnet 5 at a cut-off line C-C of fig. 13 in a structure in which the rotor core 3 has the recess 11 extending over the entire circumference in the circumferential direction. Since the recess 11 extends over the entire circumference of the rotor core 3 in the circumferential direction, the recess 11 is also provided at a position where the projection 9 exists. Since the recess 11 is present, the protrusion 9 is divided into 2 pieces as shown in fig. 16.

In order to more effectively reduce the eddy current loss of the rotor 1, the recess 11 is preferably provided so as to extend over the entire circumference of the rotor core 3 in the circumferential direction. However, if the recess 11 is provided at a position where the projection 9 is present, the strength of the projection 9 is reduced, and the projection is likely to be deformed or broken, which may reduce the reliability of the rotor 1. Therefore, it is preferable to determine whether or not to provide the recess 11 over the entire circumference of the rotor core 3 in the circumferential direction, depending on the operating conditions and the usage environment of the rotating electric machine 100.

As described in embodiment 1 (the rotating electrical machine 100 configured such that the rotor core 3 does not have the projection 9), the circumferential length of the recess 11 can be determined arbitrarily. Therefore, even if the rotor core 3 does not have the projection 9, the recess 11 can be provided so as to extend over the entire circumference of the rotor core 3 in the circumferential direction.

[ example 6]

Fig. 17A and 17B are views showing rotor core 3 and magnet 5 of rotating electric machine 100 according to embodiment 6 of the present invention. Fig. 17A is a sectional view similar to fig. 15. Fig. 17B is a view of rotor core 3 and magnet 5 of fig. 17A viewed from the direction of arrow D.

In rotating electric machine 100 of the present embodiment, projection 9 is constituted by screw 14 provided on rotor core 3. The screw 14 may be formed of a magnetic material or a non-magnetic material. When the screws 14 are formed of a non-magnetic material such as stainless steel, the eddy current loss of the rotor 1 can be more effectively reduced.

[ example 7]

In embodiment 7 of the present invention, an example in which the rotating electric machine 100 according to embodiments 1 to 6 of the present invention is applied to an elevator hoisting machine system will be described. In the elevator hoisting machine system of the present embodiment, the eddy current loss of the rotor 1 can be reduced while suppressing the performance degradation of the rotating electric machine 100.

Fig. 18 is a diagram showing an elevator hoisting machine system according to embodiment 7 of the present invention. The elevator hoisting machine system of the present embodiment includes a rotating electric machine 100, a hoisting machine 22, and a coupling 23. The rotating electric machine 100 is the rotating electric machine 100 according to any one of embodiments 1 to 6. The hoisting machine 22 has a sheave. The rotating electric machine 100 is connected to a sheave of the hoisting machine 22 via a coupling 23 to drive the hoisting machine 22. In the rotating electric machine 100 shown in fig. 18, bearings 17 that support the rotating shaft 8 are provided at both axial ends of the rotating electric machine 100.

Fig. 19 is a diagram showing another elevator hoisting machine system according to embodiment 7 of the present invention. The rotating electric machine 100 is connected to a sheave of the hoisting machine 22 via a coupling 23 to drive the hoisting machine 22, and the bearing 17 is provided at only one axial end. That is, the rotating electric machine 100 shown in fig. 19 does not have the bearing 17 on the side close to the hoisting machine 22 (direct connection side) in the axial direction, and has only the bearing 17 on the side far from the hoisting machine 22. The hoisting machine system for an elevator shown in fig. 19 is configured such that the hoisting machine 22 supports one axial end side of the rotating electric machine 100. By adopting such a configuration, the size (axial length) of the elevator hoisting machine system can be reduced. Since the bearing 17 is not provided on the one end side in the axial direction, an effect of reducing the number of components of the rotating electric machine 100 can also be obtained.

The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the above-described embodiments have been described in detail to explain the present invention easily and understandably, and the present invention is not limited to the embodiments having all the configurations described. A part of the structure of one embodiment can be replaced with the structure of another embodiment. The structure of one embodiment can also be added to the structure of the other embodiment. For a part of the structures of the embodiments, other structures can be omitted, or added/replaced.

Description of reference numerals

1 … rotor, 2 … stator, 3 … rotor core, 4 … stator core, 5 (flat plate type) … permanent magnet, 6 … coil, 7 … gap, 8 … rotating shaft, 9 … protrusion, 10 … adjacent part, 11 … recess, 11a … axial center, 12 … D-shaped permanent magnet, 13 … tile-shaped permanent magnet, 14 … screw, 15 … slot, 16 … tooth, 17 … bearing, 22 … traction machine, 23 … coupling, 100 … rotating electric machine.

Claims

1. A rotating electrical machine, characterized by comprising:

a rotor having a rotor core, a plurality of permanent magnets, and a rotating shaft; and

a cylindrical stator disposed radially outside the rotor,

a plurality of permanent magnet groups arranged in an axial direction and contacting each other are arranged in a circumferential direction on a surface portion of the rotor core,

a portion where the plurality of permanent magnets arranged in the axial direction are in contact with each other is made an abutting portion,

the rotor core has a recess extending in the circumferential direction at a position of the surface portion that is radially opposed to the abutting portion of the permanent magnet.

2. The rotating electric machine according to claim 1, characterized in that:

the position of the center of the recess of the rotor core in the axial direction coincides with the position of the abutting section of the permanent magnet in the axial direction.

3. The rotating electric machine according to claim 1, characterized in that:

the permanent magnet is in a cuboid shape.

4. The rotating electric machine according to claim 1, characterized in that:

the stator includes a stator core having a coil-receivable slot formed in an inner peripheral portion thereof, and the recess of the rotor core has a depth h in a radial direction of 0.1s or more when s represents an inner diameter × pi of the stator/the number of slots.

5. The rotating electric machine according to claim 1, characterized in that:

the rotor core has the recessed portion at a position of the surface portion facing the abutting portion of the permanent magnet in the radial direction and at a position other than the abutting portion facing the permanent magnet in the radial direction.

6. The rotating electric machine according to claim 1, characterized in that:

the rotor core has the recessed portion at a position of a surface portion that is opposed to the abutting portion of the permanent magnet in a radial direction and at a position that is opposed to a position between 2 permanent magnets that are adjacent to each other in a circumferential direction in the radial direction.

7. The rotating electric machine according to claim 1, characterized in that:

the rotor core has a protrusion that protrudes radially outward from a surface of the rotor core to between 2 permanent magnets adjacent to each other in the circumferential direction.

8. The rotating electric machine according to claim 7, characterized in that:

the outer end of the protrusion is located inward of the outer end of the permanent magnet in the radial direction.

9. The rotating electric machine according to claim 7, characterized in that:

the rotor core has a plurality of the projections arranged in the axial direction.

10. The rotating electric machine according to claim 7, characterized in that:

the projection is formed by a screw provided to the rotor core.

11. A traction machine system for an elevator, comprising:

a traction machine having a sheave; and

a rotating motor connected with the rope wheel,

the rotating electrical machine according to any one of claims 1 to 10.