CN111371215A

CN111371215A - High-speed permanent magnet motor rotor structure, motor and compressor

Info

Publication number: CN111371215A
Application number: CN201811593286.3A
Authority: CN
Inventors: 刘华; 张治平; 叶文腾; 李宏波; 钟瑞兴; 陈玉辉; 亓静利
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2018-12-25
Filing date: 2018-12-25
Publication date: 2020-07-03

Abstract

The invention relates to a motor rotor, a motor and a compressor, wherein the motor rotor (10) comprises: a first shaft (1); a second shaft (2); a permanent magnet (3) disposed between the first shaft (1) and the second shaft (2); the sheath (4) is sleeved on the peripheries of the first shaft (1), the permanent magnet (3) and the second shaft (2) and is used for connecting the first shaft (1), the permanent magnet (3) and the second shaft (2); and the limiting structure is used for limiting the sheath (4) to move along the axial direction and consists of a limiting boss (5), and the limiting boss (5) is arranged on the first shaft (1) or the second shaft (2). The motor includes a motor rotor. The compressor includes a motor. The invention can improve the structural strength of the motor rotor and ensure the safe and reliable operation of the motor rotor at high rotating speed.

Description

High-speed permanent magnet motor rotor structure, motor and compressor

Technical Field

The invention relates to the technical field of compressors, in particular to a high-speed permanent magnet motor rotor structure, a motor and a compressor.

Background

Centrifugal refrigeration compressors belong to the high speed type of compressors, the compressor rotor rotates at high speed during operation, and reliable bearings are required to support the rotor. The bearings used by the conventional rotor mainly comprise a rolling bearing, an oil film bearing and a magnetic suspension bearing. For rolling bearings and oil film bearings, the compressor needs an additional oil lubrication system and a complicated oil supply path system, and at the same time, since the refrigerant and the lubricating oil have compatibility, a separation system needs to be added in the system, which results in an excessively complicated and large whole system.

The rolling bearing and the sliding bearing are not suitable for a high-speed compressor due to large friction. The air suspension bearing is adopted as the bearing of the high-speed compressor, so that the friction loss of the bearing can be reduced, the temperature of the bearing is reduced, and the reliability of the compressor is improved. Therefore, the air suspension centrifugal compressor is an important technical approach for solving the problems of high speed and miniaturization of the centrifugal compressor.

In the air suspension centrifugal compressor, compared with a fixed-frequency motor, the high-speed permanent magnet motor can greatly improve the energy efficiency of the centrifugal compressor, however, the structural strength of the motor of the centrifugal compressor is one of the design difficulties of the motor at high rotating speed. The lower the structural strength of each part on the rotor, the poorer the structural safety of the motor.

It is noted that the information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information constitutes prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide a motor rotor, a motor and a compressor, which can meet the electromagnetic high-efficiency design, ensure the structural strength of a permanent magnet and improve the safety of the motor.

To achieve the above object, the present invention provides a rotor of an electric motor, comprising:

a first shaft;

a second shaft;

a permanent magnet disposed between the first shaft and the second shaft;

the sheath is sleeved on the peripheries of the first shaft, the permanent magnet and the second shaft and is used for connecting the first shaft, the permanent magnet and the second shaft; and

and the limiting structure is used for limiting the sheath to move along the axial direction and consists of a limiting boss, and the limiting boss is arranged on the first shaft or the second shaft.

Optionally, the permanent magnet is a solid cylinder.

Optionally, the sheath and the first shaft, the permanent magnet and the second shaft are in interference fit.

Optionally, the limiting boss is arranged on the first shaft and is integrally formed with the first shaft; or the limiting boss is arranged on the second shaft and is integrally formed with the second shaft.

Optionally, the first shaft comprises a first shaft section close to the permanent magnet, the second shaft comprises a second shaft section close to the permanent magnet, and the diameter of the first shaft section and the diameter of the second shaft section are both the same as the diameter of the permanent magnet.

Optionally, the length of the permanent magnet is greater than the length of the first shaft segment and the length of the second shaft segment.

Optionally, the length of the first shaft segment and the length of the second shaft segment are equal.

Optionally, the first shaft and/or the second shaft are provided with lightening holes.

Optionally, the lightening holes are provided inside the first shaft and/or the second shaft; or the lightening holes are blind holes and extend from the end face close to the permanent magnet to the direction far away from the permanent magnet; or the lightening holes are blind holes and extend from the end face far away from the permanent magnet to the direction close to the permanent magnet; or the lightening holes are through holes.

Optionally, the first shaft and/or the second shaft is provided with a vent hole.

Optionally, the first shaft and/or the second shaft is provided with a cooling hole, and a cooling medium for cooling the first shaft and/or the second shaft is introduced into the cooling hole.

Optionally, the cooling holes are arranged obliquely with respect to the axis of the first shaft or the second shaft.

Optionally, a cooling hole is provided on the first shaft, the cooling hole being a through hole and extending from a circumferential side surface of the first shaft to an end surface of the first shaft near the permanent magnet, obliquely with respect to an axis of the first shaft; and/or the cooling hole is arranged on the second shaft, is a through hole and extends from the circumferential side surface of the second shaft to the end surface of the second shaft close to the permanent magnet in an inclined way relative to the axis of the second shaft.

Optionally, the cooling holes extend in a radial direction, and the first shaft and/or the second shaft are provided with cooling channels extending in an axial direction, and the cooling holes are communicated with the cooling channels.

In order to achieve the purpose, the invention further provides a motor which comprises the motor rotor.

In order to achieve the purpose, the invention further provides a compressor which comprises the motor.

Optionally, the compressor further comprises a gas bearing on which the motor rotor is supported.

Based on the technical scheme, the motor rotor embodiment of the invention adopts the sheath to connect the first shaft, the permanent magnet and the second shaft, so that the permanent magnet can be effectively protected, the reliable connection of all components can be realized, and the overall structural strength of the motor rotor can be improved; compared with the technical scheme that the limiting bosses are respectively arranged on the two sides of the sheath, the motor rotor limiting structure can enable the first shaft, the permanent magnet and the second shaft to be in close contact with each other, avoids gaps among the first shaft, the permanent magnet and the second shaft due to manufacturing errors or assembly errors and the like, and reduces the structural strength of the motor rotor.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a schematic structural diagram of an embodiment of a rotor of an electric machine according to the present invention.

Fig. 2 is a schematic view of an arrangement of lightening holes in an embodiment of a rotor of an electric machine according to the present invention.

Fig. 3 is a schematic view of another arrangement of lightening holes in one embodiment of the rotor of the motor according to the invention.

Fig. 4 is a schematic view of another arrangement of lightening holes in an embodiment of a rotor of an electric machine according to the present invention.

Fig. 5 is a schematic view of an arrangement of cooling holes in an embodiment of a rotor of an electric machine according to the invention.

Fig. 6 is a schematic view of another arrangement of cooling holes in an embodiment of a rotor of an electric machine according to the invention.

Fig. 7 is a schematic view showing an internal structure of one embodiment of the compressor of the present invention.

In the figure:

1. a first shaft; 2. a second shaft; 3. a permanent magnet; 4. a sheath; 5. a limiting boss; 6. lightening holes; 7. an exhaust hole; 8. a cooling hole; 9. a cooling channel;

10. a motor rotor; 20. a motor stator; 30. a first gas bearing; 40. a motor housing; 50. a second gas bearing; 60. a first housing; 70. a bearing seat; 80. a second housing; 90. an impeller; 100. a connecting member.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "central," "lateral," "longitudinal," "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and for simplicity in description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the scope of the invention.

As shown in fig. 1, in an embodiment of the motor rotor provided by the present invention, the motor rotor includes a first shaft 1, a second shaft 2, a permanent magnet 3 and a sheath 4, the permanent magnet 3 is disposed between the first shaft 1 and the second shaft 2, the sheath 4 is sleeved on the peripheries of the first shaft 1, the permanent magnet 3 and the second shaft 2, and the sheath 4 is used for connecting the first shaft 1, the permanent magnet 3 and the second shaft 2.

In the embodiment, the first shaft 1, the permanent magnet 3 and the second shaft 2 are connected by the sheath 4, so that the permanent magnet 3 can be effectively protected, the reliable connection of all components is realized, and the overall structural strength of the motor rotor is effectively improved.

The motor rotor further comprises a limiting structure, the limiting structure is used for limiting the sheath 4 to move along the axial direction, the limiting structure is composed of a limiting boss 5, and the limiting boss 5 is arranged on the first shaft 1 or the second shaft 2.

Limiting structure comprises a spacing boss, and the benefit that sets up like this is compared in the technical scheme who sets up a spacing boss respectively in the both sides of sheath, can make intimate contact each other between primary shaft, permanent magnet and the secondary shaft, avoids having the clearance because reasons such as manufacturing error or assembly error cause between primary shaft, permanent magnet and the secondary shaft, reduces electric motor rotor's structural strength.

The permanent magnet 3 is a solid cylinder, so that the electromagnetic strength of the motor rotor can be increased, the volume of the permanent magnet is reduced, and the miniaturization of the compressor is facilitated; and meanwhile, the linear velocity of the outer surface of the permanent magnet is reduced, the centrifugal force borne by the permanent magnet and the sheath is reduced, and the overall structural strength of the motor rotor is enhanced.

The jacket 4 may be an interference fit with the first shaft 1, the permanent magnet 3 and the second shaft 2. Therefore, the jacket 4 can be tightly combined with the first shaft 1, the permanent magnet 3 and the second shaft 2 in the running process of the motor rotor, relative movement cannot occur, the connection strength between the jacket 4 and the first shaft 1, between the permanent magnet 3 and the second shaft 2 is enhanced, and the structural stability of the motor rotor in high-speed rotation is ensured.

The limit boss 5 may be provided on the first shaft 1 and integrally formed with the first shaft 1. The limiting boss 5 can also be arranged on the second shaft 2 and is integrally formed with the second shaft 2.

The first shaft 1 comprises a first shaft section close to the permanent magnet 3, the second shaft 2 comprises a second shaft section close to the permanent magnet 3, and the diameter of the first shaft section and the diameter of the second shaft section are both the same as the diameter of the permanent magnet 3. The arrangement is convenient for realizing interference fit among the sheath 4, the first shaft 1, the permanent magnet 3 and the second shaft 2.

The length of the permanent magnet 3 is larger than that of the first shaft section and that of the second shaft section, so that the length of the permanent magnet 3 is increased as much as possible, and the electromagnetic strength is increased.

The length of the first shaft section is equal to that of the second shaft section, so that the motor rotor is uniformly stressed.

As shown in fig. 2, the first shaft 1 and/or the second shaft 2 are provided with lightening holes 6. By arranging the lightening holes 6, the overall weight of the motor rotor can be reduced.

The number of the lightening holes 6 can be flexibly set according to actual requirements. Alternatively, the number of lightening holes 6 provided on the first shaft 1 and the number of lightening holes 6 provided in the second shaft 2 are the same and are symmetrically arranged with respect to the permanent magnet 3.

The arrangement of the lightening holes 6 can be selected in many ways. For example, in one embodiment, the lightening holes 6 are arranged inside the first shaft 1 and/or the second shaft 2, i.e. the lightening holes 6 are closed in the circumferential direction. In another embodiment, as shown in fig. 2, the lightening holes 6 are blind holes and extend from the end surface close to the permanent magnet 3 to the direction away from the permanent magnet 3. In yet another embodiment, as shown in fig. 3, the lightening holes 6 are blind holes and extend from the end surface away from the permanent magnet 3 to the direction close to the permanent magnet 3. In yet another embodiment, as shown in fig. 4, the lightening holes 6 are through holes.

The first shaft 1 and/or the second shaft 2 may also be provided with a vent hole 7. Through setting up exhaust hole 7, can prevent to appear the unable close in clearance owing to sneaking into gas between the first axle 1 and the permanent magnet 3 and between permanent magnet 3 and the second axle 2 when electric motor rotor assembles, reduce electric motor rotor's overall structure intensity. The exhaust holes 7 can also play a weight-reducing role.

The exhaust holes 7 can be independently arranged, so that the end surfaces of the first shaft 1 and/or the second shaft 2 close to the permanent magnet 3 are communicated with the external environment, and the exhaust effect is realized.

The exhaust holes 7 may also be arranged in cooperation with the lightening holes 6, as shown in fig. 3, the lightening holes 6 extending from the end surface far away from the permanent magnet 3 to the direction close to the permanent magnet 3 are arranged on the first shaft 1 and the second shaft 2, the exhaust holes 7 are communicated with the lightening holes 6, and the exhaust holes 7 extend to the end surfaces of the first shaft 1 and the second shaft 2 close to the permanent magnet 3.

The first shaft 1 and/or the second shaft 2 are/is provided with cooling holes 8, and cooling media for cooling the first shaft 1 and/or the second shaft 2 are introduced into the cooling holes 8. Through setting up cooling hole 8, can cool off electric motor rotor, prevent that electric motor rotor from high temperature in the course of the work, effectively protect electric motor rotor.

As shown in fig. 5, the cooling hole 8 is disposed obliquely with respect to the axis of the first shaft 1 or the second shaft 2.

Cooling holes 8 are provided on the first shaft 1, and the cooling holes 8 are through holes and extend from the circumferential side surface of the first shaft 1 to the end surface of the first shaft 1 near the permanent magnets 3 obliquely with respect to the axis of the first shaft 1. The cooling hole 8 may be provided in the second shaft 2, and the cooling hole 8 is a through hole and extends from a circumferential side surface of the second shaft 2 to an end surface of the second shaft 2 near the permanent magnet 3 obliquely with respect to the axis of the second shaft 2.

The advantage of this arrangement is that the cooling medium from the circumferential side of the motor rotor can be intensively led to the permanent magnets 3, and efficient cooling of the permanent magnets 3 is achieved.

As shown in fig. 6, the cooling holes 8 extend in the radial direction, and the first shaft 1 and/or the second shaft 2 are provided with cooling passages 9 extending in the axial direction, and the cooling holes 8 communicate with the cooling passages 9.

The cooling channel 9 on the first shaft 1 penetrates through the first shaft 1 along the axial direction, the cooling holes 8 penetrate through the first shaft 1 along the radial direction, the number of the cooling holes 8 is multiple in the axial direction of the first shaft 1, and the multiple cooling holes 8 are also arranged at different positions of the first shaft 1 in the circumferential direction. The cooling channel 9 on the second shaft 2 penetrates through the second shaft 2 along the axial direction, the cooling holes 8 penetrate through the second shaft 2 along the radial direction, the number of the cooling holes 8 is multiple in the axial direction of the second shaft 2, and the multiple cooling holes 8 are also arranged at different positions of the second shaft 2 in the circumferential direction.

In other embodiments of the motor rotor provided by the invention, the lightening holes 6, the exhaust holes 7, the cooling holes 8 and the cooling channels 9 can be freely combined, and the exhaust holes 7, the cooling holes 8 and the cooling channels 9 can be used as a form of the lightening holes 6 and can also play a role in lightening.

Through the description of the multiple embodiments of the motor rotor, the motor rotor of the invention adopts the solid permanent magnet, so that the electromagnetic strength can be increased, and the size of the motor rotor can be effectively reduced on the premise of reaching the same electromagnetic strength; the limiting structure consisting of the limiting boss is arranged, so that axial limiting can be realized, and gaps between the first shaft and the permanent magnet and between the permanent magnet and the second shaft due to manufacturing errors can be avoided; the first shaft, the permanent magnet and the second shaft are connected through the sheath, so that the permanent magnet can be effectively protected, the structural strength of the motor rotor is improved, and the motor rotor is ensured to run safely and reliably at a high rotating speed; and a lightening hole, an exhaust hole and a cooling hole are also arranged, so that the comprehensive performance of the motor rotor is further improved.

Based on the motor rotor, the invention further provides a motor which comprises the motor rotor.

The invention also provides a compressor. The compressor comprises the motor.

The compressor further includes a gas bearing on which the motor rotor is supported.

As shown in fig. 7, the gas bearing includes a first gas bearing 30 and a second gas bearing 50, the first gas bearing 30 being arranged in a radial direction to support the motor rotor 10; the second gas bearing 50 is arranged in the axial direction to axially position the motor rotor 10.

The motor also includes a motor stator 20 and a motor housing 40. The compressor further comprises a first housing 60, a bearing seat 70, a second housing 80, an impeller 90 and a connecting piece 100, wherein the first housing 60 and the second housing 80 are fixedly connected with the motor housing 40. The first gas bearing 30 and the second gas bearing 50 are both mounted on a bearing housing 70. The two-stage impellers 90 are connected to both ends of the motor rotor 10 by connection members 100, respectively. The two stages of impellers 90 are arranged back-to-back to facilitate reduction of axial forces during operation of the compressor. The two first gas bearings 30 which are radially arranged are respectively arranged at two ends of the motor rotor 10 and are simultaneously positioned between the two impellers 90, so that the bearing stress is uniform, the rigidity of the motor rotor 10 is uniform, and the problem of large vibration caused by overlong cantilevers of the motor rotor 10 is solved. The second gas bearing 50 arranged axially is located outside the first-stage impeller 90, so that the motor rotor 10 can operate stably in the axial direction.

The positive technical effects of the motor rotor in the above embodiments are also applicable to the motor and the compressor, and are not described herein again.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims

1. An electric machine rotor (10), characterized by comprising:

a first shaft (1);

a second shaft (2);

a permanent magnet (3) arranged between the first shaft (1) and the second shaft (2);

the sheath (4) is sleeved on the peripheries of the first shaft (1), the permanent magnet (3) and the second shaft (2) and is used for connecting the first shaft (1), the permanent magnet (3) and the second shaft (2); and

the limiting structure is used for limiting the sheath (4) to move along the axial direction and consists of a limiting boss (5), and the limiting boss (5) is arranged on the first shaft (1) or the second shaft (2).

2. An electric machine rotor (10) according to claim 1, characterized in that the permanent magnets (3) are solid cylinders.

3. The electric machine rotor (10) according to claim 1, characterized in that the sheath (4) is an interference fit with the first shaft (1), the permanent magnets (3) and the second shaft (2).

4. The electric machine rotor (10) according to claim 1, characterized in that the limit boss (5) is provided on the first shaft (1) and is integrally formed with the first shaft (1); or the limiting boss (5) is arranged on the second shaft (2) and is integrally formed with the second shaft (2).

5. The electric machine rotor (10) according to claim 1, characterized in that the first shaft (1) comprises a first shaft section adjacent to the permanent magnet (3) and the second shaft (2) comprises a second shaft section adjacent to the permanent magnet (3), the diameter of the first shaft section and the diameter of the second shaft section being the same as the diameter of the permanent magnet (3).

6. An electric machine rotor (10) according to claim 5, characterized in that the length of the permanent magnets (3) is larger than the length of the first shaft section and the length of the second shaft section.

7. The electric machine rotor (10) of claim 5, wherein the length of the first shaft segment and the length of the second shaft segment are equal.

8. The electric machine rotor (10) according to claim 1, characterized in that the first shaft (1) and/or the second shaft (2) are provided with lightening holes (6).

9. The electric machine rotor (10) according to claim 8, characterized in that the lightening holes (6) are provided inside the first shaft (1) and/or the second shaft (2); or the lightening holes (6) are blind holes and extend from the end face close to the permanent magnet (3) to the direction far away from the permanent magnet (3); or the lightening holes (6) are blind holes and extend from the end face far away from the permanent magnet (3) to the direction close to the permanent magnet (3); or the lightening holes (6) are through holes.

10. The electric machine rotor (10) according to claim 1, characterized in that the first shaft (1) and/or the second shaft (2) is provided with exhaust holes (7).

11. The electric machine rotor (10) according to claim 1, characterized in that the first shaft (1) and/or the second shaft (2) are provided with cooling holes (8), and a cooling medium for cooling the first shaft (1) and/or the second shaft (2) is introduced into the cooling holes (8).

12. The electric machine rotor (10) according to claim 11, characterized in that the cooling holes (8) are arranged obliquely with respect to the axis of the first shaft (1) or the second shaft (2).

13. The electric machine rotor (10) according to claim 12, characterized in that the cooling hole (8) is provided on the first shaft (1), the cooling hole (8) being a through hole and extending from a circumferential side surface of the first shaft (1) obliquely with respect to an axis of the first shaft (1) to an end surface of the first shaft (1) near the permanent magnet (3); and/or the cooling hole (8) is arranged on the second shaft (2), the cooling hole (8) is a through hole and extends from the circumferential side surface of the second shaft (2) to the end surface of the second shaft (2) close to the permanent magnet (3) in an inclined manner relative to the axis of the second shaft (2).

14. The electric machine rotor (10) according to claim 11, characterized in that the cooling holes (8) extend in a radial direction and that the first shaft (1) and/or the second shaft (2) are provided with cooling channels (9) extending in an axial direction, the cooling holes (8) communicating with the cooling channels (9).

15. An electric machine, characterized in that it comprises an electric machine rotor (10) according to any one of claims 1 to 14.

16. A compressor, comprising the motor of claim 15.

17. Compressor according to claim 16, characterized by further comprising a gas bearing on which the motor rotor (10) is supported.