WO2020073549A1

WO2020073549A1 - Motor rotor, motor, and air conditioner

Info

Publication number: WO2020073549A1
Application number: PCT/CN2019/070663
Authority: WO
Inventors: 贾金信; 张小波; 刘建宁; 张芳; 李广海; 魏琼; 闫瑾; 梁建东
Original assignee: 珠海格力电器股份有限公司
Priority date: 2018-10-08
Filing date: 2019-01-07
Publication date: 2020-04-16
Also published as: CN109245361A

Abstract

A motor rotor, a motor, and an air conditioner. The motor rotor comprises a permanent magnet (1), a copper shielding layer (2), and a protective layer (3). The copper shielding layer (2) is sleeved outside the permanent magnet (1); the protective layer (3) is sleeved outside the copper shielding layer (2); the copper shielding layer (2) is of a segmental structure. According to the motor rotor, the loss of the shielding layer can be reduced while transfer of heat of the permanent magnet is implemented.

Description

Motor rotor, motor and air conditioner

This application requires the priority of the Chinese patent application filed on October 08, 2018 in the Chinese Patent Office with the application number 201811168365.X and the invention titled "Motor Rotor, Motor and Air Conditioner", the entire contents of which are incorporated by reference in this document Applying.

Technical field

This application belongs to the technical field of motors, and specifically relates to a motor rotor, a motor and an air conditioner.

Background technique

High-speed permanent magnet synchronous motor has many advantages such as high power density, good dynamic response and simple structure, and has become one of the research hotspots in the field of international electrical engineering. However, the permanent magnets in the rotor generally use sintered NdFeB permanent magnet material, because this permanent magnet material is not compressive or tensile. In order to ensure that the permanent magnet has sufficient strength at high speed, a layer of high-strength rotor sheath is generally wrapped around the permanent magnet. The rotor sheath and the permanent magnet adopt an interference fit to ensure that the permanent magnet still bears certain compressive stress during operation. So as to ensure the safe operation of high-speed motors.

At present, there are two kinds of commonly used sheaths, one is a non-magnetic high-strength metal sheath, and the other is a carbon fiber binding type sheath. Carbon fiber-reinforced composite materials have low conductivity, which solves the problem of eddy current loss in the use of metal sheaths, but it cannot shield the harmonic magnetic field entering the permanent magnet, so a large amount of eddy current loss will still occur in the permanent magnet. At the same time, carbon fiber is a poor conductor of heat, which leads to poor heat dissipation of the permanent magnet rotor, and the carbon fiber sheath is complicated in process and high in cost. Therefore, in industrial applications, a non-magnetic metal sheath is widely used. However, the metal sheath is a conductive material. Under the action of high-frequency electromagnetic fields, eddy current loss will occur, which will cause the sheath to heat up. Since the sheath is in close contact with the rotor permanent magnet, the heat in the sheath is easily transferred to the permanent magnet. In addition, the general alloy sheath material has low conductivity and limited shielding effect on harmonic magnetic fields, resulting in large eddy current losses in permanent magnets. The above factors will lead to irreversible demagnetization when the temperature rise of the permanent magnet is too high, which will degrade the performance of the motor or even damage it. Therefore, no matter what kind of protection scheme is adopted, there is an urgent need for a method or structure to reduce the temperature rise of the rotor permanent magnet.

At present, the use of high-conductivity copper shields to reduce high-speed rotor losses has become the most popular shielding measure. But the current patents do not mention how to reduce the eddy current loss of the copper shield itself.

The rotor structure of the high-speed permanent magnet motor of the related art is a surface-mounted rotor structure. The most obvious feature of this structure is that a thin copper shield layer is added between the protective layer and the outer surface of the permanent magnet. The benefits of doing so It is possible to transfer a large amount of eddy current loss that should be generated on the surface of the permanent magnet to the metal shield layer itself, which can greatly reduce the problem of excessive local temperature of the permanent magnet. These patented structures all have a large defect, namely If the heat of the copper shielding layer is too high, it will still be transferred to the magnetic steel. Therefore, a new structure is needed to achieve the heat transfer of the magnetic steel and reduce the loss of the shielding layer itself.

Summary of the invention

Therefore, the technical problem to be solved by the present application is to provide a motor rotor, a motor, and an air conditioner, which can reduce the loss of the shield layer itself while realizing the heat transfer of the permanent magnet.

In order to solve the above problems, the present application provides a motor rotor, which includes a permanent magnet, a copper shielding layer and a protective layer. The copper shielding layer is sheathed outside the permanent magnet, the protective layer is sheathed outside the copper shielding layer式结构。 Style structure.

Optionally, the copper shielding layer adopts an axial segmented structure, multiple copper shielding layers are arranged at intervals along the axial direction of the permanent magnet, and a filling layer is provided between adjacent copper shielding layers.

Optionally, the copper shielding layer adopts a circumferential segmented structure, multiple sections of copper shielding layers are spaced along the circumferential direction of the permanent magnet, and a filling layer is provided between adjacent copper shielding layers.

Optionally, the number of segments of the copper shielding layer is n, where n> 2.

Optionally, there is a gap fit, a transition fit, or an interference fit between the copper shield layer and the permanent magnet.

Optionally, the radial thickness of the copper shielding layer is h, where 0.03 mm ﹤ h ﹤ 1.5 mm.

Optionally, the gap between the segments of the copper shielding layer is δ, where 0 ﹤ δ ﹤ 1mm.

Optionally, the filling layer is epoxy resin.

Optionally, the protective layer is made of alloy material or non-metal composite material.

Optionally, the rotor of the motor further includes a rotating shaft, and the permanent magnet is sleeved outside the rotating shaft and is glued and fixed to the rotating shaft.

According to another aspect of the present application, there is provided a motor including a motor rotor, the motor rotor being the above-mentioned motor rotor.

According to still another aspect of the present application, there is provided an air conditioner including a motor rotor, the motor rotor being the above-mentioned motor rotor.

The motor rotor provided by the present application includes a permanent magnet, a copper shielding layer and a protective layer. The copper shielding layer is sheathed outside the permanent magnet, and the protective layer is sheathed outside the copper shielding layer. The copper shielding layer adopts a segmented structure. Because the copper shielding layer adopts a segmented structure, it not only largely shields the electromagnetic harmonics entering the permanent magnet, reduces the eddy current loss on the surface of the permanent magnet, but also reduces the shielding layer while achieving the heat transfer of the permanent magnet. Own loss.

BRIEF DESCRIPTION

1 is a schematic diagram of a longitudinal cross-sectional structure of a motor rotor according to a first embodiment of this application;

2 is a schematic diagram of a cross-sectional structure of a motor rotor according to a second embodiment of the present application.

The reference signs are expressed as:

1. Permanent magnet; 2. Copper shielding layer; 3. Protective layer; 4. Filling layer; 5. Rotating shaft.

detailed description

Referring to FIG. 1 and FIG. 2 together, according to an embodiment of the present application, the motor rotor includes a permanent magnet 1, a copper shielding layer 2 and a protective layer 3, the copper shielding layer 2 is sheathed outside the permanent magnet 1, and the protective layer 3 is sheathed Outside the copper shielding layer 2, the copper shielding layer 2 adopts a segmented structure.

Because the copper shielding layer adopts a segmented structure, it not only largely shields the electromagnetic harmonics entering the permanent magnet, reduces the eddy current loss on the surface of the permanent magnet, but also reduces the shielding layer while achieving heat transfer of the permanent magnet Own loss.

In the first embodiment of the present application, the copper shielding layer 2 adopts an axially segmented structure, the multi-segment copper shielding layer 2 is spaced along the axial direction of the permanent magnet 1, and the adjacent copper shielding layer 2 is provided with a filling Layer 4. The filling layer is made of insulating material, so it can reduce the contact stress between the gap between the copper shield layer 2 of the adjacent section and the protective layer 3, and at the same time play the role of blocking the eddy current circuit between different shield layers, reducing the surface of the permanent magnet The eddy current loss also reduces the loss of the shielding layer itself.

Optionally, the filling layer 4 is epoxy resin, which can reduce the contact stress with the protective layer 3 at the same time, and at the same time play a role of blocking the eddy current circuit between different copper shielding layers.

In the second embodiment of the present application, the copper shielding layer 2 adopts a circumferential segmented structure, multiple sections of the copper shielding layer 2 are spaced along the circumferential direction of the permanent magnet 1, and a filling is provided between adjacent copper shielding layers 2 Layer 4.

Whether the axial segmented structure or the circumferential segmented structure is adopted, it can have a significant effect in reducing the eddy current loss of the permanent magnet 1 and the copper shield layer 2 itself. It is also possible to use a combination of circumferential segment and axial segment copper shield layers at the same time, so that the circumferential segment and axial segment are used in combination, thereby playing the role of blocking the eddy current circuit between different shield layers, reducing the permanent The effect of eddy current loss on the surface of the magnet.

Optionally, the number of segments of the copper shielding layer 2 is n, where n> 2, so that the copper shielding layer 2 can have a sufficient number of segments to play a more effective role in blocking the eddy current circuit between different shielding layers .

The radial thickness of the copper shielding layer 2 is h, of which 0.03mm ﹤ h ﹤ 1.5mm. The thickness of the shielding layer is within a certain range. As the thickness increases, the loss reduction effect is more obvious, but the thickness is too small (such as less than 0.03mm), resulting in a sharp increase in the eddy current density in the shielding layer. When the thickness is too large, (such as (When it is greater than 1.5mm), the improvement effect will not increase, but occupy the space of the high-strength protective sleeve. Therefore, in order to prevent excessive eddy current loss induced in the shielding layer and affect its effect of reducing the rotor eddy current loss, it will not affect the protection The thickness of the cover and the thickness of the shielding layer should ensure a certain suitable size. For different size shafts, the shielding layer has a better thickness value.

The gap between the segments of the copper shielding layer 2 is δ, where 0 ﹤ δ ﹤ 1mm. The gap δ is mainly the process gap during processing. The gap filled with epoxy resin is mainly to reduce the stress concentration problem of the carbon fiber and other protective sleeves at the gap.

A gap fit, a transition fit, or an interference fit may be used between the copper shielding layer 2 and the permanent magnet 1, so that the copper shielding layer 2 and the permanent magnet 1 form a good matching relationship.

The protective layer 3 is made of alloy material or non-metal composite material. The protective layer 3 has an interference effect on the surface of the copper shielding layer 2 and exerts a pressing force on the permanent magnet 1 to protect the permanent magnet 1 from damage due to centrifugal force during high-speed rotation. The non-metallic composite material is, for example, carbon fiber.

The rotor of the motor also includes a rotating shaft 5, and the permanent magnet 1 is sleeved outside the rotating shaft 5 and is glued and fixed to the rotating shaft 5.

In this embodiment, the permanent magnet is a magnetic steel, which is made of neodymium iron boron or samarium cobalt. The magnetic steel is a ring structure, and its inner surface is bonded to the rotating shaft 5 by a special magnetic steel glue.

When assembling the rotor of the motor, first attach the ring magnet to the motor shaft 5 through a special magnet adhesive to confirm that it will not loosen; then assemble the radially segmented copper shield 2 to the magnet in turn On the surface, epoxy resin is applied at the section gap to fill the gap; finally, a protective layer 3 is installed outside the copper shield layer 2 by interference.

According to an embodiment of the present application, the motor includes a motor rotor, which is the above-mentioned motor rotor.

According to an embodiment of the present application, the air conditioner includes a motor rotor, which is the aforementioned motor rotor.

It is easily understood by those skilled in the art that the above-mentioned advantageous methods can be freely combined and superimposed on the premise of no conflict.

The above are only the preferred embodiments of this application and are not intended to limit this application. Any modification, equivalent replacement and improvement made within the spirit and principle of this application should be included in the scope of protection of this application Inside. The above are only the preferred embodiments of the present application. It should be pointed out that those of ordinary skill in the art can make several improvements and modifications without departing from the technical principles of the present application. These improvements and modifications should also be made It is regarded as the scope of protection of this application.

Claims

A motor rotor includes a permanent magnet (1), a copper shielding layer (2) and a protective layer (3), the copper shielding layer (2) is sleeved outside the permanent magnet (1), and the protective layer ( 3) The copper shielding layer (2) is sheathed outside, and the copper shielding layer (2) adopts a segmented structure.
The motor rotor according to claim 1, wherein the copper shielding layer (2) adopts an axial segmented structure, and multiple sections of the copper shielding layer (2) are spaced along the axial direction of the permanent magnet (1) A filling layer (4) is provided between adjacent copper shielding layers (2).
The motor rotor according to claim 1, wherein the copper shielding layer (2) adopts a circumferential segmented structure, and a plurality of segments of the copper shielding layer (2) are spaced along the circumferential direction of the permanent magnet (1) A filling layer (4) is provided between adjacent copper shielding layers (2).
The motor rotor according to claim 2, wherein the copper shielding layer (2) adopts a circumferentially segmented structure, and a plurality of sections of the copper shielding layer (2) are spaced along the circumferential direction of the permanent magnet (1) A filling layer (4) is provided between adjacent copper shielding layers (2).
The motor rotor according to any one of claims 2 to 4, wherein the number of segments of the copper shield layer (2) is n, where n> 2.
The motor rotor according to claim 1, wherein the copper shield layer (2) and the permanent magnet (1) are a gap fit, a transition fit, or an interference fit.
The motor rotor according to claim 1, wherein the radial thickness of the copper shield layer (2) is h, where 0.03 mm ﹤ h ﹤ 1.5 mm.
The motor rotor according to claim 1, wherein the gap between the segments of the copper shielding layer (2) is δ, wherein 0 ﹤ δ ﹤ 1mm.
The motor rotor according to any one of claims 2 to 4, wherein the filling layer (4) is epoxy resin.
The motor rotor according to claim 1, wherein the protective layer (3) is made of alloy material or non-metal composite material.
The motor rotor according to any one of claims 1 to 4, wherein the motor rotor further includes a rotating shaft (5), and the permanent magnet (1) is sleeved outside the rotating shaft (5) and The rotating shaft (5) is glued and fixed.
A motor includes a motor rotor, and the motor rotor is the motor rotor according to any one of claims 1 to 11.
An air conditioner includes a motor rotor, and the motor rotor is the motor rotor according to any one of claims 1 to 11.