WO2021093102A1

WO2021093102A1 - Permanent magnet fixing structure

Info

Publication number: WO2021093102A1
Application number: PCT/CN2019/127889
Authority: WO
Inventors: 朱利湘; 王冬梅; 李广; 晏才松; 刘勇; 崔斯柳; 王国辉; 曹晴
Original assignee: 中车株洲电机有限公司
Priority date: 2019-11-12
Filing date: 2019-12-24
Publication date: 2021-05-20
Also published as: CN110798000B; CN110798000A

Abstract

A permanent magnet fixing structure. A permanent magnet is mounted at an inner surface or an outer surface of a rotor core by two adjacent magnetic isolating pressing bars, the magnetic isolating pressing bars and the permanent magnet having a clearance fit. The magnetic isolating pressing bars comprise a fixed section fitted in the rotor iron core and a pressing section that presses against the permanent magnet tightly. The fixed section is inserted into an interior of the rotor core, and the two are fixed by a securing member disposed at a top end of the fixed section after assembly. A cross section of the pressing section has a swallowtail shape. A side surface of the permanent magnet abutting the pressing section has a shape matching that of the pressing section. The pressing section in the structure ensures that the permanent magnet does not fall off the inner surface or the outer surface of the rotor core. In addition, the securing member fixes the fixed section to the rotor core. In this way, the permanent magnet fixing structure has a simple process, and is reliable during use.

Description

Permanent magnet fixing structure

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on November 12, 2019, the application number is 201911102038.9, and the application name is "a permanent magnet fixing structure", the entire content of which is incorporated into this application by reference.

Technical field

This application belongs to the technical field of permanent magnet direct drive motors, and specifically relates to a permanent magnet fixing structure.

Background technique

Permanent magnets are the source of magnetic force that generates the magnetic field. The permanent magnets in the permanent magnet synchronous motor are all installed on the rotor to generate the rotor magnetic field. The rotor magnetic field interacts with the stator magnetic field to transform electrical energy into mechanical energy or mechanical energy into electrical energy. According to the position of the permanent magnet on the rotor, the rotor structure of the permanent magnet synchronous motor is generally divided into three types: surface type, built-in type and claw pole type. Surface permanent magnets are permanent magnets installed on the surface of the rotor, including the inner and outer surfaces of the rotor.

In the traditional surface permanent magnet structure, the permanent magnet is usually fixed to the surface of the rotor core with glue only. The disadvantage of this method is that the glue is easy to fail and age under the condition of large vibration and heat. This causes the permanent magnet to shift or even fall off in the circumferential direction.

In the prior art, the above-mentioned fixing methods of the permanent magnets have been improved, and it is common to fix the permanent magnets on the inner surface or outer surface of the rotor core by means of a magnetic isolation bar. Magnetic barrier strips are usually installed between adjacent permanent magnets to compress or fix permanent magnets. They are made of non-magnetic materials to prevent adjacent permanent magnets with different polarities from causing large magnetic flux leakage here. In this way, the magnetic barrier strip itself is fixed on the surface of the rotor core in two ways:

One is to fix it by bolts or screws. This method requires bolts or screws with specifications above M6 (because only bolts or screws above M6 can have a certain tightening force) to fasten the magnetic barrier strips, but the width of the magnetic barrier strips is less than In the case of 6mm, this method cannot be used.

One is clamping. For example, the first dovetail groove is arranged on the inner surface of the rotor core in the axial direction. The cross section of the magnetic isolation bead is in the shape of a double dovetail. The first dovetail of the magnetic isolation bead is clamped into the first dovetail groove in the rotor core. The second dovetail adjacent to the magnetic bead forms another dovetail groove, and the permanent magnet is clamped into the dovetail groove. However, this structural design has contradictions between assembly process requirements and operational reliability requirements: from the perspective of assembly process, in order to facilitate the insertion and installation of the magnetic barrier strip and the insertion and installation of the permanent magnet, the dimensions between these parts are required to adopt a clearance fit; However, when used under vibration conditions, these gaps between parts can easily cause permanent magnets and other parts to loosen and cause failures; therefore, to ensure the reliability requirements of not loosening during movement, the size matching between these parts must be used. Overfilling or compression, and interference fit will cause difficulty in insertion and installation, and the process cannot be realized.

Application content

This application mainly solves the technical problems existing in the above-mentioned prior art and provides a permanent magnet fixing structure.

The above-mentioned technical problems of the present application are mainly solved by the following technical solutions: a permanent magnet fixing structure, including a rotor core, a permanent magnet, and a magnetic barrier strip,

The permanent magnets are installed on the inner surface or the outer surface of the rotor core through two adjacent magnetic isolation pressure strips, and the magnetic isolation pressure strips are in clearance fit with the permanent magnets;

The magnetic isolation bar includes a fixed section assembled in the rotor core and a compression section for compressing the permanent magnet; the fixed section is inserted into the rotor core, and the two are assembled after the assembly is completed. It is further fixed by a fastener provided at the top end of the fixing section; the cross section of the pressing section is a dovetail shape, and the side surface of the permanent magnet connecting with the pressing section matches the shape of the pressing section .

Preferably, the fasteners are two cooperating wedge pieces, and the permanent magnets, the magnetic barrier strips and the rotor core are sealed with glue.

Preferably, the fasteners are two cooperating wedge pieces; the compression section is provided with a first expanded fiber felt, and in the initial state, the outer side of the first expanded fiber felt and the pressure The outer side of the tight section is flush; after the wedge piece is assembled, the first expanded fiber felt expands and solidifies to compress the permanent magnet.

Preferably, the fastener is a second expanded fiber felt arranged in the first groove at the top end of the fixed section. In the initial state, the outer side of the second expanded fiber felt is connected to the outer side of the fixed section. The side surface is flush; the pressing section is provided with a first expanded fiber felt. In the initial state, the outer side of the first expanded fiber felt is flush with the outer side of the pressing section; the permanent magnet is flush with the After the magnetic isolation bead is assembled, the second expanded fiber felt and the first expanded fiber felt are expanded and solidified together to compact the permanent magnet.

Preferably, a plurality of through holes are provided on the pressing section close to the fixed section, and the first expanded fiber felt is provided in the through holes.

Preferably, each of the through holes is uniformly arranged along the axial direction of the magnetic isolation bead, and each of the through holes is arranged coaxially.

Preferably, a second groove is provided on the outer surface of the pressing section close to the fixed section that is in contact with the permanent magnet, and the second expanded fiber felt is arranged in the second groove .

Preferably, the cross section of the fixed section is dovetail shape or T shape.

Preferably, a retaining ring is provided on both sides of the permanent magnet in the axial direction.

In the permanent magnet fixing structure provided by the present invention, the permanent magnet is mounted on the inner surface or the outer surface of the rotor core through two adjacent magnetic isolation pressure strips, and the magnetic isolation pressure strip is in clearance fit with the permanent magnet; The magnetic isolation bar includes a fixed section assembled in the rotor core and a compression section for compressing the permanent magnet; the fixed section is inserted into the rotor core, and the two are assembled after the assembly is completed. It is further fixed by a fastener provided at the top end of the fixing section; the cross section of the pressing section is a dovetail shape, and the side surface of the permanent magnet connecting with the pressing section matches the shape of the pressing section .

In the above structure, the pressing section has a dovetail cross section, and the corresponding side of the permanent magnet and the pressing section needs to be a chamfered structure, so the distance between the dovetails of adjacent pressing sections after assembly It is smaller than the overall width of the permanent magnets, so it can be ensured that the permanent magnets will not fall off from the inner or outer surface of the rotor core; at the same time, the fixing section and the rotor core can be fixed by the fasteners, so The above-mentioned permanent magnet fixing structure has simple process and reliable operation.

In a specific embodiment, the fasteners are two cooperating wedge pieces, and the permanent magnets, the magnetic barrier strips and the rotor core are sealed with glue.

In another specific embodiment, the fasteners are two cooperating wedging pieces, and a first expanded fiber felt is provided on the pressing section. In the initial state, the outer portion of the first expanded fiber felt is The side surface is flush with the outer side surface of the pressing section; after the wedge piece is assembled, the first expanded fiber felt expands and solidifies to compress the permanent magnet.

The above-mentioned wedge structure or expansion jacking structure all make the assembly process of the above-mentioned permanent magnet fixing structure simpler, and the structure is firm after wedge-locking glue-sealing or varnishing expansion, which not only meets the requirements of process convenience, but also meets the requirements of reliability. . In addition, the use of sealing glue or dipping paint for the permanent magnet assembly will produce a protective film on the outer surface of the permanent magnet, which is beneficial to improve the anti-corrosion performance of the permanent magnet.

Description of the drawings

Figure 1 is an overall cross-sectional view of the permanent magnet fixing structure in the first specific embodiment of the present invention;

Fig. 2 is a partial enlarged view of the permanent magnet fixing structure in Fig. 1;

Figure 3 is a diagram of the use state of the wedge in Figure 2;

4 is an overall cross-sectional view of the permanent magnet fixing structure in the second specific embodiment of the present invention;

Fig. 5 is a partial enlarged view of the permanent magnet fixing structure in Fig. 4;

Figure 6 is a cross-sectional view in the direction of A-A in Figure 5;

Figure 7 is a cross-sectional view of another arrangement of the first expanded fiber felt in the second specific embodiment of the present invention;

8 is a partial enlarged view of the permanent magnet fixing structure in the third specific embodiment of the present invention;

Figure 9 is a cross-sectional view of another arrangement of the first expanded fiber felt in the third specific embodiment of the present invention;

Fig. 10 is a cross-sectional view of the second arrangement of the fixing section in the first specific embodiment of the present invention.

The reference signs in Figures 1 to 10 are as follows:

1- rotor core; 2- wedge, 3- permanent magnet; 4- magnetic isolation strip; 5- first expanded fiber felt; 6- second expanded fiber felt.

Detailed ways

The application will be further described below in conjunction with the drawings and specific implementations:

A permanent magnet fixing structure includes a rotor core 1, a permanent magnet 3, and a magnetic isolation pressure strip 4; the permanent magnet 3 is installed on the inner or outer surface of the rotor core 1 through two adjacent magnetic isolation pressure strips 4, that is, the invention has both It is suitable for inner-rotor permanent magnet direct-drive motors and also suitable for outer-rotor permanent magnet direct-drive motors. For the convenience of description, the corresponding drawings of the present invention are the settings of permanent magnet fixed structures in outer-rotor motors.

The magnetic isolation bar 4 includes a fixed section assembled in the rotor core 1 and a compression section for pressing the permanent magnet 3, the fixed section is inserted into the rotor core 1 and slides with a small axial gap with the rotor core 1 They are connected to facilitate the installation of the magnetic isolation bead 4, and the two are further fixed by fasteners arranged at the top of the fixing section after the assembly is completed, so that the magnetic isolation bead 4 and the rotor core 1 are fixedly connected. The axial assembly of the magnetic isolation pressure strip 4 and the rotor core is a small gap sliding, and the specific gap can be 0.2-0.5 mm. Generally, due to the small width of the magnetic barrier bead 4, the fastening position of the magnetic barrier bead 4 and the rotor core 1 is placed on the top of the fixed section.

The cross section of the pressing section is dovetail shape, the side surface of the permanent magnet 3 and the pressing section matches the shape of the pressing section, that is, the permanent magnet 3 in the permanent magnet fixing structure in the outer rotor motor The centripetal surface of the magnetic isolation bead 4 has a chamfered structure, and the centripetal end of the magnetic isolation bead 4 is correspondingly dovetailed. Therefore, after assembly, the distance between the centripetal dovetails of adjacent magnetic isolation bead 4 is less than the width of the permanent magnet 3. Ensure that the permanent magnet 3 will not fall off from the center.

The permanent magnet 3 and the magnetic isolation pressure strip 4 are arranged in a clearance fit to facilitate installation.

The cross section of the above-mentioned fixed section can also be a dovetail shape. In this case, the magnetic isolation bead 4 has a double dovetail structure, but in fact, the cross section can also be T-shaped, as shown in Figure 9 for details. The above-mentioned fixed section is assembled in the dovetail groove or T-shaped groove of the rotor core 1, and the dovetail structure or T-shaped structure can ensure that the magnetic shielding strip 4 will not fall off in the radial direction.

In the axial direction of the motor, both the permanent magnet 3 and the magnetic barrier strip 4 can be made into multiple sections, so that the total length of the permanent magnet 3 matches the rotor core 1.

In addition, a retaining ring can be provided to position the permanent magnet 3 in the axial direction, and it is usually arranged at the outermost axial ends of the permanent magnet 3.

In the above-mentioned permanent magnet fixing structure, the magnetic barrier strip 4 fixes the permanent magnet 1 simply and effectively, and the overall structure process is simple and reliable.

In the first specific embodiment, the fastener is a wedge piece 2, and the two wedge pieces 2 are usually used in conjunction with the same angle, and are respectively driven into the wedge piece axially from the small thickness space of the magnetic barrier strip 4 2 Wedge tight, the angle of the wedge is too small, such as 1 to 2°.

After the wedge piece 2 is assembled, the permanent magnet 3, the magnetic isolation bead 4 and the rotor core 1 are filled with glue to seal, which can further enhance the fastening effect of the magnetic isolation bead 4 on the permanent magnet 3, and it will also be in the permanent magnet 3. A protective film is formed on the outer surface, which is beneficial to the anti-corrosion performance of the permanent magnet 3. The above-mentioned glue filling and sealing is a common glue method in the prior art. For specific operation steps, please refer to the prior art, which will not be repeated here.

In the second specific embodiment, the fastener is still the clinching piece 2, and the two clinching pieces 2 are used in conjunction, and the settings are the same as in the first specific embodiment. But at the same time, a first expanded fiber felt 5 is provided on the pressing section. In the initial state, the outer side of the first expanded fiber felt 5 is flush with the outer side of the pressing section, so that it does not affect the magnetic barrier strip 4 installation; after the assembly of the wedge piece 2 is completed, the first expanded fiber mat 5 can be expanded and solidified by the baking vacuum dipping process to press the permanent magnet 3 tightly.

The above-mentioned materials of the expanded fiber felt and the baking vacuum dipping process are all the prior art, which is not the invention of the present invention, so it will not be repeated here. However, the technical parameters of the first expanded fiber mat can be referred to as follows: when heated to 80°C or 130°C, the thermal expansion rate of the first expanded fiber mat may exceed 50% or 100%.

The above expansion and tightening structure can replace the sealing potting in the above simple wedge structure, and it also has the advantages of convenient assembly process of the magnetic isolation bead 4 and better fastening effect of the integral permanent magnet fixing structure, which not only meets the requirements of process convenience , And meet the reliability requirements of operation.

Specifically, the above-mentioned first expanded fiber felt 5 can be arranged in two ways:

One is that a number of through holes are provided on the compression section near the fixed section, and the first expanded fiber felt 5 is provided in the through holes. Further, each through hole can be arranged along the magnetic barrier strip. The axial direction of 4 is uniformly arranged, and each of the through holes is arranged coaxially.

The other is that a second groove is provided on the outer surface of the pressing section close to the fixed section that is in contact with the permanent magnet 3, and the first expanded fiber felt 5 is provided in the second groove. The second groove may be provided on only one side surface of the pressing section, or may be provided on both side surfaces at the same time.

In a third specific embodiment, the fastener is a second expanded fiber mat 6 arranged in the first groove at the top end of the fixing section. In the initial state, the outer surface of the second expanded fiber mat 6 is in contact with the The outer side of the fixed section is flush; at the same time, the first expanded fiber felt 5 is still provided on the pressing section. In the initial state, the outer side of the first expanded fiber felt 5 is flush with the outer side of the pressing section After the permanent magnet 3 and the magnetic barrier strip 4 are assembled, the second expanded fiber felt 6 and the first expanded fiber felt 5 are expanded and dipped and cured together to press the permanent magnet 3 tightly.

The material of the above-mentioned second expanded fiber mat is also in the prior art, and it can be specifically the same as the material of the above-mentioned first expanded fiber mat, which is not the inventive point of the present invention, so it will not be repeated here. At the same time, the technical parameters of the second expanded fiber mat can refer to the first expanded fiber mat.

In the third specific embodiment, the second expanded fiber felt 6 is used to replace the wedge piece 2 in the first two specific embodiments. The installation process corresponding to the permanent magnet fixing structure is further simplified, and the structure is firm, which satisfies The requirement of process convenience also satisfies the requirement of application reliability.

The thickness of the first expanded fiber mat 5 and the second expanded fiber mat 6 is relatively thin, and may be 1 mm.

In the third specific embodiment, the first expanded fiber felt 5 can also be arranged in two ways, and the details are the same as those in the second specific embodiment, which will not be repeated.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

The above descriptions are only preferred embodiments of this application, and are not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection of this application. Within range.

Claims

A permanent magnet fixing structure, comprising a rotor core, a permanent magnet and a magnetic isolation pressure strip, which is characterized in that:

The permanent magnets are installed on the inner surface or the outer surface of the rotor core through two adjacent magnetic isolation pressure strips, and the magnetic isolation pressure strips are in clearance fit with the permanent magnets;

The magnetic isolation bar includes a fixed section assembled in the rotor core and a compression section for compressing the permanent magnet; the fixed section is inserted into the rotor core, and the two are assembled after the assembly is completed. It is further fixed by a fastener provided at the top end of the fixing section; the cross section of the pressing section is a dovetail shape, and the side surface of the permanent magnet connecting with the pressing section matches the shape of the pressing section .
The permanent magnet fixing structure according to claim 1, characterized in that:

The fasteners are two cooperating wedge pieces, and the permanent magnets, the magnetic isolation bar and the rotor core are sealed with glue.
The permanent magnet fixing structure according to claim 1, characterized in that:

The fasteners are two cooperating wedge pieces; the pressing section is provided with a first expanded fiber felt. In the initial state, the outer side of the first expanded fiber felt and the pressing section The outer side is flush; after the wedge piece is assembled, the first expanded fiber felt expands and solidifies to compress the permanent magnet.
The permanent magnet fixing structure according to claim 1, characterized in that:

The fastener is a second expanded fiber felt arranged in the first groove at the top of the fixed section. In the initial state, the outer side of the second expanded fiber felt is flush with the outer side of the fixed section The pressing section is provided with a first expanded fiber felt, in the initial state, the outer side of the first expanded fiber felt is flush with the outer side of the pressing section; the permanent magnet and the magnetic isolation After the bead assembly is completed, the second expanded fiber felt and the first expanded fiber felt are expanded and solidified together to compact the permanent magnet.
The permanent magnet fixing structure according to claim 3 or 4, characterized in that:

A number of through holes are provided on the compression section close to the fixed section, and the first expanded fiber felt is provided in the through holes.
The permanent magnet fixing structure according to claim 5, characterized in that:

Each of the through holes is uniformly arranged along the axial direction of the magnetic isolation bead, and each of the through holes is arranged coaxially.
The permanent magnet fixing structure according to claim 3 or 4, characterized in that:

A second groove is provided on the outer side surface of the pressing section close to the fixed section that is in contact with the permanent magnet, and the second expanded fiber felt is provided in the second groove.
The permanent magnet fixing structure according to any one of rights 1-4, characterized in that:

The cross section of the fixed section is dovetail shape or T shape.
The permanent magnet fixing structure according to claim 8, characterized in that:

A retaining ring is provided on both sides of the permanent magnet in the axial direction.