CN116418144A

CN116418144A - Permanent magnet motor

Info

Publication number: CN116418144A
Application number: CN202310371495.8A
Authority: CN
Inventors: 李敏龙; 施晶鑫; 陶然; 胡彧; 钱宇昊; 王小珍; 闻汇; 李曙光
Original assignee: Zhejiang Lover Health Science and Technology Development Co Ltd
Current assignee: Zhejiang Lover Health Science and Technology Development Co Ltd
Priority date: 2023-04-10
Filing date: 2023-04-10
Publication date: 2023-07-11

Abstract

The invention belongs to the technical field of motors, and particularly relates to a permanent magnet motor, which comprises a stator and a rotor, wherein an air gap is formed between the stator and the rotor, the rotor comprises a rotor iron core and permanent magnets, the rotor iron core comprises a plurality of first axial sections which are sequentially distributed at intervals along the axial direction of the rotor iron core, the interval between every two adjacent first axial sections is a second axial section, and the permanent magnets are respectively distributed on each first axial section. The permanent magnet motor of the invention arranges the permanent magnets of the rotor along the axial direction at a certain distance, and can fully utilize the air gap edge effect at the end part of the permanent magnets, so that the utilization rate of the permanent magnets is increased, thereby reducing the material cost of the motor.

Description

Permanent magnet motor

Technical Field

The invention belongs to the technical field of motors, and particularly relates to a permanent magnet motor.

Background

Compared with an asynchronous motor, the permanent magnet synchronous motor has the advantages of high torque density, high efficiency, small starting current and the like, and is widely applied to the industries of energy, traffic, manufacturing, medical treatment and the like. The permanent magnet is a core component of the permanent magnet motor, is also a fundamental place of high cost of the permanent magnet motor, and the increasing rare earth price makes the economic defect of the permanent magnet motor more and more obvious, so that the permanent magnet motor is one of important factors for restricting the overall popularization of the permanent magnet motor.

For general civil scenes, compared with performance indexes such as torque density and efficiency, the economical efficiency of the motor is greatly focused by enterprises. Therefore, the utilization rate of the permanent magnet is improved, so that the permanent magnet in unit volume generates larger torque as much as possible, and the permanent magnet has more remarkable practical value. In addition, permanent magnets are also subject to high temperature demagnetization risks, and how to effectively dissipate heat from the motor component with the permanent magnets is a problem that needs additional consideration for such motors.

Disclosure of Invention

Based on the above-mentioned drawbacks and deficiencies of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems of the prior art, in other words, to provide a permanent magnet motor which meets one or more of the above-mentioned needs.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

the utility model provides a permanent magnet motor, includes stator and rotor, and the rotor is located the stator, has the air gap between stator and the rotor, and the rotor includes rotor core and permanent magnet, rotor core includes the first axial section of several sections of following its axial interval distribution in proper order, and the interval between the adjacent first axial section is the second axial section, and the permanent magnet is disposed respectively in each first axial section.

Preferably, the second axial section is made of a non-magnetic conductive material.

Preferably, the maximum outer diameter of the integral structure formed by the first axial section and the permanent magnet is not smaller than the outer diameter of the second axial section.

Preferably, the outer ring surface of the second axial section is provided with a plurality of grooves uniformly distributed along the circumferential direction of the second axial section, and the central axes of the grooves coincide with the central axes of the corresponding permanent magnets.

Preferably, the surface of the rotor core is provided with a plurality of rotor grooves uniformly distributed along the circumferential direction, and the rotor grooves extend along the axial direction of the rotor and penetrate at least one end of the rotor.

Preferably, the central axes of the rotor grooves coincide with the central axes of adjacent permanent magnets in the same first axial section.

Preferably, the rotor groove is used for mounting a non-magnetic conductive piece;

the rotor groove comprises a notch facing the air gap and a groove body extending towards the radial inner side to form a semi-closed groove structure; the width of the notch is smaller than the width of the top of the groove body adjacent to the notch, and the width of the top of the groove body is larger than the width of the bottom of the groove body far away from the notch, so that the mounted non-magnetic conductive piece is fixed in the radial direction and the circumferential direction.

As a preferred scheme, the non-magnetic conductive member comprises an axially extending cutting and a radial protruding block arranged on the cutting, the structure of the cutting is matched with the structure of the groove body and the groove opening, and when the cutting is inserted into the rotor groove, the outer diameter of the cutting is flush with the outer diameter of the rotor core; the radial protruding blocks are larger than the notches in size so as to limit the radial protruding blocks to the rotor core in the radial direction;

the radial projections are distributed corresponding to each second axial section of the rotor core; the axial length of the radial projection is equal to the axial length of the second axial section of the rotor core to abut the permanent magnets adjacent to both axial sides thereof.

Preferably, the cutting is divided into several sections along the axial direction, and each section of cutting corresponds to only one second axial section.

Preferably, the cutting is in clearance fit with the bottom of the groove body to form an axially extending ventilation channel.

Compared with the prior art, the invention has the beneficial effects that:

(1) The permanent magnet motor of the invention arranges the permanent magnets of the rotor along the axial direction at a certain distance, and can fully utilize the air gap edge effect at the end part of the permanent magnets, so that the utilization rate of the permanent magnets is increased, thereby reducing the material cost of the motor;

(2) The permanent magnet motor is provided with the non-magnetic conductive material or the non-magnetic conductive piece in the second axial section, so that the permanent magnet is axially isolated and fixed;

(3) When the permanent magnet adopts an integral annular structure, the permanent magnet is convenient to manufacture and magnetize, has the advantage of low cost, is sleeved on the first axial section of the rotor core along the axial direction on the basis, and is positioned and fixed by means of the second axial section or a non-magnetic conductive piece arranged on the second axial section, so that the assembly precision and the assembly efficiency of the permanent magnet can be ensured;

(4) When the rotor core adopts a tooth slot structure, the motor can further utilize the salient pole effect, electromagnetic torque can be improved to a certain extent, and speed regulation performance can be improved;

(5) The invention also forms an air channel at the bottom of the rotor groove, thereby effectively relieving the heat of the rotor and the whole motor.

Drawings

Fig. 1 is an overall construction diagram of a permanent magnet motor according to embodiment 1 of the present invention;

fig. 2 is a stator structure diagram of a permanent magnet motor according to embodiment 1 of the present invention;

fig. 3 is a construction diagram of a rotor according to embodiment 1 of the present invention;

fig. 4 is a construction diagram of a rotor according to embodiment 2 of the present invention;

fig. 5 is a construction diagram of a rotor according to embodiment 3 of the present invention;

fig. 6 is an exploded view of a rotor structure of embodiment 3 of the present invention;

fig. 7 is a partial structural view of a rotor structure of embodiment 3 of the present invention;

fig. 8 is a schematic diagram of a rotor structure according to embodiment 3 of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention, specific embodiments of the present invention will be described below with reference to the accompanying drawings. It is evident that the drawings in the following description are only examples of the invention, from which other drawings and other embodiments can be obtained by a person skilled in the art without inventive effort.

Example 1:

as shown in fig. 1, the permanent magnet motor of the present embodiment includes a rotor 1 and a stator 2 located outside the rotor 1, with an air gap 3 between the rotor 1 and the stator 2.

As shown in fig. 2, the stator 2 includes a stator core 21 and a stator winding 23, and an inner wall of the stator core 21 has a plurality of axially extending stator slots 22 uniformly distributed along a circumferential direction thereof, the stator slots 22 for accommodating the stator winding 23.

As shown in fig. 3, the rotor 1 includes a rotor core 11 and permanent magnets 12, the rotor core includes two first axial sections 1a (not limited to two sections in the drawing, and specifically designed according to practical application requirements) that are sequentially spaced apart along the axial direction thereof, the spacing between adjacent first axial sections 1a is a second axial section 1b, the permanent magnets 12 are respectively disposed on each first axial section 1a, and the second axial sections 1b are made of a non-magnetic material. Wherein, the external diameter of the second axial section 1b is smaller than or equal to the maximum external diameter of the integral structure formed by the first axial section and the permanent magnets, and the two axial sides of the second axial section 1b are respectively adjacent to the permanent magnets 12 on the two sides, so that the permanent magnets on the two sides are isolated, and the flux linkage intersection is avoided.

The rotor core 11 of the present embodiment is coaxially mounted with a rotary shaft 13.

The permanent magnet 12 of the present embodiment is a plate-like sector structure assembled only in the first axial section 1a of the rotor core. The permanent magnets 12 can be installed simultaneously from both sides of the motor, and are lower in cost and more convenient to install due to their smaller structure than conventional permanent magnets.

Example 2:

the permanent magnet motor of the present embodiment is different from embodiment 1 in that: the structure of the non-magnetic ring is different.

Specifically, as shown in fig. 4, the outer annular surface of the second axial section has a plurality of grooves 1b1 uniformly distributed along the circumferential direction thereof, so that the non-magnetically conductive ring forms a plurality of teeth 152. The central axes of the grooves are coincident with the central axes of the corresponding permanent magnets, namely the central axes of the convex teeth are coincident with the central axes of the two permanent magnets which are adjacent to the convex teeth and are positioned in the same first axial section;

the motor torque has two components, one is caused by magnetic linkage and the other is caused by salient pole, and the magnitude of the salient pole ratio can influence the magnitude of the output reluctance torque of the motor. Because of the groove structure of the second axial section, the whole body is not a cylinder with the same radius, and the air gap of the motor is uneven, namely the effective air gaps of a straight axis (d axis) and a quadrature axis (q axis) are different, so that the salient pole effect can be enhanced, the motor torque can be increased, and the speed regulation performance of the motor can be enhanced.

Other structures can be referred to embodiment 1.

Example 3:

the permanent magnet motor of the present embodiment is different from embodiment 1 in that:

as shown in fig. 5-8, the surface of the rotor core has a plurality of rotor slots 112 uniformly distributed along the circumferential direction thereof, the rotor slots 112 extending in the axial direction of the rotor and penetrating through both ends of the rotor, the central axes of the rotor slots coinciding with the central axes of adjacent permanent magnets in the same first axial section. Wherein the rotor slots 112 are used to mount the non-magnetic conductive members 15.

Specifically, the rotor groove 112 includes a groove body and a notch distributed in the radial direction of the rotor, that is, a notch facing the air gap and a groove body extending toward the radial inside, forming a semi-closed groove structure; the width of the notch is smaller than the width of the top of the groove body adjacent to the notch, and the width of the top of the groove body is larger than the width of the bottom of the groove body far away from the notch, so that the mounted non-magnetic conductive piece 15 is fixed in the radial direction and the circumferential direction. The tank body of the embodiment is of an inverted trapezoid structure.

The non-magnetic conductive piece 15 comprises an axially extending cutting 151 and a radial lug 153 arranged on the cutting 151, the structure of the cutting 151 is matched with the structure of the groove body and the groove opening, when the cutting 151 is inserted into the rotor groove 112, the outer diameter of the cutting 151 is flush with the outer diameter of the rotor core; the radial projection 153 has a size larger than that of the notch, so that the radial projection is limited to the rotor core radially and cannot move radially, thereby ensuring the stability of connection. In addition, the radial projections 153 are distributed corresponding to the second axial section, and the axial length of the radial projections is equal to the axial length of the second axial section of the rotor core so as to be adjacent to the permanent magnets adjacent to both sides thereof. The groove structure 1b2 is still formed between adjacent radial projections 153 in the same circumferential direction.

The insert and the radial bump in this embodiment are made of non-magnetic material, so that the salient pole effect can be effectively improved, and the rotor efficiency can be improved.

After the non-magnetic conductive member 15 and the rotor slot 112 are nested, an axial air channel 112a with an inverted trapezoid cross section is left at the bottom of the rotor slot 112, and the relationship between the area S1 of the axial air channel and the area S2 of the rotor slot is: under the constraint relationship, S1 is more than 0 and S2, the stability of the connection between the non-magnetic conductive piece 15 and the rotor groove 112 can be ensured, and the axial ventilating duct 112a can have enough cooling effect on the rotor.

In addition, the central axes of the radial projections 153 coincide with the central axes of the two permanent magnets adjoining and in the same first axial section.

The fixed end plates 14 are respectively mounted at both ends of the rotor core of the present embodiment, and the fixed end plates 14 include a rotation shaft groove 141 and a ventilation hole 142, which are assembled in front and rear of the rotor core 11, so that the movement of the non-magnetic conductive member 15 in the axial direction can be restricted, thereby restricting the movement of the non-magnetic conductive member together with the rotor groove 112. Moreover, the shape, position and size of the vent holes 142 on the fixed end plate 14 are the same as those of the axial air duct 112a, so that the vent holes 142 in the embodiment have an inverted trapezoid structure and are matched with the axial air duct 112a to form an air gap 3 of the whole rotor;

during the operation of the motor, the ventilation hole 142 and the axial ventilation channel 112a can well cool the motor rotor, so that the output efficiency of the rotor is increased, the power consumption is reduced, the heating of the rotor is reduced, the service life is prolonged, or the volume of the rotor is reduced; the axial sectional structural design can bring larger torque and better speed regulation performance for the motor rotor.

Other structures can be referred to embodiment 1.

Example 4:

the permanent magnet motor of the present embodiment is different from embodiment 3 in that:

the cutting is divided into a plurality of sections along the axial direction, each section of cutting corresponds to only one second axial section, and the cutting is installed in a segmented mode, so that the defect that the permanent magnet cannot be installed in the axial direction due to blocking of the radial protruding blocks can be overcome, and the problem that the permanent magnet of each first axial section cannot be installed in the axial direction due to the cutting of an integral structure is solved;

other structures can be referred to embodiment 1.

Example 5:

the permanent magnet adopts an integral annular structure, is convenient to manufacture and magnetize, has the advantage of low cost, is sleeved on the first axial section of the rotor core along the axial direction on the basis, and is positioned and fixed by means of the non-magnetic ring structure of the second axial section of the rotor core, so that the assembly precision and the assembly efficiency of the permanent magnet can be ensured;

other structures can be referred to embodiment 1.

The foregoing is only illustrative of the preferred embodiments and principles of the present invention, and changes in specific embodiments will occur to those skilled in the art upon consideration of the teachings provided herein, and such changes are intended to be included within the scope of the invention as defined by the claims.

Claims

1. The utility model provides a permanent magnet motor, includes stator and rotor, and the rotor is located the stator, has the air gap between stator and the rotor, and the rotor includes rotor core and permanent magnet, its characterized in that, rotor core includes the first axial section of several sections that distribute along its axial interval in proper order, and the interval between the adjacent first axial section is the second axial section, and the permanent magnet is disposed respectively in each first axial section.

2. A permanent magnet machine according to claim 1 wherein the second axial section is of a non-magnetically permeable material.

3. A permanent magnet machine according to claim 2, wherein the maximum outer diameter of the integral structure of the first axial section and permanent magnets is not smaller than the outer diameter of the second axial section.

4. A permanent magnet machine according to claim 3, wherein the outer annular surface of the second axial section has a plurality of grooves evenly distributed along its circumference, the central axes of the grooves coinciding with the central axes of their corresponding permanent magnets.

5. A permanent magnet machine according to claim 1, wherein the surface of the rotor core has a plurality of rotor slots evenly distributed along its circumference, the rotor slots extending in the axial direction of the rotor and penetrating at least one end of the rotor.

6. A permanent magnet machine according to claim 5 wherein the central axis of the rotor slot coincides with the central axis of an adjacent permanent magnet in the same first axial segment.

7. A permanent magnet machine according to claim 6 wherein the rotor slot is for mounting a non-magnetically permeable member;

8. The permanent magnet machine of claim 7 wherein the non-magnetic conductive member comprises an axially extending insert and a radial projection disposed on the insert, the insert being configured to mate with the slot body and the slot opening, the insert having an outer diameter flush with an outer diameter of the rotor core when the insert is inserted into the rotor slot; the radial protruding blocks are larger than the notches in size so as to limit the radial protruding blocks to the rotor core in the radial direction;

9. A permanent magnet machine according to claim 8 wherein the slips are divided axially into a plurality of segments, each corresponding to only one second axial segment.

10. A permanent magnet machine according to claim 8 wherein the insert is in clearance fit with the bottom of the housing to define an axially extending air passage.