WO2022116532A1

WO2022116532A1 - Rotor and permanent magnet electric motor

Info

Publication number: WO2022116532A1
Application number: PCT/CN2021/104366
Authority: WO
Inventors: 韩永杰; 刘钧; 杨深; 蒋奎; 纪科星
Original assignee: 上海威迈斯新能源有限公司
Priority date: 2020-12-04
Filing date: 2021-07-02
Publication date: 2022-06-09
Also published as: CN112421826A

Abstract

Disclosed in the present invention are a rotor and a permanent magnet electric motor. The rotor comprises an iron core and a magnetic steel groove group, wherein the magnetic steel groove group comprises first magnetic steel grooves, magnetic steel and a magnetic bridge; each first magnetic steel groove is correspondingly provided with an air groove, each air groove is provided on the side of the two first magnetic steel grooves that is sandwiched by the two first magnetic steel grooves, and the air grooves are close to corners of the magnetic steel; each first magnetic steel groove comprises a first groove wall and a second groove wall, and the magnetic steel comprises a first end and a second end, the first end being arranged towards a V-shaped opening, and the second end being arranged towards a V-shaped tip; and the air grooves comprise a first air groove close to a corner at the first end and a second air groove close to a corner at the second end. Compared with the prior art, the present invention can relieve a demagnetization effect of a demagnetization magnetic field on the corners of magnetic steel, and in addition, does not influence the output torque of the permanent magnet electric motor.

Description

Rotor and Permanent Magnet Motors

technical field

The invention relates to the field of permanent magnet motors, in particular to a rotor and permanent magnet motors.

Background technique

Environmental pollution and energy crisis have prompted the rapid development of the new energy vehicle industry, especially the booming electric vehicle industry. As one of the key executive components of the electric vehicle, the permanent magnet motor for vehicle drive is very important to the performance of the whole vehicle. Due to the advantages of high power density and high efficiency, permanent magnet motors have been widely used in the field of vehicle drive permanent magnet motors. Permanent magnet motors have the advantages of simple structure, small size, low loss, high efficiency and easy control, etc. advantage. In order to improve the power density of the drive system, a permanent magnet motor and a reducer are usually used to provide driving force for electric vehicles, or a three-in-one assembly that is highly integrated with a permanent magnet motor, a reducer and a permanent magnet motor controller.

However, due to the special operating conditions of electric vehicles, the permanent magnet motor needs to have a high torque density, that is to say, the permanent magnet motor needs a large torque and a small volume of the permanent magnet motor; in the existing In the technology, some will use the method of stacking the permanent magnet motor to increase the output torque of the permanent magnet motor, but it will also increase the volume of the permanent magnet motor; The output torque of the motor, but the high-performance magnetic steel will also increase the cost of the permanent magnet motor, and the high-performance magnetic steel will also lead to the saturation of the magnetic circuit, which will increase the iron loss and at the same time increase the magnetic steel remanence. The improvement of torque performance is limited, and when it reaches a certain level, the torque performance of the permanent magnet motor cannot be further improved.

At the same time, in the prior art, when the amount of magnetic steel is the same, the thickness of the rotor magnetic bridge will affect the magnetic flux leakage of the magnetic steel. The larger thickness of the magnetic bridge increases the magnetic flux leakage, thereby reducing the output torque of the permanent magnet motor. , so in order to obtain a larger output torque, it is necessary to reduce the thickness of the magnetic bridge as much as possible, but if the thickness of the magnetic bridge is too small, the demagnetization state of the permanent magnet motor will be aggravated, which is mainly due to the small thickness of the magnetic bridge. , inhibits the trend of the demagnetization magnetic field, so that the demagnetization magnetic field tends to concentrate on the magnet steel of the permanent magnet motor, so that the demagnetization state of the magnetic field is intensified. The increase needs to increase the amount of rare earth, which will increase the cost of magnet steel, thereby increasing the total cost of permanent magnet motor; the amount of magnet steel can also be increased to reduce the demagnetization rate of magnet steel and ensure the stability of permanent magnet motor, but the amount of magnet steel The increase in the amount of magnetic steel will also increase the cost of the permanent magnet motor, and the increase in the amount of magnetic steel will also make the mechanical strength of the rotor under the action of centrifugal force worse.

Therefore, it is necessary to design a rotor with excellent anti-demagnetization performance to ensure the output torque of the permanent magnet motor without increasing the volume and cost.

SUMMARY OF THE INVENTION

The present invention provides a rotor and a permanent magnet motor, which can design a rotor with excellent anti-demagnetization performance without increasing the volume and cost and ensuring the output torque of the permanent magnet motor.

The technical scheme adopted in the present invention is: a rotor, comprising an iron core and a magnetic steel slot group, wherein the magnetic steel slot group includes two first magnetic steels distributed in a V shape and the V-shaped tip direction is toward the center of the iron core There is a magnetic steel with a rectangular cross-section in the first magnetic steel groove, and a magnetic bridge is located at the V-shaped tip between the two first magnetic steel grooves, and each of the first magnetic steel grooves corresponds to An air slot is arranged on the ground, the air slot is arranged on one side where the two first magnetic steel slots are sandwiched, and the air slot is close to the corner of the magnetic steel.

Further, the first magnetic steel slot includes a first slot wall and a second slot wall extending from the tip of the V shape to the opening direction, and the magnetic steel is embedded between the first slot wall and the second slot wall. the first slot wall is arranged on one side sandwiched between the two first magnetic steel slots, and the magnetic steel includes a first end portion and a second end portion that are perpendicular to the first slot walls, so The first end is arranged toward the V-shaped opening, and the second end is arranged toward the V-shaped tip; the air slot includes a first air slot, and the first air slot is close to the first air slot of the magnetic steel. Corner at one end.

Further, the minimum vertical distance D1 from the groove wall of the first air groove to the first groove wall is 0.2 mm to 0.3 mm; the vertical distance D2 from the center of the first air groove to the first end portion is 0.2mm to 0.3mm; the first magnetic steel slot further includes a third slot wall connected with the first slot wall and deflected toward the inner side of the angle between the two first magnetic steel slots, the first air The minimum vertical distance D3 of the groove wall of the groove from the third groove wall is 0.2 to 0.3 mm.

Further, the air slot further includes a second air slot, and the second air slot is close to the corner at the second end of the magnetic steel.

Further, the minimum vertical distance D4 from the groove wall of the second air groove to the first groove wall is 0.2 mm to 0.4 mm; the vertical distance D5 from the center of the second air groove to the second end 0.6mm to 0.8mm.

Further, the first air groove and the second air groove are elliptical.

Further, the length of the long axis L1 of the first air groove is 0.5mm to 0.6mm, the length of the short axis L2 is 0.3mm to 0.4mm, and the angle A between the long axis and the first groove wall is 20 ° to 35°; the length of the long axis L3 of the second air groove is 0.6 mm to 0.7 mm, the length of the short axis L4 is 0.3 mm to 0.4 mm, and the length of the long axis and the first groove wall is clamped Angle B is 20° to 35°.

Further, the magnetic steel groove group also includes two second magnetic steel grooves distributed in a V shape and with the V-shaped tip direction facing the center of the iron core, and the second magnetic steel grooves are arranged on the first magnetic steel. The side of the slot away from the center of the core.

Further, the included angle between the two first magnetic steel grooves is less than 15°.

A permanent magnet motor comprising the rotor.

Compared with the prior art, in the present invention, the first convex portion is arranged in the magnetic steel groove of the rotor iron core, and the arrangement of the first convex portion can play a role of drainage. A convex part can drain the demagnetization magnetic field, relieve the demagnetization effect of the demagnetization magnetic field on the corners of the magnetic steel, and at the same time, it will not affect the output torque of the permanent magnet motor.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the structural schematic diagram of the magnetic steel groove on the iron core in the present invention;

2 is a schematic diagram of an enlarged structure of the present invention A;

FIG. 3 is a schematic diagram of an enlarged structure of the present invention B. FIG.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In the present application, the rotor includes an iron core formed by stacking a plurality of punched sheets. The iron core includes a plurality of magnetic poles distributed along its circumferential direction, and each magnetic pole includes a magnetic steel slot group.

As shown in FIG. 1 , one of the magnetic steel groove groups of the iron core is taken as an example for illustration. The magnetic steel groove group includes two first magnetic steel grooves 1 and two second magnetic steel grooves 2 .

Among them, the two first magnetic steel slots 1 are symmetrically distributed in a V shape, and the V-shaped tips formed by the two first magnetic steel slots 1 extend toward the center of the iron core, and the openings face the outside of the iron core. The steel slot 1 is located between the ends of the tip to form a first magnetic bridge 11. Each first magnetic steel slot 1 is embedded with a magnetic steel 3, and the magnetic steel 3 is fixed to the first magnetic steel slot 1 by gluing. central position.

Further, the two second magnetic steel slots 2 are also distributed in a V shape, and the second magnetic steel slots 2 are arranged above the first magnetic steel slot 1, that is, on the outer side in the radial direction of the first magnetic steel slot 1, and the two The V-shaped tip formed by the second magnetic steel slots 2 extends toward the center of the iron core, and the opening faces the outside of the iron core. The two second magnetic steel slots 2 are located between the ends of the tips to form a second magnetic bridge 21. The second magnetic steel slot 2 is also embedded with a magnetic steel 3, and the magnetic steel 3 is fixed in the middle position of the second magnetic steel slot 2 by gluing; at the same time, the first magnetic steel slot 1 and the second magnetic steel slot There is a certain interval between 2, and the first and second magnetic steel slots are arranged along the quadrature axis magnetic circuit of the permanent magnet motor, which helps to reduce the influence of the magnetic steel slot on the quadrature axis inductance of the permanent magnet motor, thereby ensuring permanent The reluctance torque of the magneto is conducive to alleviating the saturation of the quadrature-axis magnetic circuit and increasing the utilization rate of the reluctance torque. In addition, a certain distance between the two layers of magnetic steel is also conducive to alleviating the demagnetization effect of the demagnetizing magnetic field on the magnetic steel. .

Preferably, the included angle between the two first magnetic steel slots 1 is less than 15°, so that the utilization rate of the reluctance torque can be ensured.

Further, the first magnetic steel slot 1 includes a first slot wall 15 and a second slot wall 16 extending from the tip of the V-shape to the opening direction, and the first slot wall 15 and the second slot wall 16 are arranged oppositely, wherein the first slot wall 15 and the second slot wall 16 are opposite. The slot wall 15 is arranged on the inside of the V-shaped opening, that is, on the side where the two first magnetic steel slots 1 are sandwiched, while the second slot wall 16 is arranged on the outside of the V-shaped opening; 1. Between the second groove walls, the two sides of the magnetic steel 3 are in contact with the first groove wall 15 and the second groove wall 16, and the magnetic steel 3 also includes a first end 31 and a second end 32. The first and second ends are arranged at an angle with the first and second magnets, which are vertical in this embodiment, the first end 31 is arranged toward the opening of the V-shape, and the second end 32 is arranged toward the V-shape and the first magnetic steel slot 1 also includes a third slot wall 17, the third slot wall 17 is connected with the first slot wall 15, and the third slot wall 17 faces the angle between the two first magnetic steel slots 1 The inner side is deflected by a certain angle, and the connection between the third slot wall 17 and the first slot wall 15 is arranged near the magnetic steel 3 .

The rotor in the present application is provided with a plurality of groups of air slots 4 , and each group of air slots 4 is arranged in a one-to-one correspondence with the first magnetic steel slot 1 , that is, a set of corresponding air slots is arranged near each first magnetic steel slot 1 . 4. The air slot 4 is arranged on the side where the two first magnetic steel slots 1 are sandwiched, and the air slot 4 is arranged at the corner close to the magnetic steel 3. Under the action of the air slot 4, the magnetic steel 3 is at the most The anti-demagnetization performance under severe demagnetization conditions is improved, the demagnetization rate is significantly reduced, the output torque is guaranteed to a certain extent, and the torque ripple is relatively small.

Further, as shown in FIG. 2 , each group of air slots 4 includes a first air slot 41 and a second air slot 42 ; wherein, taking the first air slot 41 as an example, the first air slot 41 is arranged close to the first magnetic The upper corner of the magnetic steel 3 in the steel slot 1, that is, the corner of the first end 31 close to the magnetic steel 3, and the minimum vertical distance D1 between the slot wall of the first air slot 41 and the first slot wall 15 is 0.2mm to 0.3mm, the vertical distance D2 from the center of the first air groove 41 to the first end 31 is 0.2mm to 0.3mm, and the minimum vertical distance D3 between the groove wall of the first air groove 41 and the third groove wall 17 0.2mm to 0.3mm.

Such a design avoids the problem that the first air slot 41 is too close to the slot wall of the first magnetic steel slot 1 to affect the mechanical strength of the rotor, and increases the difficulty of iron core production and processing, and avoids the distance between the first air slot 41 and the first air slot 41. If the groove wall of the magnetic steel slot 1 is too far, the magnetic leakage of the magnetic steel 3 will be increased, which is not conducive to improving the magnetic steel working point at the corners of the magnetic steel, resulting in the problem that the anti-demagnetization ability of the magnetic steel 3 is reduced.

Further, as shown in FIG. 3 , the second air groove 42 is arranged near the corner of the second end 32 of the magnetic steel 3 in the first magnetic steel groove 1 , and the groove wall of the second air groove 42 is located at a distance from the first magnetic steel groove 1 . The minimum vertical distance D4 of a slot wall 15 is 0.2 mm to 0.4 mm, and the vertical distance D5 between the center of the second air slot 42 and the second end 32 is 0.6 mm to 0.8 mm.

Such a design avoids that the second air slot 42 is too close to the slot wall of the first magnetic steel slot 1 to affect the mechanical strength of the rotor, and increases the difficulty of iron core production and processing. If the groove wall of the magnetic steel slot 1 is too far, the magnetic leakage of the magnetic steel 3 will be increased, which is not conducive to improving the magnetic steel working point at the corners of the magnetic steel, resulting in the problem that the anti-demagnetization ability of the magnetic steel 3 is reduced.

Preferably, the first air slot 41 and the second air slot 42 in the present application are both elliptical, because the elliptical air slot has a more obvious effect of suppressing demagnetization of the magnetic steel than other shapes.

Further, the first air groove 41 is elliptical, and the length of the long axis L1 is 0.5 mm to 0.6 mm, the length of the short axis L2 is 0.3 mm to 0.4 mm, and the angle between the long axis and the first groove wall 15 is A is 20° to 35°; the second air groove 42 is elliptical, the length of the long axis L3 is 0.6mm to 0.7mm, the length of the short axis L4 is 0.3mm to 0.4mm, and the long axis is connected to the first groove wall The included angle B of 15 is 20° to 35°; this setting makes the size of the air slot just right, and avoids that the size of the air slot is too small, so that the demagnetization rate near the corner of the magnetic steel cannot be effectively relieved, and the size of the air slot is avoided. If it is too large, it will affect the mechanical strength of the place, and cause the problem of low output torque of the permanent magnet motor. At the same time, the relative position between the elliptical air slot and the magnetic steel slot can achieve the best anti-demagnetization performance.

Further, the shape of the air slot can also be set to be circular or other irregular shapes.

The application also proposes a permanent magnet motor, which includes the rotor proposed in the application.

After experiments, a control experiment was carried out with two sets of permanent magnet motors with the same number and V-shaped arrangement of rotors, one set of conventional permanent magnet motors with conventional air slot design, and the other set of permanent magnet motors with the air slot design of the present application. For the motor, the demagnetization of the magnetic steel under the same severe conditions is as follows:

Traditional permanent magnet motor: the demagnetization rates of the magnets in the left and right first magnet slots are 2.33% and 2.37%, respectively, and the demagnetization positions of the magnets are mainly concentrated at the corners;

The permanent magnet motor of the present application: the demagnetization rates of the magnets in the left and right first magnet steel slots are 1.89% and 1.91% respectively, the demagnetization positions are concentrated at the corners, and the demagnetization area is reduced.

After testing and comparison, the traditional permanent magnet motor and the permanent magnet motor in this application under the same conditions, the working conditions of the two are: the traditional motor, the average torque is 220.1183Nm, and the torque ripple is 3.69%; For the motor, the average torque is 220.1039Nm and the torque ripple is 3.66%.

It can be seen from the above that in the case of greatly reducing the demagnetization rate of the magnetic steel, the output torque of the permanent magnet motor in the present application and the traditional permanent magnet motor are basically unchanged, and the output pulsation is consistent, and the setting of the present application has quite excellent practical value. .

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims

A rotor includes an iron core and a magnetic steel slot group, the magnetic steel slot group includes two first magnetic steel slots distributed in a V-shape and the V-shaped tip direction is toward the center of the iron core, the first magnetic steel slot A magnetic steel with a rectangular cross-section is arranged in the groove, and a magnetic bridge is located between the two first magnetic steel grooves at the V-shaped tip. It is characterized in that each of the first magnetic steel grooves is correspondingly provided with air A slot, the air slot is arranged on one side where the two first magnetic steel slots are sandwiched, and the air slot is close to the corner of the magnetic steel.
The rotor according to claim 1, wherein the first magnet steel slot includes a first slot wall and a second slot wall extending from the tip of the V shape to the opening direction, and the magnet steel is embedded in the Between the first slot wall and the second slot wall, the first slot wall is arranged on one side sandwiched by the two first magnetic steel slots, and the magnetic steel includes a first slot wall perpendicular to the first slot wall. one end portion and a second end portion, the first end portion is disposed toward the V-shaped opening direction, and the second end portion is disposed toward the V-shaped tip direction;

The air slot includes a first air slot close to a corner at the first end of the magnetic steel.
The rotor according to claim 2, wherein the minimum vertical distance D1 between the slot wall of the first air slot and the first slot wall is 0.2 mm to 0.3 mm;

The vertical distance D2 from the center of the first air slot to the first end is 0.2mm to 0.3mm; the first magnetic steel slot also includes a wall connected to the first slot and facing the two first slots. A third slot wall deflected inside the included angle of the magnetic steel slot, the minimum vertical distance D3 between the slot wall of the first air slot and the third slot wall is 0.2 to 0.3 mm.
The rotor according to claim 2, wherein the air slot further comprises a second air slot, and the second air slot is close to a corner at the second end of the magnetic steel.
The rotor according to claim 4, wherein the minimum vertical distance D4 between the groove wall of the second air groove and the first groove wall is 0.2 mm to 0.4 mm; the center distance of the second air groove is 0.2 mm to 0.4 mm. The vertical distance D5 of the second end is 0.6 mm to 0.8 mm.
The rotor of claim 4, wherein the first air slot and the second air slot are elliptical.
The rotor according to claim 6, characterized in that, the length of the long axis L1 of the first air groove is 0.5mm to 0.6mm, the length of the short axis L2 is 0.3mm to 0.4mm, and the long axis and The included angle A of the first groove wall is 20° to 35°; the length of the long axis L3 of the second air groove is 0.6 mm to 0.7 mm, the length of the short axis L4 is 0.3 mm to 0.4 mm, and the length of the long axis L3 is 0.6 mm to 0.7 mm. The included angle B between the shaft and the first groove wall is 20° to 35°.
The rotor according to claim 1, wherein the magnetic steel groove group further comprises two second magnetic steel grooves distributed in a V shape and with the V-shaped tip direction facing the center of the iron core, the second magnetic steel grooves The steel slot is arranged on the side of the first magnetic steel slot away from the center of the iron core.
The rotor according to claim 1, wherein the included angle between the two first magnetic steel slots is less than 15°.
A permanent magnet motor, characterized in that the permanent magnet motor comprises the rotor according to any one of claims 1 to 9.