CN111600407A - Permanent magnet motor rotor - Google Patents

Abstract

The present invention is a permanent magnet motor rotor suitable for an aircraft electric propulsion system. The rotor includes a permanent magnet, a rotor yoke, a rotor bracket, a squirrel-cage damping winding, a tuyere and the like. The permanent magnet is installed on the rotor yoke, the rotor yoke is installed on the rotor bracket, the squirrel-cage damping winding is installed on the surface of the rotor, which acts as the installation tool of the permanent magnet, and can also be used to fix the permanent magnet. The damping winding end plate acts as a balance end plate. Correction of rotor dynamic balance. The rotor is provided with an axial air duct, and the air duct is arranged on the rotor yoke or the rotor support, and the air duct can also be formed by using a hollow damping winding. The air inlet of the air duct is not treated, and the air outlet is provided with an air nozzle. When the two ends of the air duct rotate, a pressure difference can be generated, resulting in a self-suction air effect. The rotor design scheme has a simple structure and can improve the cooling effect of the permanent magnet motor rotor without additional cooling equipment, which can enhance the operational reliability of the permanent magnet motor for aircraft electric propulsion, and can also be applied to other fields such as new energy vehicles and household appliances.

Description

A permanent magnet motor rotor

technical field

The invention relates to a lightweight and low-loss permanent magnet motor rotor, which belongs to the technical field of motors.

Background technique

Permanent magnet motors have the characteristics of high torque density and high efficiency, and have been widely used in new energy vehicles, household appliances, aerospace and other fields. At present, aircraft electrification is an important direction for the development of aviation technology, and advanced concepts and technologies such as multi-electric/all-electric aircraft and electric propulsion aircraft have been born. Sex and other aspects must meet higher requirements than the current level. It is with its advantages that permanent magnet motors have become strong competitors in the field of aviation applications.

Compared with the electric excitation motor, the excitation potential of the permanent magnet motor is derived from the permanent magnet, and the permanent magnet can permanently provide a certain strength of the magnetic field after being magnetized. Thanks to the development of high-performance rare earth permanent magnet materials, the current permanent magnets can provide a relatively strong magnetic field with a smaller volume, bringing the advantages of high power density and high torque density to permanent magnet motors. At the same time, the permanent magnet motor has no excitation loss and is more efficient.

However, rare earth permanent magnets generally have electrical conductivity. When the magnetic flux passing through the permanent magnet changes, an electric potential will be induced in the permanent magnet, resulting in an eddy current, and the thermal effect of the eddy current will cause the permanent magnet to heat up. The permanent magnet is more sensitive to temperature. The increase of temperature will lead to the decline of the magnetic performance of the permanent magnet. When the temperature rises to the temperature resistance limit of the permanent magnet, the permanent magnet will be permanently demagnetized. During the operation of the permanent magnet motor system, the armature current often contains certain harmonic components, and the harmonic magnetic field speed generated by these harmonic components is not synchronous, which will lead to eddy current loss on the permanent magnet. Generally speaking, the loss of the permanent magnet motor is mainly concentrated on the stator. The permanent magnet motor stator is designed with a cooling system, while the permanent magnet motor rotor loss is relatively limited. Setting a cooling system on the rotor will lead to a complicated structure and increase the weight. Therefore, usually Not having a dedicated cooling system on the rotor would allow heat to build up on the permanent magnets, causing the permanent magnets to rise in temperature and increasing the risk of permanent magnet demagnetization.

In addition, the effective parts of the permanent magnet motor rotor are permanent magnets and iron cores. In order to reduce the weight of the permanent magnet motor, it is necessary to properly design the permanent magnet motor rotor to maximize the performance of materials and achieve the purpose of light weight.

SUMMARY OF THE INVENTION

In view of the above technical problems, the present invention aims to provide a novel permanent magnet motor rotor structure, which has the characteristics of light weight, can reduce the rotor loss caused by the stator harmonic magnetic field, and can perform air suction cooling through its own structure.

In order to realize the above-mentioned technical purpose, the technical scheme of the present invention is:

A lightweight and low-loss permanent magnet motor rotor, the permanent magnet motor rotor includes a permanent magnet, a rotor yoke, a rotor bracket, a damping winding and a tuyere; the damping winding is a squirrel-cage damping winding, which is installed on the surface of the rotor; The magnet is installed on the rotor yoke, an axial air duct is arranged on the rotor along the axial direction, end plates are arranged at both ends of the rotor yoke, and an air nozzle is arranged on the end plate at one end.

Further, the permanent magnets are surface-mounted on the rotor yoke. If the permanent magnets are placed in a Halbach array, the rotor yoke is cancelled, and the permanent magnets are directly mounted on the rotor support.

Further, the squirrel-cage damping winding is composed of damping bars and end plates on both sides, and both the damping bars and the end plates are made of conductors.

Further, the end plate is used as a rotor balance end plate for dynamic balance correction of the rotor; when the rotor is assembled, the damping winding is used as a permanent magnet installation tool, and the damping strip cooperates with the positioning groove provided on the surface of the permanent magnet; the damping winding At the same time, it acts as a fixed permanent magnet. When the motor speed is high, the strength of the rotor can be improved through the sheath.

Further, the position of the axial air duct is installed in the rotor yoke or on the rotor support, or a hollow damping strip is used as the axial air duct; if the axial air duct is set in the rotor yoke, the axial air duct is set according to the direction of the magnetic force line. road.

Further, one side of the air duct is not treated, and the other side is provided with a tuyere; when the rotor rotates, the airflow speed on one side of the tuyere is greater than the other side, resulting in a pressure difference between the two ends of the air duct, and the rotor self-suction is realized.

As a preference, the rotor yoke is formed by laminating laminations, or is a whole piece of magnetically conductive material; the rotor yoke is installed on the rotor bracket through interference fit, and torque is transmitted between the rotor yoke and the rotor bracket through a key slot.

As a preferred option, the rotor bracket is made of titanium alloy or aluminum alloy, and has a spoke-type structure or a hollow cup structure, and the rotor bracket is sleeved on the rotor shaft.

After adopting the above scheme, the present invention has the following advantages compared with the existing permanent magnet rotor structure:

(1) The rotor structure pursues lightweight design, and the weight is lighter under the same electromagnetic parameters;

(2) It can effectively suppress the rotor loss caused by the stator harmonic magnetic field, minimize the heat generation of the rotor, improve the motor efficiency, and reduce the risk of permanent magnet demagnetization;

(3) The self-aspirating structure realizes cooling of the rotor, further reduces the risk of permanent magnet demagnetization, and improves the reliability of the motor. Since the rotor does not require additional cooling structure, it also helps to realize the lightweight design of the rotor.

Description of drawings

Figure 1 is the structure diagram of the permanent magnet motor rotor, (a): rotor yoke axial air duct, (b): hollow damping strip axial air duct;

Figure 2 is a cross-sectional view of a permanent magnet motor rotor, (a): rotor yoke axial air duct, (b): hollow damping strip axial air duct;

Figure 3 is a schematic diagram of the setting position of the axial air duct, (a): the axial air duct of the rotor yoke, (b): the axial air duct of the hollow damping strip;

Figure 4 is the structure diagram of squirrel-cage damping winding, (a): ordinary damping winding, (b): hollow damping winding;

Figure 5 is a schematic diagram of the damping winding used as an installation tool, (a): ordinary damping winding, (b): hollow damping winding;

Figure 6 is a schematic diagram of the axial air duct self-suction;

In the figure, 1-permanent magnet, 2-damping strip, 3-rotor bracket, 4-end plate, 5-air nozzle, 6-rotor yoke, 7-axial air duct, 8-rotating shaft.

Detailed ways

The technical solutions of the invention will be described in detail below with reference to the accompanying drawings.

The invention provides a lightweight and low-loss permanent magnet motor rotor. The permanent magnet motor rotor includes a permanent magnet, a rotor yoke, a rotor bracket, a damping winding and a tuyere; the damping winding is a squirrel-cage damping winding, which is installed on the surface of the rotor The permanent magnet is installed on the rotor yoke, an axial air duct is arranged on the rotor along the axial direction, end plates are arranged at both ends of the rotor yoke, and an air nozzle is arranged on the end plate at one end.

Further, the permanent magnets are surface-mounted on the rotor yoke. If the permanent magnets are placed in a Halbach array, the rotor yoke is cancelled, and the permanent magnets are directly mounted on the rotor support.

Further, the squirrel-cage damping winding is composed of damping bars and end plates on both sides, and both the damping bars and the end plates are made of conductors.

Further, the end plate is used as a rotor balance end plate for dynamic balance correction of the rotor; when the rotor is assembled, the damping winding is used as a permanent magnet installation tool, and the damping strip cooperates with the positioning groove provided on the surface of the permanent magnet; the damping winding At the same time, it acts as a fixed permanent magnet. When the motor speed is high, the strength of the rotor can be improved through the sheath.

Further, the position of the axial air duct is installed in the rotor yoke or on the rotor support, or a hollow damping strip is used as the axial air duct; if the axial air duct is set in the rotor yoke, the axial air duct is set according to the direction of the magnetic force line. road.

Further, one side of the air duct is not treated, and the other side is provided with a tuyere; when the rotor rotates, the airflow speed on one side of the tuyere is greater than the other side, resulting in a pressure difference between the two ends of the air duct, and the rotor self-suction is realized.

As a preference, the rotor yoke is formed by laminating laminations, or is a whole piece of magnetically conductive material; the rotor yoke is installed on the rotor bracket through interference fit, and torque is transmitted between the rotor yoke and the rotor bracket through a key slot.

As a preferred option, the rotor bracket is made of titanium alloy or aluminum alloy, and has a spoke-type structure or a hollow cup structure, and the rotor bracket is sleeved on the rotor shaft.

As shown in FIG. 1 , the present invention provides a lightweight and high-efficiency permanent magnet motor rotor. The permanent magnet motor rotor includes permanent magnets 1 , squirrel-cage damping windings, rotor brackets 3 , air nozzles 5 , rotor yokes 6 , and the like. The squirrel-cage damping winding is composed of damping bars 2 and end plates 4 on both sides.

Specifically, as shown in FIG. 2 , in the permanent magnet motor rotor provided by the present invention, the permanent magnet 1 is installed on the rotor yoke 6 , the rotor yoke 6 is sleeved on the rotor bracket 3 , and the rotor bracket 3 is installed on the rotating shaft 8 . The damping bar 2 is embedded on the surface of the permanent magnet 1, and the damping bar 2 is connected with the end plates 4 on both sides to form a squirrel-cage damping winding. The axial air duct 7 is arranged on the rotor yoke 6, and the air nozzle 5 is arranged on one side of the air duct 7, as shown in Fig. 1(a). The axial air duct 7 can also be formed by the hollow damping strip 2, as shown in Fig. 1(b).

As shown in FIG. 3 , the direction of the magnetic field lines of the permanent magnet 1 needs to be considered when setting the rotor yoke axial air duct 7 , and the air duct 7 needs to be arranged directly below each pole.

Figure 4 is a structural diagram of a squirrel-cage damping winding. The damping winding includes a damping bar 2 and end plates 4 on both sides. The connection method can be welding or crimping.

5 is a schematic diagram of the damping winding being used as a permanent magnet 1 installation tool. First, the rotor yoke 6 is installed on the rotor support 3, and then the damping bar 2 is installed on one side end plate 4, and then installed on the rotor yoke 6. On the whole combined with the rotor bracket 3 , the shape of the permanent magnet 1 and the damping bar 2 cooperate with each other. At this time, the permanent magnet 1 can be directly inserted for assembly, and finally the end plate 4 on the other side is installed.

Figure 6 is a schematic diagram of the rotor self-suction. When the rotor rotates, the air nozzle 5 is arranged on one side of the axial air duct 7, and the air flow rate on this side will be greater than the other side, resulting in a pressure difference between the two ends of the axial air duct 7. So as to achieve the effect of self-aspirating.

The above are only preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application. Inside.

Claims (8)

1. A permanent magnet motor rotor characterized in that: the permanent magnet motor rotor comprises a permanent magnet, a rotor yoke, a rotor bracket, a damping winding and a tuyere; the damping winding is a squirrel-cage damping winding and is arranged on the surface of the rotor; the permanent magnet is arranged on the rotor yoke, an axial air duct is arranged on the rotor along the axial direction, end plates are arranged at two ends of the rotor yoke, and an air nozzle is arranged on the end plate at one end.

2. The permanent magnet motor rotor of claim 1, wherein: the permanent magnet is arranged on the rotor yoke in a surface-mounted mode, and if the permanent magnet is arranged in a Halbach array mode, the rotor yoke is omitted, and the permanent magnet is directly arranged on the rotor support.

3. The permanent magnet motor rotor of claim 1, wherein:

the squirrel-cage damping winding is composed of damping bars and end plates on two sides, wherein the damping bars and the end plates are made of conductors.

4. The permanent magnet motor rotor of claim 1, wherein:

the end plate is used as a rotor balance end plate and used for correcting the dynamic balance of the rotor, when the rotor is assembled, the damping winding is used as an installation tool of the permanent magnet, and the damping strip is matched with a positioning groove arranged on the surface of the permanent magnet; the damping winding plays the effect of fixed permanent magnet simultaneously, and the accessible sheath improves rotor intensity when motor speed is higher.

5. The permanent magnet motor rotor of claim 1, wherein:

the axial air duct is arranged in the rotor yoke or on the rotor bracket, or a hollow damping strip is adopted as the axial air duct; if the rotor yoke is provided with the axial air duct, the axial air duct is arranged according to the trend of the magnetic lines of force.

6. The permanent magnet electric machine rotor of claim 5, characterized in that:

one side of the air duct is not processed, and the other side of the air duct is provided with an air nozzle; when the rotor rotates, the air speed of one side of the air nozzle is higher than that of the other side of the air nozzle, so that the pressure difference between two ends of the air duct is caused, and the rotor can automatically suck air.

7. The permanent magnet electric machine rotor according to any of claims 1 to 6, characterized in that: the rotor yoke is formed by laminating laminations or is a whole piece of magnetic conductive material; the rotor yoke is arranged on the rotor support in an interference fit mode, and torque is transmitted between the rotor yoke and the rotor support through a key groove.

8. The permanent magnet electric machine rotor of claim 7, wherein: the rotor support is made of titanium alloy or aluminum alloy and is of a spoke type structure or a hollow cup structure, and the rotor support is sleeved on the rotor shaft.

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