阅读说明：本技术 带有低磁导率磁桥的永磁电机转子 (Permanent magnet motor rotor with low-permeability magnetic bridge ) 是由 林德芳 于 2019-11-22 设计创作，主要内容包括：一种带有低磁导率磁桥的永磁电机转子,涉及电机技术领域,所解决的是现有转子综合性能与机械强度不能兼具的技术问题。该转子包括转子铁芯,及安装在转子铁芯上的围绕转子铁芯的轴心对称布设的多个永磁单元,所述永磁单元包含有至少一根磁钢,所述转子铁芯上设有多个T型磁桥,并且每两个永磁单元之间都设置有一个T型磁桥,所述T型磁桥的磁导率低于转子铁芯的磁导率,T型磁桥的横条段的内侧面抵住两侧相邻的磁钢的端部,并且T型磁桥的竖条段抵住两侧相邻的磁钢的端部。本发明提供的转子,特别适合电动汽车使用。(A permanent magnet motor rotor with a low-permeability magnetic bridge relates to the technical field of motors and solves the technical problem that the comprehensive performance and the mechanical strength of the existing rotor cannot be combined. This rotor includes rotor core, and installs a plurality of permanent magnetism units of laying around rotor core's axle center symmetry on rotor core, permanent magnetism unit includes an at least magnet steel, be equipped with a plurality of T type magnetic bridges on the rotor core to all be provided with a T type magnetic bridge between per two permanent magnetism units, the magnetic conductivity of T type magnetic bridge is less than rotor core's magnetic conductivity, and the medial surface of the horizontal strip section of T type magnetic bridge supports the tip of the adjacent magnet steel in both sides, and the perpendicular strip section of T type magnetic bridge supports the tip of the adjacent magnet steel in both sides. The rotor provided by the invention is particularly suitable for electric automobiles.)

1. The utility model provides a permanent-magnet machine rotor with low magnetic permeability magnetic bridge, includes rotor core, and installs a plurality of permanent magnetism units of laying around rotor core's axle center symmetry on rotor core, permanent magnetism unit includes an at least magnet steel, its characterized in that:

the rotor core is provided with a plurality of T-shaped magnetic bridges, a T-shaped magnetic bridge is arranged between every two permanent magnet units, the magnetic conductivity of the T-shaped magnetic bridge is lower than that of the rotor core, the inner side face of the transverse strip section of the T-shaped magnetic bridge supports the end portions of the adjacent magnetic steels on the two sides, and the vertical strip section of the T-shaped magnetic bridge supports the end portions of the adjacent magnetic steels on the two sides.

2. The rotor of a permanent magnet electric machine with low permeability bridges of claim 1, wherein: the permanent magnet unit is a linear magnetic steel.

3. The rotor of a permanent magnet electric machine with low permeability bridges of claim 2, wherein: the radial section of the vertical bar section of the T-shaped magnetic bridge is in a trapezoid shape gradually narrowing from inside to outside.

4. The rotor of a permanent magnet electric machine with low permeability bridges of claim 1, wherein: the permanent magnet unit consists of an arc-shaped magnetic steel with an inward arc top.

5. The rotor of a permanent magnet electric machine with low permeability bridges of claim 1, wherein: the permanent magnet unit consists of two linear magnetic steels, and the two magnetic steels in the permanent magnet unit are arranged into a V shape with inward tips.

6. The rotor of a permanent magnet electric machine with low permeability bridges of claim 5, wherein: the rotor core is provided with a plurality of oval pole shoe center holes, each pole shoe center hole corresponds to each permanent magnet unit one by one, and each pole shoe center hole is arranged between two pieces of magnetic steel of the corresponding permanent magnet unit.

7. The rotor of a permanent magnet electric machine with low permeability bridges of claim 1, wherein: the permanent magnet unit consists of three linear magnetic steels, and three magnetic steels in the permanent magnet unit are arranged into a U shape with an outward opening.

Technical Field

The invention relates to a motor technology, in particular to a technology of a permanent magnet motor rotor with a low-permeability magnetic bridge.

Background

Electric automobiles generally adopt built-in permanent magnet synchronous motors as power sources, and the existing built-in permanent magnet synchronous motors have the defects of low power density, large torque fluctuation, low overload capacity, poor reliability and the like, so that the power output requirements of the electric automobiles are difficult to meet.

The effective way for improving the power density and the torque density is to improve the air gap magnetic flux and the air gap magnetic density, and the existing built-in permanent magnet synchronous motor has two ways of improving the air gap magnetic density: 1) air permanent magnet grooves (namely nonmagnetic flux barriers) are arranged at two ends of the built-in magnetic steel, and can play a role in magnetic isolation, so that the air gap flux density is improved; 2) a magnetic isolation magnetic bridge is arranged at the crossed axis (inter-pole center line and q axis) of the rotor core, so that the air gap flux density is improved.

However, the magnetic isolation magnetic bridge of the existing built-in permanent magnet synchronous motor is substantially formed by the rotor core positioned at the quadrature axis part, so that the magnetic isolation magnetic bridge also has high magnetic conductivity and has the defect of large magnetic leakage, and the magnetic isolation magnetic bridge is positioned at the outer edge part of the rotor core, so that the thickness of the magnetic isolation magnetic bridge is too narrow, the mechanical strength is poor, and the manufacturing process and the manufacturing cost of the motor are high; because the maximum stress of the rotor is inversely proportional to the thickness of the magnetic bridge and directly proportional to the square of the rotating speed, the rotor still has the hidden trouble of plastic deformation in a high-speed state, and the high-speed operation safety of the motor is poor.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a permanent magnet motor rotor with a low-permeability magnetic bridge, which has high air gap flux density and high mechanical strength.

In order to solve the technical problem, the invention provides a permanent magnet motor rotor with a low-permeability magnetic bridge, which comprises a rotor core and a plurality of permanent magnet units which are arranged on the rotor core and symmetrically distributed around the axis of the rotor core, wherein the permanent magnet units comprise at least one piece of magnetic steel, and the permanent magnet motor rotor is characterized in that:

the rotor core is provided with a plurality of T-shaped magnetic bridges, a T-shaped magnetic bridge is arranged between every two permanent magnet units, the magnetic conductivity of the T-shaped magnetic bridge is lower than that of the rotor core, the inner side face of the transverse strip section of the T-shaped magnetic bridge supports the end portions of the adjacent magnetic steels on the two sides, and the vertical strip section of the T-shaped magnetic bridge supports the end portions of the adjacent magnetic steels on the two sides.

Furthermore, the permanent magnet unit is a linear magnetic steel.

Furthermore, the radial section of the vertical bar section of the T-shaped magnetic bridge is in a trapezoid shape which is gradually narrowed from inside to outside.

Furthermore, the permanent magnet unit is composed of an arc-shaped magnetic steel with an inward arc top.

Furthermore, the permanent magnet unit is composed of two linear magnetic steels, and two magnetic steels in the permanent magnet unit are arranged into a V shape with inward tips.

Furthermore, a plurality of oval pole shoe center holes are formed in the rotor iron core, each pole shoe center hole corresponds to each permanent magnet unit one by one, and each pole shoe center hole is arranged between two pieces of magnetic steel of the corresponding permanent magnet unit.

Furthermore, the permanent magnet unit is composed of three linear magnetic steels, and three magnetic steels in the permanent magnet unit are arranged into a U shape with an outward opening.

According to the permanent magnet motor rotor with the low-permeability magnetic bridges, the T-shaped magnetic bridges with low permeability are arranged between the adjacent permanent magnet units, magnetic leakage can be reduced, air gap flux density is improved, and therefore power density, torque density and overload capacity of the motor are improved.

Drawings

Figure 1 is a radial cross-sectional view of a permanent magnet electric machine rotor with low permeability bridges according to a first embodiment of the present invention;

FIG. 2 is a radial cross-sectional view of a permanent magnet electric machine rotor with low permeability magnetic bridges in accordance with a second embodiment of the present invention;

FIG. 3 is a radial cross-sectional view of a permanent magnet electric machine rotor with low permeability magnetic bridges of a third embodiment of the present invention;

FIG. 4 is a radial cross-sectional view of a rotor of a permanent magnet electric machine with low permeability bridges of a fourth embodiment of the present invention;

figure 5 is a radial cross-sectional view of a rotor of a permanent magnet electric machine with low permeability bridges according to a fifth embodiment of the invention;

fig. 6 is a radial cross-sectional view of a rotor of a permanent magnet electric machine with low permeability bridges according to a sixth embodiment of the invention.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the following description of the drawings, but the embodiments are not intended to limit the present invention, and all similar structures and similar variations using the present invention shall be included in the scope of the present invention, and the pause numbers in the present invention shall have a relation of the same.

As shown in fig. 1, a permanent magnet motor rotor with a low-permeability magnetic bridge according to a first embodiment of the present invention includes a rotor core 11, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around an axis of the rotor core, where the permanent magnet units are linear magnetic steels 12, and is characterized in that:

the rotor core 11 is provided with a plurality of T-shaped magnetic bridges 13, and a T-shaped magnetic bridge 13 is arranged between every two permanent magnet units, the T-shaped magnetic bridges 13 are made of a material with low magnetic conductivity and high magnetic resistance (such as stainless steel), the magnetic conductivity of the T-shaped magnetic bridges 13 is lower than that of the rotor core 11 (made of silicon steel sheets), the inner side surfaces (facing the rotor core axis side is the inner side) of the transverse bar sections 131 (the upper transverse part of the T-shaped magnetic bridges) of the T-shaped magnetic bridges support the end parts of the magnetic steels 12 adjacent to both sides, and the vertical bar sections 132 (the vertical parts of the T-shaped magnetic bridges support the end parts of the magnetic steels 12 adjacent to both sides.

In the first embodiment of the invention, the T-shaped magnetic bridge with low magnetic permeability can effectively limit magnetic leakage and improve air gap magnetic density, and because the T-shaped magnetic bridge has small magnetic leakage, an air permanent magnetic slot is not required to be arranged at the end part of the magnetic steel (the air permanent magnetic slot is arranged and is generally adopted in the existing built-in rotor), the magnetic steel is directly connected with the T-shaped magnetic bridge, the magnetization area can be increased, the air gap magnetic density is improved, and the power density and the torque density of the motor are effectively improved; and the T-shaped magnetic bridge with low magnetic conductivity can also meet the requirement of small no-load magnetic leakage coefficient, so that the power density and the torque density of the motor can be improved, and meanwhile, the T-shaped magnetic bridge has enough mechanical strength, and the high-speed running safety and reliability of the motor are ensured.

The comparison result of the rotor with the rated output power of 50KW adopting the technical scheme of the first embodiment of the invention and the existing built-in linear permanent magnet synchronous motor rotor with the same specification is as follows:

the rated current of the first embodiment of the invention is 80A, the efficiency is 96.6 percent, the rated power is 55KW, the rated torque is 146Nm, and the maximum torque is 314 Nm;

the rated current of the rotor of the existing built-in linear permanent magnet synchronous motor is 82.5A, the efficiency is 94.5 percent, the rated power is 50KW, the rated torque is 132.6Nm, and the maximum torque is 285 Nm;

it can be seen that the parameters of the first embodiment of the present invention are improved compared to the existing built-in-line type permanent magnet synchronous motor rotor.

As shown in fig. 2, the structure of the second embodiment of the present invention is similar to that of the first embodiment, the second embodiment also includes a rotor core 21, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around the axis of the rotor core, the permanent magnet units are also linear magnetic steels 22, a plurality of T-shaped magnetic bridges 23 are also arranged on the rotor core 21, and a T-shaped magnetic bridge 23 is arranged between every two permanent magnet units;

the second embodiment of the present invention differs from the first embodiment in that: in the second embodiment, the radial cross section of the vertical bar section 232 of the T-shaped magnetic bridge 23 is a trapezoid gradually narrowing from inside to outside, so that the requirement of small no-load leakage coefficient can be met, the power density and the torque density of the motor are improved, and meanwhile, the mechanical strength is sufficient, and the high-speed operation safety and reliability of the motor are ensured.

As shown in fig. 3, the structure of the third embodiment of the present invention is similar to that of the first embodiment, and the third embodiment also includes a rotor core 31, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around the axis of the rotor core, wherein a plurality of T-shaped magnetic bridges 33 are also arranged on the rotor core 31, and one T-shaped magnetic bridge 33 is arranged between every two permanent magnet units;

the third embodiment of the present invention differs from the first embodiment in that: the permanent magnet unit in the third embodiment is composed of two linear magnetic steels 32, and the two magnetic steels 32 in the permanent magnet unit are arranged into a V shape with the tips facing inwards (the side facing the axis of the rotor core is the inner side), the magnetic steels are directly connected with the high-reluctance T-shaped magnetic bridge, which is equivalent to that the equivalent air gaps at the two ends of the excircle of the rotor pole shoe are increased, the reluctance is increased, the magnetic line of force passing capacity is weakened, the pole arc coefficient is reduced, the air gap magnetic density at the two ends is reduced, the air gap magnetic field waveform of the motor is improved, the torque fluctuation and the mechanical vibration caused by the tooth space are reduced, and the power density and; and the T-shaped magnetic bridge with low magnetic conductivity can also meet the requirement of small no-load magnetic leakage coefficient, so that the power density and the torque density of the motor can be improved, and meanwhile, the T-shaped magnetic bridge has enough mechanical strength, and the high-speed running safety and reliability of the motor are ensured.

The comparison result between the rotor with the rated output power of 50KW adopting the technical scheme of the third embodiment of the invention and the existing built-in V-shaped permanent magnet synchronous motor rotor with the same specification is as follows:

the rated current of the third embodiment of the invention is 78.6A, the efficiency is 97.4 percent, the rated power is 55KW, and the rated torque is 146 Nm;

the rated current of the existing built-in V-shaped permanent magnet synchronous motor rotor is 79.1A, the efficiency is 95.6 percent, the rated power is 50KW, and the rated torque is 132.6 Nm;

it can be seen that the parameters of the third embodiment of the present invention are improved compared to the existing built-in V-shaped permanent magnet synchronous motor rotor.

As shown in fig. 4, the structure of the fourth embodiment of the present invention is similar to that of the first embodiment, and the fourth embodiment also includes a rotor core 41, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around the axis of the rotor core, a plurality of T-shaped magnetic bridges 43 are also arranged on the rotor core 41, and one T-shaped magnetic bridge 43 is arranged between every two permanent magnet units;

the fourth embodiment of the present invention differs from the first embodiment in that: the permanent magnet unit in the fourth embodiment is composed of an arc-shaped magnetic steel 42 with an inward arc top, and the arc-shaped magnetic steel 42 can increase the magnetization area and further improve the air gap flux density compared with the first embodiment.

As shown in fig. 5, the structure of the fifth embodiment of the present invention is similar to that of the third embodiment, the fifth embodiment also includes a rotor core 51, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around the axis of the rotor core, the permanent magnet unit also includes two linear magnetic steels 52, and the two magnetic steels 52 in the permanent magnet unit are also arranged in a V shape with their tips facing inward (the side facing the axis of the rotor core is the inner side), the rotor core 51 is also provided with a plurality of T-shaped magnetic bridges 53, and a T-shaped magnetic bridge 53 is arranged between each two permanent magnet units;

the fifth embodiment of the present invention is different from the third embodiment in that: the rotor core 51 in the fifth embodiment is provided with a plurality of elliptical pole shoe center holes 54, each pole shoe center hole 54 corresponds to each permanent magnet unit one by one, each pole shoe center hole 54 is arranged between two magnetic steels 52 of the corresponding permanent magnet unit, and the pole shoe center holes 54 can inhibit static and dynamic armature reaction demagnetization, so that the stable operation of high efficiency, high power density, low-speed constant torque and high-speed constant power speed expansion can be well obtained.

In the fifth embodiment of the present invention, the inner side surface (the side facing the rotor core axis is the inner side) of the horizontal bar 531 (the upper horizontal part of the T-shaped magnetic bridge) and the vertical bar 532 (the vertical part of the T-shaped magnetic bridge) of the T-shaped magnetic bridge also respectively abut against the end parts of the adjacent magnetic steels 52 at both sides, and the radial cross section of the vertical bar 532 of the T-shaped magnetic bridge 53 is a trapezoid gradually narrowing from inside to outside, so that the requirement of small no-load leakage coefficient can be satisfied, thereby improving the power density and torque density of the motor, and simultaneously having sufficient mechanical strength, and ensuring the safety and reliability of the high-speed operation of the motor.

As shown in fig. 6, the structure of the sixth embodiment of the present invention is similar to that of the first embodiment, and the sixth embodiment also includes a rotor core 61, and a plurality of permanent magnet units mounted on the rotor core and symmetrically arranged around the axis of the rotor core, where a plurality of T-shaped magnetic bridges 63 are also disposed on the rotor core 61, and a T-shaped magnetic bridge 63 is disposed between every two permanent magnet units;

the sixth embodiment of the present invention is different from the first embodiment in that: the permanent magnet unit in the sixth embodiment is composed of three linear magnetic steels 62, and the three magnetic steels 62 in the permanent magnet unit are arranged into a U shape with an outward opening (the side facing the axis of the rotor core is the inner side), and the total magnetic flux provided by the permanent magnet unit to an external magnetic circuit can be increased by the U-shaped magnetic steel group, so that the power density and the torque density of the motor can be doubly and effectively improved.