CN111509889A - A rotor assembly and an axial magnetic field motor - Google Patents

Abstract

The invention discloses a rotor assembly and an axial magnetic field motor, which comprise a rotor bracket, a rotor core, a high-strength hoop and magnetic steel; wherein the high strength hoop is located at an outer periphery of the rotor core, the rotor core being disposed on the rotor frame; the peripheral surface of the rotor core is provided with magnetic steel grooves extending along the radial direction of the rotor core, the magnetic steel is embedded into the magnetic steel grooves, the magnetic steel grooves are P groups, the magnetizing direction of the magnetic steel in each group of the magnetic steel grooves is the tangential direction of the rotor core, and the magnetizing direction is perpendicular to the air gap direction; and the magnetizing directions of the magnetic steels in the two adjacent groups of magnetic steel grooves are opposite. When the rotor assembly is adopted, the magnetic steel is embedded into the magnetic steel grooves on the peripheral surface of the rotor core, the magnetic steel is positioned in the axial direction, and the high-strength hoop is arranged on the peripheral surface to position the magnetic steel in the radial direction. It can be seen that the rotor assembly of the present invention has significantly improved reliability over the prior art.

Description

A rotor assembly and an axial magnetic field motor

technical field

The present invention relates to the technical field of motors, and more particularly, to a rotor assembly and an axial magnetic field motor.

Background technique

Radial field motors and axial field motors (also called disc motors) are two technical branches of the motor field. At present, most of the motors on the market are radial field motors. With the breakthrough of new materials and new processes, disc motors have begun to rise slowly. Due to higher iron core utilization, higher power density and higher torque density, disc motors are especially suitable for occasions that have strict requirements on motor volume and weight.

Please refer to FIG. 1 . FIG. 1 is a schematic diagram of an exploded structure of a rotor assembly provided in the prior art.

The rotor assembly includes: the rotor assembly is composed of a rotor back plate 100', a magnetic steel 200' and a surface iron core 300'. In this solution, the surface iron core 300' is bonded to the magnetic steel 200' and the rotor back plate 100' by glue. . On the one hand, there is a huge axial magnetic pulling force between the stator iron core and the surface iron core of the rotor. The mechanical reliability of the rotor of this structure is poor.

Therefore, how to improve the reliability of the rotor assembly has become an urgent technical problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

In view of this, the technical problem to be solved by the present invention is how to improve the reliability of the rotor assembly. Therefore, the present invention provides a rotor assembly and an axial field motor.

To achieve the above object, the present invention provides the following technical solutions:

A rotor assembly includes a rotor bracket, a rotor iron core, a high-strength hoop and a magnetic steel; wherein, the high-strength hoop is located on the outer circumference of the rotor iron core, and the rotor iron core is arranged on the rotor bracket ; A magnetic steel slot extending along the radial direction of the rotor iron core is provided on the peripheral surface of the rotor iron core, the magnetic steel is embedded in the magnetic steel slot, and the magnetic steel slot is a group P, each The magnetization direction of the magnetic steel in the magnetic steel slot of the group is the tangential direction of the rotor core, and the magnetization direction is perpendicular to the air gap direction; The magnetization direction of the magnet is opposite.

In one embodiment of the present invention, in the axial direction of the rotor iron core, the rotor iron core is provided with magnetic isolation bridges on both sides of the magnetic steel slot.

In one embodiment of the present invention, the rotor core is formed by stamping or winding.

In one embodiment of the present invention, the rotor core is processed by silicon steel sheet, amorphous alloy or magnetic powder metallurgy which is integrally molded.

In one embodiment of the present invention, the rotor iron core is fixed on the rotor support by bolts.

In one embodiment of the present invention, the rotor support is made of non-magnetic conductive steel or high-strength non-metal fiber composite material.

In one embodiment of the present invention, the rotor support is made of non-magnetic stainless steel, austenitic stainless steel, glass fiber or carbon fiber.

In one embodiment of the present invention, the rotor support and the high-strength hoop have an integral structure or a separate structure.

In one embodiment of the present invention, the high-strength hoop is processed from high-strength carbon fiber, high-strength glass fiber or titanium alloy high-strength metal.

In one of the embodiments of the present invention, an axial magnetic field motor is also disclosed, which includes the rotor assembly according to any one of the above.

It can be seen from the above technical solutions that when the rotor assembly of the present invention is used, the magnetic steel is embedded in the magnetic steel groove on the peripheral surface of the rotor core, the magnetic steel is positioned in the axial direction, and the magnetic steel is positioned on the peripheral surface by setting a high The strength hoop locates the radial direction of the magnet. It can be seen that, compared with the prior art, the rotor assembly of the present invention has significantly improved reliability.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art 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 accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a schematic diagram of an explosion structure of a rotor assembly provided by the prior art;

2 is a schematic diagram of an explosion structure of a rotor assembly provided by an embodiment of the present invention;

3 is a schematic three-dimensional structural diagram of a rotor assembly provided by an embodiment of the present invention;

FIG. 4 is a partially enlarged three-dimensional structural schematic diagram of a rotor assembly according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the principle of a rotor assembly provided by an embodiment of the present invention;

6 is a schematic diagram of the magnetic steel arrangement of a rotor assembly provided by an embodiment of the present invention;

In the figure, 100 is a rotor bracket, 200 is a high-strength hoop, 300 is a rotor iron core, 400 is a magnetic steel, 301 is a magnetic steel slot, and 302 is a magnetic isolation bridge;

100' is the rotor back plate, 200' is the magnetic steel, and 300' is the surface iron core.

Detailed ways

The core of the present invention is to provide a rotor assembly and an axial field motor to improve the reliability of the rotor assembly.

In addition, the embodiments shown below do not have any limiting effect on the content of the invention described in the claims. In addition, the whole content of the structure shown in the following embodiment is not limited to what is necessary for the solution of the invention described in the claim.

Referring to FIGS. 2 to 6 , the rotor assembly in the embodiment of the present invention includes a rotor support 100 , a rotor iron core 300 , a high-strength hoop 200 and a magnetic steel 400 ; wherein, the high-strength hoop 200 is located on the outer circumference of the rotor iron core 300 , the rotor iron core 300 is arranged on the rotor support 100; the circumferential surface of the rotor iron core 300 is provided with a magnetic steel slot 301 extending along the radial direction of the rotor iron core 300, the magnetic steel 400 is embedded in the magnetic steel slot 301, and the magnetic steel The slots 301 are group P, the magnetization direction f3 of the magnet steel 400 in each group of magnet steel slots 301 is the tangential direction of the rotor core 300, and the magnetization direction f3 is perpendicular to the air gap direction f1; the adjacent two groups of magnet steels The magnetization direction f3 of the magnetic steel 400 in the slot 301 is opposite.

When the rotor assembly of the present invention is used, the magnetic steel 400 is embedded in the magnetic steel groove 301 on the peripheral surface of the rotor core 300, the magnetic steel 400 is positioned in the axial direction, and the high-strength hoop 200 is arranged on the peripheral surface to The radial direction of the magnetic steel 400 is positioned. It can be seen that, compared with the prior art, the rotor assembly of the present invention has a stable and reliable mechanical structure of the rotor, which can not only withstand the influence of the axial magnetic pulling force, but also overcome the influence of the centrifugal force of the rotor rotation.

It should be noted that P is the number of magnetic poles of the rotor assembly, each group of magnetic steel slots 301 is composed of at least one magnetic steel 400, the magnetization direction f3 of the magnetic steel 400 in each group of magnetic steel slots 301 is the same, and the adjacent two groups The magnetization direction f3 of the magnetic steel 400 in the magnetic steel slot 301 is opposite, the magnetic fields of the adjacent two groups of the magnetic steel 400 together form one magnetic pole of the rotor assembly, and the magnetic field of the air gap pointed to by each pole is aggregated by the magnetic field of the adjacent magnetic steel 400 In other words, the air gap direction f1 is the magnetic field direction and extends in the radial direction of the rotor core 300 . The magnetization directions f3 of the magnetic steels 400 in each group of magnetic steel slots 301 are the same. Specifically, it can be understood that the magnetic steel directions f2 of all the magnetic steels 400 arranged in each group of magnetic steel slots 301 are the same.

Please refer to FIG. 5 and FIG. 6 , there are 8 groups of magnetic steel slots 301 in total in the embodiment of the present invention, each group of magnetic steel slots 301 is composed of two magnetic steels 400, and the magnetic steel 400 in each group of magnetic steel slots 301 is charged The magnetic directions f3 are the same, that is, the magnetic steel directions f2 of the two magnetic steels 400 in each group of magnetic steel slots 301 are arranged along the circumferential direction of the rotor core, N-S, or S-N arrangement. The magnetization directions f3 of the magnetic steel 400 in the adjacent two groups of magnetic steel slots 301 are opposite. In the circumferential direction of the rotor core, if the magnetic steel direction f2 of the magnetic steel 400 is N-S, the magnetization direction f3 of this group of magnetic steel slots 301 is S-N, then the magnetic steel direction f2 of the magnetic steel 400 in the adjacent group of magnetic steel slots is S-N, and the magnetizing direction f3 of this group of magnetic steel slots 301 is N-S. The magnetic fields of two adjacent groups of magnetic steels 400 together form one magnetic pole of the rotor assembly, and the magnetic fields of the magnetic steels 400 and the rotor core 300 are in the direction f1.

Since the magnetic steel 400 is embedded in the rotor iron core 300, compared with most surface-mounted magnetic steels 400, the distance between the stator iron core and the rotor iron core 300 can be greatly reduced. Therefore, the inductance of the motor (d axis inductance and q-axis inductance) can be greatly increased. When the motor performs field weakening control at high speed, when the influence of the stator resistance of the motor is ignored, the maximum ideal speed that the motor can achieve is:

In the formula, p is the number of pole pairs of the motor, ψ _f is the rotor flux linkage, L _d is the d-axis inductance of the motor, and u and i are the input voltage and input current of the motor, respectively.

It can be seen from formula (1) that under the same voltage, when the d-axis inductance of the motor is increased, the required current can be significantly reduced, or the maximum field weakening speed that the motor can achieve can be significantly increased.

In addition, since the magnetic steel 400 is inserted into the rotor iron core 300 , and the magnetization direction f3 of the magnetic steel 400 is the tangential direction of the rotor iron core 300 . For the embedded magnet 400 arrangement, the d-axis magnetic circuit of the rotor will pass through the corresponding embedded magnet 400 , while the q-axis magnetic circuit will not pass through the magnet 400 , but all closed by the rotor core 300 . Therefore, the d-axis magnetic circuit and the q-axis magnetic circuit of the rotor are not symmetrical, and the d-axis inductance < q-axis inductance, according to the formula

Τ _em = p·[ψ _f i _q +(L _d -L _q )i _d i _q ] (2)

In the formula, p is the number of pole pairs of the motor, ψ _f is the rotor flux linkage, and i _q and i _q are the d-axis current and the q-axis current, respectively. Therefore, the reluctance torque component in the second half of the above formula (2) (the first half is the permanent magnet torque component) will be added to the torque of the motor, thereby increasing the torque density of the motor. In most axial field motors, L _d =L _q , therefore, the above-mentioned rotor assembly in the structure of the embodiment of the present invention does not generate reluctance torque.

In the embodiment of the present invention, the shape of the magnetic steel 400 is a long strip structure, but the shape of the magnetic steel 400 claimed in the present invention is not limited to the long strip structure, as long as the magnetic steel 400 can be embedded in the magnetic steel groove 301 The structures are all within the protection scope of the present invention.

In another embodiment of the present invention, in the axial direction of the rotor iron core 300 , the rotor iron core 300 is provided with magnetic isolation bridges 302 on both sides of the magnetic steel slot 301 . On the premise of satisfying the mechanical strength of the rotor core 300, the axial width of the magnetic isolation bridge should be as small as possible. The function of the magnetic isolation bridge is to prevent the magnetic steel 400 from generating magnetic flux leakage in the tangential direction of the iron core.

In one embodiment of the present invention, the rotor core 300 is formed by stamping or winding. Further, the rotor core 300 is processed by silicon steel sheet, amorphous alloy or magnetic powder metallurgy which is integrally molded.

The rotor core 300 is fixed to the rotor bracket 100 by bolts. The rotor iron core 300 is provided with fixing holes between each group of magnetic steel slots 301 , and the rotor iron core 300 is fixed on the rotor bracket 100 by installing bolts in the fixing holes.

The rotor bracket 100 is made of non-magnetic steel 400 material or high-strength non-metal fiber composite material. Among them, the non-magnetic steel 400 material is non-magnetic stainless steel or austenitic stainless steel; the high-strength non-metal fiber composite material is glass fiber or carbon fiber. The high strength is required because there is a huge axial magnetic pulling force between the stator and the rotor, and the rotor bracket 100 must have sufficient strength to bear without large axial deformation. In addition, the non-magnetic permeability of the rotor support 100 is required to prevent the magnetic steel 400 magnetized tangentially from forming magnetic flux leakage inside the rotor support 100 .

The rotor support 100 and the high-strength hoop 200 have an integral structure or a separate structure. The rotor bracket 100 and the high-strength hoop 200 are made of one material, and for details, refer to the processing material of the rotor bracket 100 ; at this time, the rotor bracket 100 and the high-strength hoop 200 have limited strength.

In order to further improve the strength of the entire rotor assembly, the rotor bracket 100 and the high-strength hoop 200 are of a separate structure, and the high-strength hoop 200 is made of high-strength carbon fiber, high-strength glass fiber or titanium alloy high-strength metal.

The present invention also discloses an axial magnetic field motor, comprising the rotor assembly as described above. Since the above-mentioned rotor assembly has the above beneficial effects, the axial magnetic field motor including the above-mentioned rotor assembly also has corresponding effects, which will not be repeated here.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A rotor assembly, comprising a rotor support, a rotor iron core, a high-strength hoop and a magnetic steel; wherein, the high-strength hoop is located on the outer circumference of the rotor iron core, and the rotor iron core is arranged On the rotor support; the circumferential surface of the rotor iron core is provided with a magnetic steel slot extending in the radial direction of the rotor iron core, the magnetic steel is embedded in the magnetic steel slot, and the magnetic steel The slots are in P groups, the magnetization direction of the magnetic steel in each group of the magnetic steel slots is the tangential direction of the rotor core, and the magnetization direction is perpendicular to the air gap direction; The magnetization directions of the magnetic steel in the magnetic steel slot are opposite. 2 . The rotor assembly according to claim 1 , wherein in the axial direction of the rotor iron core, the rotor iron core is provided with magnetic isolation bridges on both sides of the magnetic steel slot. 3 . 3 . The rotor assembly of claim 2 , wherein the rotor core is formed by stamping or winding. 4 . 4 . The rotor assembly according to claim 3 , wherein the rotor core is processed by silicon steel sheet, amorphous alloy or integrally molded magnetic powder metallurgy. 5 . 5 . The rotor assembly of claim 1 , wherein the rotor core is fixed on the rotor bracket by bolts. 6 . 6 . The rotor assembly of claim 1 , wherein the rotor support is made of non-magnetic conductive steel or high-strength non-metal fiber composite material. 7 . 7 . The rotor assembly of claim 6 , wherein the rotor support is made of non-magnetic stainless steel, austenitic stainless steel, glass fiber or carbon fiber. 8 . 8 . The rotor assembly according to claim 6 , wherein the rotor support and the high-strength hoop have an integral structure or a separate structure. 9 . 9 . The rotor assembly of claim 8 , wherein the high-strength hoop is made of high-strength carbon fiber, high-strength glass fiber or titanium alloy high-strength metal. 10 . 10. An axial field motor, characterized in that it comprises the rotor assembly according to any one of claims 1 to 10.

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