Asymmetric large and small magnetic pole structure of surface-mounted permanent magnet motor rotor
Technical Field
The utility model relates to the technical field of motors, in particular to a surface-mounted permanent magnet motor rotor asymmetric magnetic pole structure.
Background
The existing permanent magnet motor has the advantages of high power factor, high efficiency, small current and the like, and is widely applied to various industries, thereby realizing good energy-saving effect. However, the permanent magnet motor has cogging torque, which often causes motor torque pulsation and also causes adverse effects such as vibration and noise. In some occasions with special requirements on noise and vibration, certain measures need to be taken to eliminate or weaken the cogging torque. The traditional method comprises the following steps: 1. by adopting the stator chute, the cogging torque can be effectively reduced, but after the stator chute is adopted, each stator slot is inclined at a certain angle, and each stator slot is not aligned, so that automatic wire embedding equipment cannot be used for large-batch and automatic production; 2. the cogging torque is reduced by adopting a mode of a stator straight slot and a rotor oblique pole, each piece of magnetic steel is bonded in a segmented mode, high requirements are provided for assembly among the magnetic steels, and phase precision of different magnetic poles after the oblique pole is also high, so that the assembly difficulty is high, the manufacturing precision is not high, and the cogging torque reduction effect is not obvious if the design and the process are not good.
SUMMERY OF THE UTILITY MODEL
In view of this, the present invention provides an asymmetric magnetic pole structure of a surface-mounted permanent magnet motor rotor, which aims to solve one of the problems in the background art and reduce cogging torque.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a surface-mounted permanent magnet motor rotor asymmetric large and small magnetic pole structure comprises: rotor core, rotor core's center has the shaft hole, rotor core's surface is provided with first magnet steel and second magnet steel along its axial, first magnet steel is equipped with one, the second magnet steel is equipped with a plurality ofly, first magnet steel and a plurality of second magnet steel interval set up in rotor core's surface, and the interval between first magnet steel and the second magnet steel equals the interval between two adjacent first magnet steels, and wherein, the arc length of first magnet steel is greater than the arc length of second magnet steel.
Further, the length of the first magnetic steel and the length of the second magnetic steel are equal to the length of the rotor core.
Further, first magnet steel includes a plurality of first magnetic poles, and a plurality of first magnetic poles are followed rotor core's axial splices in proper order forms first magnet steel.
Further, the second magnetic steel comprises a plurality of second magnetic poles, and the second magnetic poles are sequentially spliced along the axial direction of the rotor core to form the second magnetic steel.
Further, the length of the first magnetic pole is equal to the length of the second magnetic pole.
Furthermore, through holes are formed in the center positions of the first magnetic pole and the second magnetic pole, threaded holes are formed in the positions, corresponding to the first magnetic pole and the second magnetic pole, of the outer surface of the rotor core, and the first magnetic pole and the second magnetic pole are connected with the rotor core through screws respectively.
Furthermore, the surface-mounted permanent magnet motor rotor asymmetric magnetic pole structure further comprises a rotating shaft, and the rotating shaft penetrates through the shaft hole and is fixedly connected with the rotor iron core.
Compared with the prior art, the surface-mounted permanent magnet motor rotor asymmetric magnetic pole structure provided by the utility model has the following beneficial effects:
1. the utility model relates to a surface-mounted permanent magnet motor rotor asymmetric magnetic pole structure, which is characterized in that one first magnetic steel is arranged, a plurality of second magnetic steels are arranged, the arc length of the first magnetic steel is greater than that of the second magnetic steel, and the included angles of gaps between every two adjacent magnetic steels are equal.
2. The utility model is suitable for the permanent magnet motor with the stator straight slot and the rotor magnetic steel surface-mounted type, the surfaces of the first magnetic pole and the second magnetic pole are both provided with the through holes, so that the first magnetic pole and the second magnetic pole can be fixed on the surface of the rotor iron core through screws, the first magnetic pole and the second magnetic pole can be fixed on the rotor without using adhesives, the assembly of the first magnetic pole and the second magnetic pole can be rapidly and conveniently completed, and the assembly efficiency of products is improved.
3. The utility model solves the problem that the traditional permanent magnet motor eliminates or weakens the cogging torque, if a stator chute mode is adopted, each stator slot is inclined by a certain angle, and each stator slot is not aligned, so that automatic line inserting equipment cannot be used for large-batch and automatic production; if a rotor oblique pole mode is adopted, the problems that each magnetic pole is bonded in a segmented mode, the assembly precision requirement between the same magnetic pole and different magnetic poles is high, the assembly difficulty is high, the manufacturing precision is low and the like exist.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an asymmetric magnetic pole structure of a surface-mounted permanent magnet motor rotor according to the present invention;
FIG. 2 is a left side view of an asymmetric magnetic pole structure of a surface-mounted permanent magnet motor rotor according to the present invention;
FIG. 3 is a schematic structural view of a first magnetic pole provided in the present invention;
FIG. 4 is a schematic structural diagram of a first magnetic pole provided by the present invention at another viewing angle;
FIG. 5 is a schematic structural view of a second magnetic pole provided in the present invention;
FIG. 6 is a schematic structural view of a second magnetic pole provided by the present invention at another viewing angle;
fig. 7 is a schematic diagram showing the comparison of cogging torque of magnetic steel in a symmetric structure and an asymmetric structure.
Wherein: 1 is a rotor iron core; 2 is a rotating shaft; 3 is a first magnetic steel; 4 is a second magnetic steel; 5 is a first magnetic pole; and 6 is a second magnetic pole.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-6, an embodiment of the present invention discloses a surface-mounted permanent magnet motor rotor asymmetric large and small magnetic pole structure, including: a rotor core 1, a shaft hole is arranged at the center of the rotor core 1, a rotating shaft 2 is installed in the shaft hole, a first magnetic steel 3 and a second magnetic steel 4 are arranged on the surface of the rotor core 1 along the axial direction of the rotor core 1, one first magnetic steel 3 is arranged, a plurality of second magnetic steels 4 are arranged, the first magnetic steel 3 and the plurality of second magnetic steels 4 are arranged on the surface of the rotor core 1 at intervals, the distance between the first magnetic steel 3 and the second magnetic steel 4 is equal to the distance between two adjacent first magnetic steels 3, wherein the arc length of the first magnetic steel 3 is larger than the arc length of the second magnetic steel 4, the lengths of the first magnetic steel 3 and the second magnetic steel 4 are equal to the length of the rotor core 1, the first magnetic steel 3 comprises a plurality of first magnetic poles 5, the plurality of first magnetic poles 5 are sequentially spliced along the axial direction of the rotor core 1 to form the first magnetic steel 3, the second magnetic poles 4 comprises a plurality of second magnetic poles 6, the plurality of second magnetic poles 6 are sequentially spliced along the axial direction of the rotor core 1 to form the second magnetic steels 4, the length of the first pole 5 is equal to the length of the second pole 6.
In this embodiment, preferably, the number of the first magnetic steels 3 is one, the number of the second magnetic steels 4 is seven, the radian between the first magnetic steel 3 and the adjacent second magnetic steel 4 is 13.5 °, the radian between two adjacent second magnetic steels 4 is also 13.5 °, the first magnetic steel 3 is formed by sequentially splicing four first magnetic poles 5, the second magnetic steel 4 is formed by sequentially splicing four second magnetic poles 6, specifically, the radian of the first magnetic pole 5 is 42 °, the radian of the second magnetic pole 6 is 30 °, the materials of the first magnetic pole 5 and the second magnetic pole 6 are rare earth permanent magnet boron (NdFeB) materials, and the shapes of the first magnetic pole 5 and the second magnetic pole 6 are tile-shaped, so that the inner surfaces of the first magnetic pole 5 and the second magnetic pole 6 are completely attached to the outer wall of the rotor core 1.
In the present embodiment, it is preferable that the first magnetic pole 5 and the second magnetic pole 6 each have a through hole at the center position, the rotor core 1 has a screw hole at the corresponding position of the outer surface of the rotor core and the first magnetic pole 5 and the second magnetic pole 6, and the first magnetic pole 5 and the second magnetic pole 6 are respectively connected to the rotor core 1 by screws.
The following takes the assembly of a surface-mounted permanent magnet motor rotor with 8 poles and 72 slots as an example, and further explains the asymmetric magnetic pole structure of the surface-mounted permanent magnet motor rotor through the assembly steps:
step 1: processing a threaded hole of a mounting screw on the surface of the rotor core 1 according to design requirements, and fixing the first magnetic pole 5 and the second magnetic pole 6;
step 2: penetrating the rotating shaft 2 into a shaft hole of the rotor core 1, and forming the rotating shaft 2 and the rotor core 1 into a whole;
and step 3: installing 1 first magnetic pole 5 on the rotor core 1, and fixing the first magnetic pole 5 on the rotor core 1 by using a screw; all the first magnetic poles 5 are assembled on the surface of the rotor core 1 in the mode, and a complete first magnetic steel 3 is formed;
and 4, step 4: installing 1 second magnetic pole 6 on the rotor core 1, and fixing the second magnetic pole 6 on the rotor core 1 by using a screw; in this way, all the second magnetic poles 6 in the same magnetic steel are assembled to the surface of the rotor core 1, and thus, the assembly of all the second magnetic steels 4 is completed.
Referring to fig. 7, a curve 1 is a graph of cogging torque and time of a rotor adopting an asymmetric magnetic pole structure, a curve 2 is a graph of cogging torque and time of a rotor adopting an asymmetric magnetic pole structure, and a graph of cogging torque and time of a uniform distribution structure, so that the rotor adopting the asymmetric magnetic pole structure is ensured to be identical to the rotor adopting the magnetic poles adopting the magnetic pole structure, and the usage amount of magnetic steel in the rotor adopting the uniform distribution structure is identical, i.e. the included angle between adjacent magnetic steel is 13.5 °, as can be seen from fig. 7, the maximum value of the cogging torque of the rotor adopting the asymmetric magnetic pole structure is 25.64Nm, the maximum value of the cogging torque of the rotor adopting the asymmetric magnetic pole structure is 3.53Nm, and the reduction rate of the cogging torque is 86.2% compared with the rotor adopting the magnetic pole structure which is completely identical to the magnetic pole structure and is uniformly distributed.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable 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 applied to other embodiments without departing from the spirit or scope of the utility model. 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.