CN1725599B - Rotor structure of built-in permanent magnet brushless motor - Google Patents

Abstract

The invention discloses a rotor structure of a built-in permanent magnet brushless motor, which comprises: the stator is provided with a winding slot formed by winding coils on the silicon steel lamination; the rotor comprises a plurality of empty grooves, and magnets slightly smaller than the empty grooves are correspondingly arranged in the empty grooves so as to form a gap between the empty grooves and the outer edges of the magnets in the radial direction; the advantage of this design is that the permanent magnet does not need to be designed additionally, and only needs to be made into a general long rectangular shape, and the motor rotor can be kept in a normal cylindrical shape, so that the permanent magnet motor structure with high efficiency, high torque and low cogging torque can be achieved at the most economical manufacturing cost.

Description

Rotor structure of built-in permanent magnet brushless motor

technical field

The invention relates to a rotor structure of a built-in permanent magnet brushless motor, in particular to a special-shaped hollow groove formed by silicon steel sheets around the permanent magnet in the motor rotor, and the hollow groove must cover the magnetic flux path to the magnet. In the direction of the region, the reluctance of the slot is used to adjust the distribution of the magnetic flux density in the space between the motor stator and the rotor, so that the back electromotive force waveform and torque characteristics of the motor can reach the design target structure.

Background technique

Electric motor (motor) is an indispensable important device in modern industry. It is widely used in various electrical appliances, transportation systems, etc. Its main action principle is to convert electrical energy into mechanical energy to drive machinery to do Rotate or vibrate...etc. In terms of how to use limited volume and materials to achieve greater torque, and maintain high efficiency and high control accuracy, built-in permanent magnet brushless motors are often the best choice.

The known permanent magnet brushless motor structure, as disclosed in US Patent No. 6,177,745, utilizes magnets with different poles, and changes the material and shape of the magnets to adjust their magnetic flux density and increase their reluctance torque. In addition, as disclosed in U.S. Patent No. 6,340,857, it uses two separate magnets, and an insulating layer is arranged in them. The insulating layer can suppress eddy currents to avoid the "thermal demagnetization" effect of the magnets. The above two patents are all aimed at the rotor. Improved structure designed on permanent magnets.

Another type of structural improvement of the known permanent magnet motor, please refer to US patent US 6,008,559, which directly digs an empty slot between the two pole magnets in the rotor and the outer edge of the rotor to avoid the "magnetic short circuit" effect and further improve Torque, and can reduce the Cogging Torque, and further reduce vibration and noise. Please refer to US Patent No. 6,034,458, which discloses a structure in which two magnetic poles are hollowed out to form a non-circular shape of the rotor, and an empty slot for avoiding magnetic short circuit is formed. Please refer to US Patent No. 6,218,753, which changes the space between the two-pole magnet and the outer edge of the rotor into an asymmetrical space, and improves its assembly structure. Please refer to U.S. Patent No. 6,674,205, which adds magnets to the cavity on the rotor of the conventional reluctance motor to form an auxiliary magnetic circuit, and pre-forms a magnetic field to increase the torque.

The known built-in permanent magnet motors are all adjusted in the shape and arrangement of the permanent magnets, or the silicon steel sheets of the rotor are made into multi-layer air gaps to form a structure with high efficiency and high torque, but the aforementioned The two improved structures, either because the magnets are more difficult to manufacture, or because the shape of the rotor silicon steel sheet is too complicated, there are various defects. Therefore, when the precision of the magnet or the rotor silicon steel sheet is not good, it is easy to cause performance. Problems such as poor torque.

Contents of the invention

The purpose of the present invention is to provide a rotor structure of a built-in permanent magnet brushless motor, which can achieve high efficiency, high torque and low cogging torque under the premise of relatively simple motor manufacturing process and assembly.

In order to achieve the above object, the present invention provides a rotor structure of a built-in permanent magnet brushless motor, including:

A stator, the stator is composed of coils wound on a silicon steel sheet, and the stator includes several winding slots; and

A rotor, the rotor includes several empty slots, the empty slots cover the area in the radial direction to the magnetic flux of the permanent magnet, and a magnet with a size and volume slightly smaller than the empty slots is correspondingly arranged inside the empty slots to form the empty slots There is at least one gap between the groove and the magnet on the radially outer edge of the rotor, and the gap includes a portion in the radial direction of the magnetic flux of the permanent magnet.

The invention utilizes the silicon steel sheet around the permanent magnet in the motor rotor to form a special-shaped slot, which must cover the area in the direction of magnetic flux to the magnet, and uses the reluctance of the slot to adjust the distance between the motor stator and the rotor. The distribution of the spatial magnetic flux density makes the distribution of the spatial magnetic flux density between the motor stator and the rotor, so that the motor's back electromotive force waveform and torque characteristics meet the design goals. The advantage of this design is that the shape of the permanent magnet does not need to be specially designed, it only needs to be made into a general long rectangular shape, and the shape of the motor rotor can also maintain a general cylindrical shape, so it can be achieved at the most economical production cost. High efficiency, high torque and low cogging torque permanent magnet motor structure.

The invention can reduce the armature reaction, increase the reluctance torque, reduce the electric harmonic wave and improve the power factor of the electric system.

Through the following detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, the above-mentioned purpose, effect and technical content of the present invention can be further understood.

Description of drawings

Fig. 1 is a partial cross-sectional side view schematic diagram of the first implementation structure of the built-in brushless motor of the present invention;

Fig. 2 is a schematic cross-sectional side view of the second implementation structure of the built-in brushless motor of the present invention;

FIG. 3 is a waveform schematic diagram of the structure disclosed in FIG. 1 and FIG. 2 of the present invention that can solve the torque waveform surge.

Description of reference signs: 1 stator; 11 winding slot; 2 rotor; 21 first empty slot; 211 first gap; 22 first magnet; 3 stator; 31 winding slot; 4 rotor; 41 second empty slot; 411 2nd gap; 42 second magnet; 5 surge.

Detailed ways

Please refer to FIG. 1 , which is a partial cross-sectional side view of the first implementation structure of the built-in brushless motor of the present invention, wherein the rotor 2 of the motor has a perfect circular shape, and the first magnet 22 has a square shape. According to the number of poles of the motor to be designed, the first magnet 22 is evenly built into the rotor 2, and there is a special shape around the second magnet 22 and an appropriate first cavity 21 is desired. The first cavity 21 accommodates the first magnet. After 22, at least the first gap 211 is reserved, and the present embodiment discloses that the first gap 211 is reserved at both ends of the first magnet 22. Of course, those skilled in the art can also place any gaps on the outer edge of the first magnet 22. One place is provided with gaps of different shapes, all of which are the same technical means as in this embodiment. When designing, directly design the rotor 2 of the entire motor, including the material (silicon steel sheet) of the rotor 2, the shape of the first cavity 21 and the width and height of the first magnet 22 to be formed. The silicon steel sheets are stamped and formed, stacked to the desired stacked length, and then fixed into a cylinder with automatic riveting or rivets, and then the surface of the designed and manufactured square permanent magnet is coated with glue and placed directly into the rotor 2, so that the manufacture of the motor rotor 2 is completed, and the setting of the first gap 211 can effectively prevent the short circuit of the magnetic force lines, and achieve high efficiency, high torque and low cogging torque permanent magnet motor the goal of.

In addition, the stator 1 of the motor has several winding slots 11 , and the present invention does not improve the structure of the stator 1 , so it will not be repeated here.

Please refer to FIG. 2 for a schematic cross-sectional side view of the second implementation structure of the built-in brushless motor of the present invention, wherein the stator 3 of the motor has not undergone any structural changes, and will not be described in detail. The improved part of this embodiment is still the gap setting between the second magnet 42 of the rotor 4 and the second cavity 41. The difference from the first embodiment is that the second magnet 42 is not designed as a long rectangle. It is that one of the two ends of the long side of the second magnet 42 is cut at an oblique angle to form a hexagonal second magnet 42, while the second hollow 41 is designed as a long rectangle so that the second magnet 42 When accommodated in the second cavity 41, a second gap 411 with two triangular shapes is formed. The second gap 411 is located in the radial direction of the magnetic flux, and the setting of the second gap 411 can effectively prevent The phenomenon of "magnetic short circuit" achieves the purpose of permanent magnet motor with high efficiency, high torque and low cogging torque.

The structure of the permanent magnet brushless motor disclosed in the above two embodiments includes the following features:

(1) The permanent magnets including even-numbered poles are built into the rotor, and the permanent magnets have the same material, size, and shape.

(2) The rotor of the permanent magnet motor is made of laminated silicon steel sheets. Each silicon steel sheet has an empty slot slightly larger than the shape and size of the permanent magnet. After the permanent magnet is placed, there is at least one gap.

(3) The empty slots around the permanent magnets are directly connected with the permanent magnets. The empty slots where the permanent magnets are placed and the remaining gaps are integrally formed without any original silicon steel sheet material. The gaps are not limited to any shape, but must be included in the permanent magnet. The portion in the radial direction of the magnet flux.

(4) The permanent magnet brushless motor rotor is placed in the permanent magnet slot, and silicon steel sheets with sufficient mechanical strength must be left to support the rotor and separate permanent magnets of different polarities.

Please refer to Fig. 3, which is a schematic diagram showing that the structures disclosed in Fig. 1 and Fig. 2 of the present invention can solve the problem of torque waveforms producing surges. Originally, a torque sine wave generates a surge at its positive half-cycle trailing edge and negative half-cycle leading edge. 5. Through the rotor structure shown in Fig. 1 and Fig. 2, the surge 5 can be eliminated, the original curve can be restored to a smooth sinusoidal waveform, and the sudden rotation phenomenon of the motor caused by the bump can also be eliminated.

1 to 3, it can be understood that the technical means disclosed in the present invention can indeed reduce the armature reaction, increase the reluctance torque and adjust the distribution of the space magnetic flux density between the motor stator and rotor, so that the motor reverse The electromotive force waveform and torque characteristics meet the design goals.

The above descriptions are only preferred embodiments of the present invention, and should not limit the implementation scope of the present invention. Therefore, all equivalent changes and modifications made according to the claims of the present invention should still belong to the protection scope of the present invention.

Claims (5)

1. the rotor structure of a built-in permanent magnetic brushless motor comprises:

One stator, this stator is made of coiling on the silicon steel sheet, and this stator comprises several winding slots; And

One rotor, comprise several dead slots in this rotor, described dead slot is contained to the zone of the radial direction of permanet magnet magnetic flux, the inner correspondence of this dead slot is provided with the magnetite that size, volume are slightly less than dead slot, this dead slot and magnetite are intermarginal outside rotor radial to have a gap at least to form, and described gap is included in the part of the radial direction of permanet magnet magnetic flux.

2. the rotor structure of built-in permanent magnetic brushless motor as claimed in claim 1, wherein the material of the permanet magnet of this rotor, size, shape are all identical.

3. the rotor structure of built-in permanent magnetic brushless motor as claimed in claim 1, wherein this rotor is formed by the silicon steel sheet stack.

4. the rotor structure of built-in permanent magnetic brushless motor as claimed in claim 1, wherein the profile of this magnetite is a long rectangle.

5. the rotor structure of built-in permanent magnetic brushless motor as claimed in claim 1, wherein the profile of this magnetite is that two ends, long rectangle one long limit are dissectd with the angle of inclination, to form a hexagonal profile.

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