CN202153702U

CN202153702U - Structure for reducing torque ripple of brushless direct current motor

Info

Publication number: CN202153702U
Application number: CN2011200578827U
Authority: CN
Inventors: 李军丽; 李秀英; 苗国辉
Original assignee: Shanghai Electrical Apparatus Research Institute Group Co Ltd
Current assignee: Shanghai Electrical Apparatus Research Institute Group Co Ltd
Priority date: 2011-03-08
Filing date: 2011-03-08
Publication date: 2012-02-29
Anticipated expiration: 2021-03-08

Abstract

The utility model relates to a structure for reducing the torque ripple of a brushless direct current motor. The structure comprises magnetic steel 1, a rotor magnetic yoke 2, a key 3 and a rotating shaft 4, and is characterized in that the pole arc width of the magnetic steel 1 reduces from 90 degrees to 76.9 degrees, the positions of the rotor magnetic yoke 2, the key 3, and the rotating shaft 4 do not change, an improved cogging torque is 1.5% of a rated torque for the reason that the pole arc width of the magnetic steel 1 is changed, and a cogging torque is greatly reduced by improving the pole arc width of a permanent magnet, that is to say, by changing a mechanical angle occupied by the permanent magnet in space, thus the torque ripple is reduced. The structure not only reduces the vibration and noise of the brushless direct current motor, but also reduces the using of magnetic steel, reduces total loss, and improves the efficiency of the motor.

Description

Reduce the structure of brshless DC motor torque pulsation

Technical field

The utility model relates to a kind of structure that reduces the brshless DC motor torque pulsation, reduces the method for brshless DC motor torque pulsation in other words, belongs to technical field of motors.

Background technology

The magnetic field that permanent magnet produced on the brshless DC motor rotor attracts each other with the tooth in the stator armature iron core, and its active force makes rotor that a kind of trend of aliging with stator along a certain specific direction arranged in the torque that component produced of circumferencial direction.

This torque is exactly a cogging torque, also is referred to as reluctance torque.It is the one of the main reasons that the brshless DC motor torque produces pulsation.Rotor structure is as shown in Figure 1, is magnet steel, rotor yoke, machine shaft from outside to inside successively.Magnet steel sticks on the rotor yoke surface, and rotor yoke links up through key and machine shaft.

In variable speed drives, when the natural machanical frenquence of the frequency of cogging torque and stator or rotor is identical, just caused resonance, make the vibration of motor and noise increase.The existence of cogging torque has influenced low-speed performance and the hi-Fix in Position Control of motor in speed control system equally.

On structural design, reduce cogging torque, make torque pulsation reach desirable situation through improving the polar arc width.

Structure before improving, cogging torque is about 23% of a nominal torque, situation is Cui not, for this reason, must improve the polar arc width of permanent magnet, reduces the torque pulsation of motor.

Summary of the invention

The utility model relates to the structure that reduces the brshless DC motor torque pulsation, and cogging torque is about 1.5% of a nominal torque after this architecture advances.

For achieving the above object, the technical scheme of the utility model is: rotor is made up of magnet steel, rotor yoke, key, rotating shaft, and rotating shaft is in the bosom, and magnet steel has key on the surface of rotor yoke between rotating shaft and the rotor yoke.Through improving the polar arc width of permanent magnet, promptly change the permanent magnet mechanical angle shared in the space, make cogging torque reduce significantly, thereby torque pulsation also reduce.

The beneficial effect of the utility model: through improving the polar arc width of permanent magnet; Make cogging torque reduce significantly, thereby torque pulsation has also reduced, so not only improved the vibration and the noise of brshless DC motor; Also saved magnet steel; Reduce iron loss and copper loss, thereby improved efficiency of motor, had certain economic benefits.

Below in conjunction with accompanying drawing and embodiment to the utility model detailed explanation of making comparisons.

Description of drawings

Fig. 1 is the rotor structure sketch map of prior art;

Fig. 2 is the rotor structure sketch map of the utility model.

Embodiment

With reference to Fig. 2, this is the rotor structure sketch map of the utility model.

As shown in the figure, rotor structure comprises magnet steel 1, rotor yoke 2, key 3, rotating shaft 4, and rotating shaft has key in the bosom between rotating shaft and the rotor yoke, changes magnet steel 1 polar arc width, reduces to 76.9 degree, rotor yoke 2, key 3, rotating shaft 4 invariant positions from 90 degree.Owing to change magnet steel 1 polar arc width, improving the back cogging torque is 1.5% of nominal torque.

Through improving the polar arc width of permanent magnet, promptly change the permanent magnet mechanical angle shared in the space, make cogging torque reduce significantly, thereby torque pulsation has also reduced.Like this, not only improve the vibration and the noise of brshless DC motor, also saved magnet steel, reduced iron loss and copper loss, improved efficiency of motor.

Claims

1. structure that reduces the brshless DC motor torque pulsation; This structure comprises magnet steel (1), rotor yoke (2), key (3), rotating shaft (4); Rotating shaft has key in the bosom between rotating shaft and magnet steel, the rotor yoke, it is characterized in that: magnet steel (1) polar arc width reduces to 76.9 degree from 90 degree; Rotor yoke (2), key (3), rotating shaft (4) invariant position, improving the back cogging torque is 1.5% of nominal torque.