KR100454730B1 - Attaching construction for permanent magnet of rotator of brushless dc motor - Google Patents

Abstract

The present invention relates to a permanent magnet attachment structure of a rotor of a non-commutator DC motor. When a plurality of N-pole permanent magnets and S-pole permanent magnets are sequentially attached to the outer circumferential or inner circumferential surface of the yoke 10 of the rotor of the non-commutator DC motor, the distance between the pair of N-pole permanent magnets and S-pole permanent magnets is The N-pole permanent magnet is attached to the yoke while attaching the pair of N-pole research magnets and S-pole permanent magnets to the yoke while maintaining the first interval (α). In the permanent magnet attachment structure of the rotor of the non-commutator DC motor to be spaced apart by β), the first interval α and the second interval β are such that the first interval α is the second interval. narrower than (β), and the first interval And the second interval (Θ is the magnet angle, P is the number of poles of the motor, S is the number of stator slots). According to the present invention, it is possible to simply reduce the ripple of the cogging torque and the counter electromotive force which affects the performance of the motor.

Description

ATTACHING CONSTRUCTION FOR PERMANENT MAGNET OF ROTATOR OF BRUSHLESS DC MOTOR}

A permanent magnet attachment structure of a rotor of a non-commutator DC motor. More specifically, the cogging torque is obtained by attaching the gap between the north pole and the south pole of the outer rotor to the inner outer surface of the outer rotor or the inner rotor at an uneven interval. It relates to a permanent magnet attachment structure of a rotor of a non-commutator DC motor which reduces the occurrence of torque and also prevents the waveform of counter electromotive force from preventing pulsation, that is, ripple.

In general, a non-commutator (brushless) DC motor has a long service life, and the electrical and mechanical noise does not occur according to the structure in which the commutator and the brush is removed, the use range is very wide. In addition, the non-commutator DC motor is a motor capable of variable speed control, and is mainly used to rotate any specific rotor at high speed and low speed as needed.

The non-commutator DC motor is composed of a stator for receiving a large current to generate a magnetic force, and a rotor rotatably installed on one side of the stator to rotate by the magnetic force generated in the stator.

The rotor is divided into an inner rotor installed inside the stator and an outer rotor installed outside the stator.

Meanwhile, as shown in FIG. 1, the permanent magnet 3 of the N pole and the permanent magnet 4 of the S pole are sequentially attached at equal intervals to the outer circumferential surface of the yoke 2 of the inner rotor 1. 2, the permanent magnet 7 of the N pole and the permanent magnet 8 of the S pole are sequentially attached at equal intervals to the inner circumferential surface of the yoke 6 of the outer rotor 5, as shown in FIG.

However, designing a motor with a slot generates cogging torque and also causes ripple in the back EMF, which affects the performance of the motor.

Thus, in order to block the generation of cogging torque in the process of designing a motor, a permanent magnet attached to the rotor is attached in the form of skew as shown in FIGS. 3 and 4 to block the generation of the cogging torque. 3 is a form in which the permanent magnets having the same pole are bonded to each other and skewed, and FIG. 4 is a form in which one permanent magnet is formed in a skew shape.

However, in order to attach the permanent magnets in the form as shown in FIG. 3, by attaching a plurality of permanent magnets having the same poles to each other, it is difficult to attach them due to the repulsive force generated between the same poles, and the manufacturing process due to attaching many permanent magnets. It takes a long time to assemble, difficult to automate by the machine, and also to attach the permanent magnet in the form as shown in Figure 4, the permanent magnet has a bent, it is difficult to manufacture by being formed obliquely, the method as described above In order to attach the permanent magnet in the form of skew, a work process is very difficult, and thus, a lot of time is consumed in the manufacturing process of the motor, and manufacturing cost increases.

Accordingly, an object of the present invention is to solve the above problems, and by forming the gap between the N pole and the S pole and the next N pole differently, the ripple of the cogging torque and the counter electromotive force is easily changed without a separate permanent magnet. To reduce the

1 is a cross-sectional view showing a state in which a permanent magnet is attached to the inner rotor of the conventional non- commutator DC motor

2 is a cross-sectional view showing a state in which a permanent magnet is attached to the outer rotor of the conventional non- commutator DC motor

3 is an explanatory diagram for explaining the structure of a permanent magnet attachment structure of a rotor of a conventional non-commutator DC motor;

4 is an explanatory diagram for explaining the structure of a permanent magnet attachment structure of a rotor of a conventional non-commutator DC motor;

5 is an explanatory diagram for explaining the configuration of a permanent magnet attachment structure of a rotor of a non-commutator DC motor according to the present invention.

Figure 6 is a cross-sectional view showing a permanent magnet attachment structure according to the invention applied to the outer rotor

7 is a graph comparing the cogging torque of a non-commutator direct current motor to which the present invention is applied and the cogging torque of a non-commutator direct current motor attached at equal intervals without conventional skew.

8 is a graph comparing the counter electromotive force waveform of the non-commutator DC motor to which the present invention is applied and the counter electromotive force waveform of the non-commutator DC motor attached at equal intervals without conventional skew.

<Description of the symbols for the main parts of the drawings>

10: yoke 20: a plurality of N-pole permanent magnets

30: A plurality of S-pole permanent magnets α: first interval β: second interval θ: magnet angle

The configuration of the present invention for achieving the above object is as follows.

In the structure of attaching a plurality of N-pole permanent magnets and S-pole permanent magnets sequentially attached to the outer circumferential surface or inner circumferential surface of the yoke 10 of the rotor of the non-commutator DC motor,

A first N pole permanent magnet 21 of a plurality of N pole permanent magnets is attached to the yoke 10, and a first S pole permanent magnet 31 of a plurality of S pole permanent magnets is attached to the first N pole permanent magnet. And a second gap (α) spaced apart from each other and attached to the yoke (10), and a second N pole permanent magnet (22), which is the next N pole permanent magnet, is spaced apart from the first S pole permanent magnet and the second gap (β). The permanent magnets are disposed in such a manner that the second S-pole permanent magnets 32, which are the next S-pole permanent magnets, are spaced apart from each other by the third N-pole permanent magnets 32 at a first interval α. The invention is a numerically limited improvement of a known technology for attaching permanent magnets to a rotor of a non-commutator DC motor. The configuration of the present invention provides a structure in which the permanent magnet is attached to the rotor of the non-commutator DC motor. It is an invention in which the angle between the pole permanent magnet and the S pole research magnet is limited as follows. That is, the gap between the pair of N pole permanent magnets and the S pole permanent magnets is attached to the yoke while maintaining the first interval (α), and the other pair of N pole permanent magnets and S pole permanent magnets are attached to the yoke. The N-pole permanent magnet is spaced apart by a second interval β from the attached S-pole permanent magnet, but the first interval α and the second interval β are

The first interval is narrower than the second interval,

The first interval to be. Where θ is the magnet angle, P is the number of poles of the motor, and S is the number of stator slots. Also,

The second interval , Where α + β is

Or Is,

It is characterized by that.

Hereinafter, the configuration and operation of the permanent magnet attachment structure of the rotor of the non-commutator DC motor according to the present invention will be described in detail with reference to FIGS. 5 and 6.

5 is an explanatory view for explaining the configuration of the permanent magnet attachment structure of the rotor of the non-commutator DC motor according to the present invention, Figure 6 is a permanent magnet attachment structure of the non-commutator DC motor according to the present invention to the outer rotor This is a cross-sectional view showing the appearance.

5 and 6, the permanent magnet attachment structure of the non-commutator DC motor according to the present invention attaches the first N pole permanent magnet 21 to the yoke 10 of the plurality of N pole permanent magnets 20. The first S-pole permanent magnet 31 of the plurality of S-pole permanent magnets 30 is spaced apart from the first N-pole permanent magnet 21 at a first interval α, and then attached to the yoke 10. 2 … The n-pole permanent magnets 22... 25 are attached to the first S-pole permanent magnets 31 at a second interval beta, and then the second. n S-pole permanent magnets 32... The N-pole permanent magnets 22... 25 are spaced apart from each other at a first interval α. Here, the first interval α is narrower than the second interval β,

The first interval α and the second interval β are obtained by the following equations (1) and (2).

In Equation 1 and Equation 2 to be.

Also Or to be.

In addition to be.

Θ is the magnet angle, P is the number of poles of the motor, S is the number of fault slots, and all angles are mechanical angles.

More specifically, when the rotor of the non-commutator DC motor is composed of five N pole permanent magnets and five S pole permanent magnets as shown in FIG. 5, the first N pole permanent magnet 21 may be yoke 10. ), And attach the first S-pole permanent magnet 31 at a first interval α, and then attach the second N-pole permanent magnet 22 at a second interval β, and The pole permanent magnet 32 is attached at the first interval α, the third N pole permanent magnet 23 is attached again at the second interval β, and the third S pole permanent magnet 33 is attached to the first gap. The fourth N-pole permanent magnet 24 is attached at the second interval β, and the fourth S-pole permanent magnet 34 is attached at the first interval α. Then, the fifth N-pole permanent magnet 25 is attached again at the second interval β, and the fifth S-pole permanent magnet 35 is attached at the first interval α. That is, the gap between the pair of N pole permanent magnets and the S pole permanent magnet is attached to the yoke while maintaining the first interval, and the other pair of N pole permanent magnets and the S pole permanent magnet that are already attached when the other pair of N pole permanent magnets and the S pole permanent magnets are attached to the yoke. The N pole permanent magnet is attached to the S pole permanent magnet at a second interval.

Hereinafter, the operation of the permanent magnet attachment structure of the rotor of the non-commutator DC motor according to the present invention will be described in detail with reference to FIGS. 7 and 8.

7 is a graph comparing the cogging torque of the non-commutator DC motor to which the present invention is applied and the cogging torque of a conventional non-commutator DC motor attached at equal intervals without skew, and FIG. 8 is a graph of the non-commutator DC motor to which the present invention is applied. It is a graph comparing the counter electromotive force waveform and the counter electromotive force waveform of the conventional non-commutator DC motor attached at equal intervals without skew.

Referring to FIGS. 7 and 8, when the N pole permanent magnet 20 and the S pole permanent magnet 30 are attached to the yoke 10 at an uneven interval, there is no conventional skew as shown in FIG. 7 and the permanent magnet. The cogging torque having a ripple relatively smaller than the cogging torque output from the non-commutator DC motors attached at equal intervals is output, and as shown in FIG. 8, there is no conventional skew and no permanent magnet is attached at equal intervals. The counter electromotive force with less ripple is output than the counter electromotive force output from the commutator DC motor.

As described above, according to the permanent magnet attachment structure of the rotor of the non-commutator DC motor according to the present invention, the gap between the N pole and the S pole attached to the yoke of the rotor without deformation of the permanent magnet is attached at an unequal interval. By doing so, the ripple of cogging torque and back EMF can be reduced.

Claims (2)

delete When a plurality of N pole permanent magnets and S pole permanent magnets are sequentially attached to the outer circumferential surface or the inner circumferential surface of the yoke 10 of the rotor of the non-commutator DC motor, the distance between the pair of N pole permanent magnets and the S pole permanent magnets is zero. The N pole permanent magnet is attached to the S pole permanent magnet attached to the yoke 10 while maintaining one interval (α), and the other pair of N pole research magnets and S pole permanent magnets are attached to the yoke 10. In the permanent magnet attachment structure of the rotor of the non-commutator DC motor, characterized in that spaced apart by a second interval β, The first interval α and the second interval β have a smaller first interval α than the second interval β, The first interval Where θ is the magnet angle, P is the number of poles of the motor, and S is the number of stator slots, The second interval , Where α + β is Or Is, Permanent magnet attachment structure of the rotor of the non-commutator DC motor, characterized in that.