KR20170047563A - The stator improving the asymmetry of magnetic flux density in the unipolar type and step motor comprising the same - Google Patents

Abstract

According to the present invention, disclosed is a stator with improved asymmetry of a magnetic flux density in a unipolar driving scheme, and a step motor having the same. The stator comprises: a stator core formed in a ring shape, and including a plurality of stator salient poles extended toward the center from a ring-shaped internal circumference; and a plurality of stator wires wound on the plurality of stator salient poles, respectively, in a forward direction and a reverse direction.

Description

[0001] The present invention relates to a stator for improving magnetic flux density asymmetry in a unipolar driving method, and a step motor including the stator for improving the magnetic flux density asymmetry.

More particularly, the present invention relates to a stator that improves the asymmetry of magnetic flux density in a unipolar driving system in which stator windings are formed in a double structure of forward and reverse directions to secure symmetry of magnetic flux density, and To a stepping motor.

)상에 플러스 방향 전류가 흐르고, 역A(

)상 및 B상에 마이너스 방향 전류가 흐른다. Generally, in the case of the two-phase excitation method, the unipolar driving method has a difference that the current flows in the plus (+) direction while the bipolar driving method flows in the plus direction and the minus (-) direction . Therefore, in the unipolar driving method, the current changes in steps and the current flows in the positive direction on the two phases. In the bipolar driving method, the A phase and the B

), A positive direction current flows in the reverse A (

) Phase and B phase.

In this case, the bipolar driving method has symmetry by forming two poles, while the unipolar driving method has no symmetry, and is formed with three poles. Therefore, it is not suitable to generate a torque. Even if a minute torque is generated, Vibration and noise are largely generated.

In order to overcome such a problem, a conventional unipolar stepping motor has a two-stage structure in which a stator or a rotor crosses axially. However, the two-stage configuration is complicated to manufacture and assemble as compared with the one-stage configuration, and has a disadvantage that many mechanical components are added.

Therefore, efforts have been made to improve the asymmetry of the magnetic flux density by adopting the step motor as one stage while applying the unipolar driving method.

Korean Patent Registration No. 10-0245483 (Feb.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stator having improved magnetic flux density asymmetry in a unipolar driving system in which stator windings are wound in a forward and a reverse bi-directional structure, and a step motor including the stator.

It is another object of the present invention to provide a stator having improved magnetic flux density asymmetry in a unipolar driving method for reducing a radial force of a rotor and a stator, and a step motor including the stator .

In order to achieve the above object, a stator having improved magnetic flux density asymmetry in a unipolar driving system is formed in a ring shape, and includes a plurality of stator salient poles extending from the inner periphery of the ring shape toward the center, And a plurality of stator windings wound in forward and reverse directions on the plurality of stator salient poles, respectively.

The plurality of stator windings are wound in a twisted shape in the forward and reverse directions.

And the plurality of stator windings are made to have the same number of windings with respect to the forward direction and the reverse direction.

A step motor including a stator that improves magnetic flux density asymmetry in a unipolar drive system is formed in a rotor and a ring shape including a permanent magnet and connected to a rotating shaft, Wherein the stator comprises: a stator core including a plurality of stator salient poles extended in the center direction from the ring-shaped inner periphery; and a plurality of stator windings wound on the stator salient poles in forward and reverse directions, respectively, Winding.

Further, a one-phase excitation system or a two-phase excitation system is applied.

And also reduces the radial force of the rotor and the stator.

According to the stator having improved magnetic flux density asymmetry in the unipolar driving method and the step motor including the stator, the symmetry of the magnetic flux density can be ensured by winding the stator winding by the double structure of forward and reverse directions.

In addition, the radial forces of the rotor and the stator can be reduced to reduce noise and vibration.

In addition, it is possible to reduce the cost by symmetrically implementing a magnetic asymmetric structure by constructing only the pattern of the stator winding as a twist without twisting the shape of the permanent magnet or the stator in the direction of the rotating shaft.

1 is a view for explaining a stator winding for a step motor according to an embodiment of the present invention.
2 is a view for explaining a magnetic flux pattern to which a unipolar driving method of a stepping motor is applied according to an embodiment of the present invention.
FIG. 3 is a view for explaining an air gap magnetic flux distribution applied to a bipolar drive system and a unipolar drive system of a step motor according to an embodiment of the present invention.
4 is a view for explaining an air gap magnetic flux distribution applying a unipolar driving method of a step motor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals as used in the appended drawings denote like elements, unless indicated otherwise. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather obvious or understandable to those skilled in the art.

FIG. 1 is a view for explaining stator windings for a step motor according to an embodiment of the present invention. FIG. 2 is a view for explaining a magnetic flux pattern using a unipolar driving method of a step motor according to an embodiment of the present invention. FIG.

Referring to Figs. 1 and 2, the step motor 1 improves the asymmetry of the magnetic flux density in the unipolar driving method to reduce the radial force of the stator 10 and the rotor 20.

The step motor 1 includes a stator 10, a rotor 20, and a rotary shaft 30. The rotary shaft 30 is provided at the center of the step motor 1 and connected to the rotor 20 so that the rotor 20 rotates as the rotary shaft 30 rotates. The rotor 20 includes a permanent magnet and is provided inside the stator 10. [ At this time, when the rotor 20 is rotated by the rotating shaft 30, the permanent magnets included in the rotor 20 and the stator windings 13, 15, 17, and 19 wound around the stator 10 And magnetism is generated between them to generate a current.

At this time, the step motor 1 can be applied by a one-phase excitation method or a two-phase excitation method.

Therefore, the step motor 1 includes a stator 10 capable of improving magnetic flux density asymmetry in a unipolar driving system, and the stator 10 includes a stator core 11 and a plurality of stator windings (13, 15, 17, 19).

The stator core 11 is formed in a ring shape and includes a plurality of stator salient poles 11a, 11b, 11c, and 11d extending in the center direction from the inner periphery of the ring shape. The stator core 11 can be formed with a plurality of stator salient poles 11a, 11b, 11c, and 11d at a certain angle. At this time, the extended length of the plurality of stator salient poles 11a, 11b, 11c, and 11d is spaced apart from the rotor 30 by a predetermined distance.

The plurality of stator salient poles 11a, 11b, 11c and 11d can be classified into a first stator salient pole 11a, a second stator salient pole 11b, a third stator salient pole 11c and a fourth stator salient pole 11d , And the first to fourth stator salient poles 11a, 11b, 11c, and 11d may be formed at an angle of 90 with respect to each other.

The number of the stator poles 11a, 11b, 11c, and 11d is not limited to four as shown in Fig. For example, the plurality of stator salient poles may include a stator salient pole formed by an even number such as 6, 8, 10, 12, or a stator salient pole formed by an asymmetric odd number.

The plurality of stator windings 13, 15, 17, and 19 are wound in the forward and reverse bi-structures in the first to fourth stator salient poles 11a, 11b, 11c, and 11d, respectively. Preferably, the plurality of stator windings 13, 15, 17, and 19 may be wound in a twisted shape.

The first stator pole piece 11a and the second stator pole piece 11b are wound around a first stator winding 13 which is an exciting winding on the A phase and a second stator winding 15 which is an exciting winding on the reverse A phase. The first stator pole piece 11a and the second stator pole piece 11b can be wound such that the first stator winding 13 is closer to the rotor 30 than the second stator winding 15. The first stator winding 13 and the second stator winding 15 are wound in opposite directions to each other.

For example, when a current flows from the second stator pole 11b toward the first stator pole 11a, the winding direction of the first stator coil 13 is set to the N pole of the first stator pole 11a , And the second stator hollow poles 11b are set to the S poles. The winding direction of the second stator winding 15 is such that the first stator pole piece 11a is set to the S pole and the second stator pole piece 11b is set to the N pole.

At this time, the number of times the windings are wound is the same for the first stator winding 13 and the second stator winding 15. That is, the number of turns for the forward and reverse directions is the same.

The third stator pole piece 11c and the fourth stator pole piece 11d are wound around the third stator winding 17 which is the exciting winding of the B phase and the fourth stator winding 19 which is the exciting winding of the reverse B phase. The third stator emissive pole 11c and the fourth stator emissive pole 11d can be wound such that the third stator winding 17 is closer to the rotor 30 than the fourth stator winding 19. [ The third stator winding 17 and the fourth stator winding 19 are wound in opposite directions to each other.

For example, when a current flows from the fourth stator emissive element 11d toward the third stator emissive element 11c, the winding direction of the third stator winding 17 is set such that the third stator embrittlement pole 11c is set to the N pole And the fourth stator salient pole 11d is set to the S pole. The direction in which the fourth stator winding 19 is wound is set such that the third stator pole piece 11c is set to the S pole and the fourth stator pole piece 11d is set to the N pole.

At this time, the number of times the windings are wound is the same for the third stator winding 17 and the fourth stator winding 19. That is, the number of turns for the forward and reverse directions is the same.

The step motor 1 forms stator windings 13, 15, 17 and 19 in both forward and reverse directions to the first to fourth stator salient poles 11a, 11b, 11c and 11d to form a winding pattern of a dual structure . The step motor 1 always has the same flux component pattern as the bipolar method regardless of the unipolar driving method and the bipolar driving method through the patterns of the stator windings 13, 15, 17 and 19.

For example, when the N pole is the first stator pole pole 11a and the S pole is the second stator pole pole 11b, the magnetic flux pattern applied by the unipolar driving method of the step motor 1 is the first stator pole pole 11a , The negative direction of the A phase and the minus direction of the A phase and the positive direction of the A phase are symmetrical with respect to the A phase and the A phase and the positive direction on the A side are symmetrical with respect to the second stator pitch 11b, Minus direction of the B phase and the plus direction of the B phase and the plus direction of the B phase are symmetrical with respect to the third stator missed salient pole 11c And the negative direction of the B phase and the positive direction of the B phase and the positive direction of the B phase are symmetrical with respect to the negative direction of the B phase and the negative direction of the B phase and the positive direction of the B phase with respect to the fourth stator salient pole 11d, a) and the second stator salient pole 11b as a reference, and a magnetic flux is formed.

Therefore, even when the stepping motor 1 is of the unipolar driving type, the magnetic flux component pattern has a symmetrical structure, and thus is magnetically stable. Thus, the stepper motor 1 has excellent performance in vibration and noise.

In particular, it is possible to reduce the cost by symmetrically implementing a magnetic asymmetric structure by constructing only the pattern of the stator winding as a twist without twisting the shape of the permanent magnet or the stator in the direction of the rotating shaft.

FIG. 3 is a view for explaining an air gap magnetic flux distribution applied to a bipolar drive system and a unipolar drive system of a stepper motor according to an embodiment of the present invention, and FIG. 4 is a cross- Fig. 8 is a view for explaining the distribution of air fluxes applied with the method of Fig.

Referring to FIG. 3 and FIG. 4, the performance test was performed by varying the stator winding pattern and the driving method in the same step motor including ten stator salient poles. 3 (a)). The second performance test is an experiment (Fig. 3 (b)) in which a unipolar driving method is applied to a general winding pattern, 3 performance test is an experiment (Fig. 4) in which a unipolar driving method is applied to a winding pattern according to the present invention.

The first performance test is symmetric and has a void flux distribution, whereas the second performance experiment has an asymmetric void flux distribution, so that the radial forces acting on the rotor are asymmetric. Therefore, when the unipolar driving method is applied through the conventional winding pattern, it is impossible to obtain a symmetric air magnetic flux distribution like the bipolar driving method.

However, through the third performance test, the step motor according to the present invention has a symmetrical air magnetic flux density characteristic even in the unipolar driving method, thereby proving that the asymmetric structure is improved.

Therefore, the step motor according to the present invention has a magnetically stable structure, and thus has excellent performance against vibration and noise.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

1: Step motor
10: Stator
11: stator core
11a: first stator pole pole
11b: second stator pole piece
11c: third stator pole pole
11d: fourth stator pole pole
13: first stator winding
15: second stator winding
17: Third stator winding
19: fourth stator winding
20: Rotor
30:

Claims (6)

A stator core formed in a ring shape and including a plurality of stator salient poles extending in the center direction from the inner periphery of the ring shape; And
A plurality of stator windings wound in forward and reverse directions on the plurality of stator salient poles, respectively;
Wherein the asymmetry of the magnetic flux density is improved in the unipolar driving method. The method according to claim 1,
Wherein the plurality of stator windings comprise:
Wherein the stator is wound in the forward and reverse directions in a twisted shape, wherein the asymmetry of magnetic flux density is improved in a unipolar driving method. The method according to claim 1,
Wherein the plurality of stator windings comprise:
Wherein the number of turns of the stator is equal to the number of turns of the stator in the forward and backward directions. A rotor connected to the rotating shaft and including a permanent magnet; And
And a stator formed in a ring shape and having the rotor inside the ring shape,
The stator comprises:
A stator core including a plurality of stator salient poles extending in the center direction from the ring-shaped inner periphery; And
A plurality of stator windings wound in forward and reverse directions on the plurality of stator salient poles, respectively;
Wherein the asymmetry of the magnetic flux density is improved in a unipolar drive system including a stator. 5. The method of claim 4,
Wherein the one-phase excitation system or the two-phase excitation system is applied to the stator of the stator, wherein the asymmetry of the magnetic flux density is improved. 5. The method of claim 4,
Wherein a radial force of the rotor and the stator is reduced. The stator includes a stator having improved magnetic flux density asymmetry in a unipolar driving method.

Images