KR102425813B1 - Stator for minimizing cogging torque - Google Patents

Abstract

A stator structure is provided that minimizes cogging torque. The stator structure for minimizing the cogging torque includes a stator formed in an annular shape, a rotor disposed coaxially and rotatably of the stator, and a predetermined width such that a coil is wound around the stator, and protrudes toward the rotor. and a stator tooth provided with a plurality of protrusions, a slot formed in a space adjacent to each other of the stator tooth, and an insertion member inserted into the slot.

Description

Stator structure to minimize cogging torque

The present invention relates to a stator structure, and more particularly, to a stator structure that minimizes cogging torque.

Recently, a permanent magnet (PM) motor has been used in various types of devices, such as a traction device, a lifting device, and a refrigerator.

Permanent magnet motors are widely used because of their high efficiency, simplicity, low noise and reliability.

However, there is a disadvantage in that a high torque ripple is generated due to the cogging torque of the permanent magnet motor.

Due to the magnetic force (attractive force) generated between the permanent magnet mounted on the rotor and the teeth of the stator, the cogging torque is larger in the SPM motor.

Cogging torque is a torque generated by the magnetic force between the permanent magnet of the motor's rotor and the slot of the stator.

In other words, as long as there is a stator or a slot, the cogging torque is generated regardless of the flow of current, so-called detent torque.

Cogging torque is not only a major cause of torque ripple, but also a cause of vibration and noise, and is also a major cause of reducing efficiency.

Cogging torque is generated in a stator having an iron core and a slot, and is generally generated by an imbalance of magnetic flux in an open slot structure. Accordingly, in order to minimize the cogging torque, the iron core or the slot may be removed.

Among the technologies for minimizing cogging torque developed so far, the method of removing the iron core is called the coreless method, and the method of removing the slot is called the slotless method.

The coreless method removes the iron core and winds only with a coil. Although it has the effect of minimizing the cogging torque, it has disadvantages in that the output density and efficiency are lowered due to the limitation of magnetic force transmission. to be.

Although the slotless method uses the iron core as it is, it is a method of winding by configuring a slot on the iron core opposite the rotor.

Recently, methods to minimize cogging torque while increasing the space factor by using the split-core method have been attempted, but there are many problems in durability such as vibration after assembly, and thus it is limitedly used only in some fields.

Accordingly, the present applicant has filed an application with Application No. 10-2020-0062857 (hereinafter, earlier application), and improved the configuration of the earlier application to minimize the cogging torque in various poles and slots to maximize the efficiency of the generator and the motor. We came up with a structure that can minimize the cogging torque by filling it.

Japanese Patent Registration No. 5665362, 2014.12.19. registration

SUMMARY OF THE INVENTION An object of the present invention is to provide a stator structure that minimizes cogging torque and minimizes cogging torque in generators and electric motors of all structures.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A stator structure for minimizing cogging torque according to an embodiment of the present invention for solving the above-described problems includes a stator formed in an annular shape, a rotor positioned coaxially and rotatably disposed on the stator, and a coil wound around the stator It may include a stator tooth formed in a predetermined width and provided with a plurality of protrusions protruding toward the rotor, a slot formed in a space adjacent to the stator tooth, and an insertion member inserted into the slot.

It is formed at each end of the stator teeth, and may include a pole portion having a narrow portion formed to be stepped with a width smaller than the width of the stator teeth.

The pole part may further include an extension part extending from the narrow part toward the rotor, the width of which is gradually greater than that of the narrow part.

The maximum width formed by the end of the extension portion may be equal to or smaller than the width of the stator teeth.

The insertion member may be inserted into a portion of a slot formed by a narrow portion and an extension portion adjacent to each other of the stator teeth.

The insertion member may form a closed slot for closing the entire area projected to the outer circumferential surface of the rotor from the slot formed between the stator teeth adjacent to each other.

The number of the insertion members may be provided in a number corresponding to 1:1 to the number of slots.

It may include a blocking member formed to surround the narrow portion and the expanded portion of any one of the stator teeth of the stator teeth.

The blocking member may be formed to have a trapezoidal cross-section gradually widening toward the rotor, and may have a pair of leg portions bent in a direction adjacent to each other.

The number of the blocking members may be provided in a number corresponding to 1:1 to the number of the stator teeth.

Other specific details of the invention are included in the detailed description and drawings.

As described above, the stator structure for minimizing cogging torque according to an embodiment of the present invention minimizes the cogging torque to minimize torque ripple, vibration, and noise, thereby improving the efficiency of the generator and the electric motor.

In addition, the cogging torque can be minimized regardless of the combination of the number of poles and the number of slots of the motor.

In addition, it is possible to insert the bobbin insertion member at the lower end of the stator teeth by the thickness of the stator, and to minimize the cogging torque by contacting the legs of the adjacent blocking members with each other.

In addition, since the bobbin winding can be coupled to each stator tooth in a completed state, automation is possible, thereby improving productivity.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a plan view of a stator structure for minimizing cogging torque according to a first embodiment of the present invention.
Figure 2 is a perspective view showing a state in which the insertion member of Figure 1 is coupled.
3 is a plan view of a stator structure for minimizing cogging torque according to a second embodiment of the present invention.
4 is a perspective view illustrating a state in which the blocking member of FIG. 3 is coupled.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and those of ordinary skill in the art to which the present invention pertains. It is provided to fully inform those skilled in the art of the scope of the present invention, and the present invention is only defined by the scope of the claims.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural, unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components in addition to the stated components. Like reference numerals refer to like elements throughout, and "and/or" includes each and every combination of one or more of the recited elements. Although "first", "second", etc. are used to describe various elements, these elements are not limited by these terms, of course. These terms are only used to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the spirit of the present invention.

Unless otherwise defined, all terms (including technical and scientific terms) used herein will have the meaning commonly understood by those of ordinary skill in the art to which this invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly specifically defined.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between a component and other components. A spatially relative term should be understood as a term that includes different directions of components during use or operation in addition to the directions shown in the drawings. For example, when a component shown in the drawing is turned over, a component described as “beneath” or “beneath” of another component may be placed “above” of the other component. can Accordingly, the exemplary term “below” may include both directions below and above. Components may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view of a stator structure that minimizes cogging torque according to a first embodiment of the present invention, and FIG. 2 is a perspective view illustrating a state in which the insertion member of FIG. 1 is coupled.

1 and 2, the stator structure for minimizing cogging torque according to the first embodiment of the present invention is a stator 100, a rotor 101, a stator tooth 102, a slot 100a, and an insertion member. (120) may be included.

The stator 100 may be formed in a hollow cylindrical shape. In addition, the stator 100 is disposed on the same axis as the rotor 101, and is disposed in a form surrounding the outer circumference of the rotor 101 to provide a ring-shaped void that is a space spaced apart from the outer circumferential surface of the rotor 101. can be

The stator 100 may be protected by an external housing (not shown), and may be fixed to the housing.

The stator 100 may be arranged such that a plurality of stator teeth 102 on which a coil is wound, and a plurality of slots 100a, which are spaces in which the coil is located, surround the rotor 101 and form a radial shape. .

The stator teeth 102 may be formed to protrude from the inner circumferential surface of the stator 100 toward the central axis C or the rotor 101 in plurality, and a coil may be wound around the stator teeth 102 .

The stator 100 may be arranged to connect each stator tooth 102 as a ring shape. A coil is wound around each stator tooth 102 to generate a magnetic flux when an external power is applied. To this end, a plurality of permanent magnets may be disposed on the rotor 101 as will be described later.

The rotor 101 is a cylindrical member, and a rotating shaft (not shown) is inserted and fixed to the central axis (C), or is formed integrally with the rotating shaft to rotate with respect to an external conventional housing (not shown). can be installed.

A plurality of permanent magnets are installed in the rotor 101, and in particular, in the case of a permanent magnet embedded brushless motor, the permanent magnets are drawn in from the outermost part of the rotor 101 toward the central axis C by a predetermined distance. can be installed.

The permanent magnet has a rectangular cross-section in the transverse direction, and can be referred to as a linear permanent magnet when compared to a permanent magnet having an arc-shaped cross-sectional shape according to the outer circumferential shape of the rotor 101 . A plurality of such permanent magnets may be provided and disposed at equal radial intervals with respect to the rotor 101 .

In addition, instead of the method in which the permanent magnet is attached to the outer circumferential surface of the rotor 101 , the permanent magnet may be embedded inside the rotor 101 .

In addition, an embedded groove (not shown) is provided on the side surface of the rotor 101 so that the permanent magnet is embedded, and the embedded groove may have two embedded grooves arranged in a V-shape or a radial shape.

The permanent magnet is coupled to the rotor 101 and reacts with a coil to which power is applied to provide a driving force for rotating the rotor 101 .

The stator structure for minimizing the cogging torque according to an embodiment of the present invention is an embedded type (IPMSM: Interior Permanent Magnet Synchronous Motor) in which a permanent magnet having a certain curvature is embedded in the inside of the rotor, a cylindrical embedded type, or a radially embedded type. It may include any one structure.

For example, the arrangement structure of the first permanent magnet forming the N pole and the second permanent magnet forming the S pole on the rotor 101 is asymmetric, or the polarity and the S pole forming the N pole on the rotor core The polarities to be formed may be symmetrical to each other.

The permanent magnet is a magnet that preserves a strong magnetization state, and since it stably maintains the magnetism even if it is not supplied with electric energy from the outside, it is coupled with the rotor 101 and reacts with the coil to which power is applied to the rotor 101 can be rotated.

The permanent magnet provided to react with the coil to which power is applied to rotate the rotor 101 and the insertion member 120 to reduce torque ripple when the rotor 101 rotates may be included.

The insertion member 120 may be made of a material similar to that of the stator 100 , and may be coupled between the adjacent stator teeth 102 one by one to fill the gaps between the adjacent stator teeth 102 .

That is, the insertion member 120 has a structure that fills a space for every slot 100a along the inner circumferential surface of the stator 100, and by forming a closed slot, it is possible to reduce the torque ripple and suppress the transmission and noise generation of the motor.

Since the cogging torque is generated because the stator 100 and the slot 100a exist, a technique for minimizing the cogging torque is being studied by removing the stator 100 and the slot.

However, when the stator 100 and the slot 100a are removed, the transmission force of magnetic force is weak, the structure of the stator 100 is weak, the output density and efficiency are reduced, and the durability is deteriorated.

Although the cogging torque is generated due to the stator 100 and the slot 100a, to be precise, the cogging torque is generated because the slot 100a is open.

There is no cogging torque in a closed slot in which the slot 100a is not opened.

Therefore, research for realizing the closed slot structure of the divided core method has been conducted in the meantime, but the divided core method has not been popularized due to various problems such as durability of the divided core fixing device.

Accordingly, in the stator structure for minimizing cogging torque according to the first embodiment of the present invention, the generator and the electric motor are conventionally used in generators and motors. Since the cogging torque is minimized while using the same), most of the disadvantages of the split core can be eliminated.

On the other hand, a typical stator tooth 102 in a generator and an electric motor has a pole part 110 at the end.

The pole part 110 is to prevent the winding from flowing down after winding, and is mostly present in stators used in all generators and motors that do round winding.

If the width d2 of the pole part 110 is formed to be larger than the width d0 of the fixed car teeth 100 , it is impossible to wind the pole part 110 and insert it into the stator teeth 102 .

Recently, methods for removing the pole part 110, inserting the wound bobbin, and fixing the inserted bobbin have been studied for winding automation, but it is not easy to fix the inserted bobbin while sufficiently ensuring durability.

In the stator for minimizing cogging torque according to the first embodiment of the present invention, the length of the insertion member 120 is inserted into the lower part of the stator teeth 102 as much as the thickness of the stator teeth 100 .

The pole part 110 may include a narrow part 111 and an extension part 112 . Here, the width of the stator 102 is formed to be stepped with a width d1 smaller than the minimum width d2 that gradually decreases from the maximum width d0 to the rotor 101 side, so that the width of the narrow portion 111 is stepped. (d1) may be formed smaller than the minimum width (d2) of the stator teeth (102).

The width d2 of the extension 112 may be equal to or smaller than the width d2 of the stator teeth 102 .

The width d1 of the narrow portion 111 and the width d2 of the extended portion 112 secure the insertion groove 100b into which the insertion member 120 can be inserted and at the same time minimize the gap between the slot 100a. It can be designed to the extent possible.

The insertion member 120 may be inserted into each space 100b provided between the adjacent stator teeth 102 . That is, the number of insertion members 120 may be provided to correspond to the number of slots 100a 1:1.

For this reason, it is applicable regardless of the combination of the number of poles and the number of slots, and the cogging torque can be minimized in all poles from 2 poles to multi-poles regardless of the number of poles.

The stator structure for minimizing cogging torque according to the first embodiment of the present invention is implemented as follows.

First, each stator tooth 102 is formed in a linear shape so that a bobbin can be inserted from the inner diameter (outer diameter in case of an outer rotor) of the stator 100, and adjacent pole parts 110 of each stator tooth 100 An insertion groove (100b) provided therebetween is formed to couple the insertion member (120).

The insertion groove 100b may have various shapes, but it is preferable to design a tolerance in advance so that no play is generated so that vibration does not occur after assembling the insertion member 120 .

As described above, by being coupled between adjacent stator teeth 102 per one inserting member 120 , a method of simultaneously fixing two bobbins with one inserting member 120 becomes possible.

3 is a plan view of a stator structure that minimizes cogging torque according to a second embodiment of the present invention, and FIG. 4 is a perspective view illustrating a state in which the blocking member of FIG. 3 is coupled.

Looking at the stator structure for minimizing the cogging torque according to the second embodiment of the present invention, in the case of FIG. 1 , an insertion groove 100b provided between the pawls 110 of the stator teeth 102 adjacent to each other of the stator 100 . ) has a structure in which the insertion member 120 is inserted, while the blocking member 220 surrounding the pole part 110 of the stator tooth 102 of the stator 100 of FIG. 1 is provided. Duplicate descriptions of the components having the same will be omitted.

That is, the stator for minimizing the cogging torque according to the second embodiment of the present invention includes the narrowed portion 111 and the expanded portion 112 of any one of the stator teeth 102 of the stator 100 . It may include a blocking member 220 formed to surround.

The blocking member 220 may have a pair of leg portions 221 that are formed in a trapezoidal shape in which an area is gradually widened toward the rotor 101 and are bent in a direction adjacent to each other.

By attaching the leg portions 221 of the blocking members 220 adjacent to each other, the entire area projected from the outer circumferential surface of the rotor 101 from the slot 100a formed between the stator teeth 102 adjacent to each other is closed. be able to

In other words, the blocking member 220 is configured so that the leg portions 221 of the blocking member 220 adjacent to each other can contact each other so as not to form a gap between the stator teeth 102 adjacent to each other to form a closed slot. can

For this reason, both the stator for minimizing the cogging torque according to the first embodiment of the present invention and the stator structure for minimizing the cogging torque according to the second embodiment of the present invention may have increased durability due to vibration.

In addition, the stator structure for minimizing the cogging torque according to the second embodiment of the present invention can minimize the cogging torque regardless of the combination of the number of poles and the number of slots of the electric motor.

On the other hand, it is known that the combination of the highest number of poles and the number of slots has the lowest cogging torque. Since the cogging torque can be minimized by being combined, the cogging torque can be minimized at any number of poles, from 2-pole to multi-pole, regardless of the number of poles.

Since the number of slots can also minimize cogging torque in various slots, it becomes possible to apply cogging torque minimization technology to small and large generators and motors.

In addition, since the bobbin winding is completed and can be coupled to each stator tooth, automation is possible, thereby improving productivity.

In addition, it is possible to insert the bobbin insertion member into the lower end of the stator teeth by the thickness of the stator, and to minimize the cogging torque by contacting the legs of the adjacent blocking members with each other.

In the above, embodiments of the present invention have been described with reference to the accompanying drawings, but those skilled in the art to which the present invention pertains can realize that the present invention can be embodied in other specific forms without changing the technical spirit or essential features thereof. you will be able to understand Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

100: stator
100a: slot
100b: insertion groove
101: rotor
102: stator teeth
110: pole part
111: narrow part
112: extension
120: insert member
220: blocking member
221: leg

Claims (10)

an annularly formed stator;
a rotor coaxially disposed on the stator and rotatably disposed;
a stator tooth formed with a predetermined width so that a coil is wound around the stator and provided with a plurality of protrusions protruding toward the rotor;
slots formed in mutually adjacent spaces of the stator teeth;
an insertion member inserted into the slot;
A pole part having a narrow portion formed at each end of the stator teeth and formed to be stepped with a width smaller than the width of the stator teeth, and an extended portion extending from the narrow portion toward the rotor, the width of which is gradually greater than that of the narrow portion ; and
A stator structure for minimizing cogging torque, comprising a blocking member configured to surround a narrow portion and an enlarged portion of any one of the stator teeth. delete delete According to claim 1,
A stator structure for minimizing cogging torque, wherein the maximum width formed by the end of the extension is equal to or smaller than the width of the stator teeth. 5. The method of claim 4,
and the insertion member is inserted into a portion of a slot formed by a narrow portion and an enlarged portion adjacent to each other of the stator teeth. 6. The method of claim 5,
The insertion member forms a closed slot for closing the entire area projected to the outer peripheral surface of the rotor from the slot formed between the stator teeth adjacent to each other, the stator structure to minimize the cogging torque. 7. The method of claim 6,
The number of the insertion members is provided in a number corresponding to 1:1 to the number of the slots, the stator structure to minimize the cogging torque. delete According to claim 1,
The blocking member is formed to have a trapezoidal cross-section that is gradually widened toward the rotor, and has a pair of legs bent in a direction adjacent to each other, a stator structure for minimizing cogging torque. 10. The method of claim 9,
The number of the blocking members is provided in a number corresponding to 1:1 to the number of the stator teeth, the stator structure to minimize the cogging torque.

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