KR100647835B1 - Stator core for bldc motor - Google Patents

Abstract

A stator core for a brushless DC motor is provided to reduce a cogging torque by forming slits on an outer surface of the stator core and winding coils on every phase. A stator core for a brushless DC motor includes an inner frame portion(314), a coil winding portion(315), and an outer frame portion(316). The inner frame portion faces a rotor magnet. The coil winding portion is radially elongated from the inner frame portion. The outer frame portion is elongated from an end portion of the coil winding portion. Respective inner frames of stator core segments of the stator core are coupled with other adjacent inner frame portions. A slot(317) is formed between adjacent outer frame portions, which are near to the respective outer frame portions of the stator core segment.

Description

Stator core for brushless direct current motors {STATOR CORE FOR BLDC MOTOR}

1 is a perspective view showing a stator core according to the prior art.

Figure 2a is a perspective view showing one embodiment of a stator core according to the present invention.

FIG. 2B is a cross-sectional view of a brushless DC motor to which the stator core shown in FIG. 2A is applied. FIG.

FIG. 2C is an enlarged partial view of the connecting member of the stator core shown in FIG. 2A.

Figure 3 is a cross-sectional view showing an application example of the connecting member shown in Figure 2c.

Figure 4 is a cross-sectional view showing a brushless DC motor to which a stator core according to another embodiment of the present invention.

Figure 5 is a cross-sectional view showing a brushless DC motor to which a stator core according to another embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

400: brushless DC motor 410: stator core

420: coil 430: rotor magnet

431 shaft 440 permanent magnet

450: case 460: wire contact portion

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core constituting a stator of a motor, and more particularly, to a brushless DC motor (hereinafter referred to as 'BLDC motor') in which a rotor is disposed on an inner circumferential side of the motor. It relates to a core (hereinafter referred to as a 'stator core') used for a stator of a stator.

Conventional DC motors are economical, easy to control, and simple in spite of problems such as vibration and noise generated by mechanical contact between commutator and brush, dust generated by brush wear, and limited life of brushes. It has been widely used due to advantages such as ease of design by structure. As the technology related to BLDC motor has been developed in recent years, the problems caused by the manufacture of the control device and the manufacture of the core are reduced, which enables smooth speed control of the BLDC motor and the production of BLDC motor with excellent efficiency over a wide variable speed range. As a result, BLDC motors have replaced DC motors in various fields, such as compressor motors for air conditioners such as refrigerators and air conditioners, drive motors for drum washing machines, and mobile phones. In particular, a wireless information device such as a mobile phone requires a motor having a simple structure, long life, low noise, and high reliability. Therefore, a BLDC motor of an inner rotor type is currently driven by an automatic folder drive of a mobile phone. It is widely used for automatic functions such as camera driving.

By the way, the conventional BLDC motor has a problem that it is difficult to wind the coil (coil) on the stator core, and therefore, the production of the coil winding jig (difficult) was difficult and complicated, and the efficiency of space utilization in the BLDC motor is not high Since the winding amount of the coil is not enough, there is a problem that does not obtain excellent motor characteristics.

Referring to the drawings, a stator core of a conventional BLDC motor is described as follows.

1 is a perspective view showing a stator core according to the prior art. Referring to FIG. 1, the stator core 110, coil winding 115 and slot 116 are shown.

The stator core 110 according to the related art has a shape in which a plurality of T-shaped coil windings 115 protrude toward the center of the frame portion 114 in the cylindrical frame portion 114. A slot 116, which is a narrow gap, is formed between the ends of each coil winding 115, and a rotor insert 113 is formed at the center of the stator core 110.

In order to install the coil in such a stator core 110, the coil must be wound through the slot 116. Since the slot 116 is formed inside the frame portion 114, the coil is difficult to be wound. There is also a problem that the design of the jig for winding is also complicated and the efficiency of the winding operation is reduced. In addition, there is a problem that the winding alignment of the wound coil is very difficult and the characteristics of the BLDC motor is degraded, and cogging torque, noise, and vibration are caused by the plurality of slots 116.

Therefore, an object of the present invention is to overcome the drawbacks of the prior art as described above, to facilitate the winding of the coil, to effectively utilize the space in the motor to secure the winding amount of the coil, and to reduce the cogging torque phenomenon The present invention provides a stator core for a brushless DC motor.

According to an aspect of the present invention, a plurality of stator cores includes an inner frame portion facing the rotor magnet, a coil winding portion extending radially from the inner frame portion, and an outer frame portion extending from an end portion of the coil winding portion. A brush comprising a segment, wherein each inner frame portion of the stator core segment is magnetically insulated from other adjacent inner frame portions, and a slot is formed between each outer frame portion of the stator core segment and another adjacent outer frame portion A stator core for a lease motor is provided.

Each inner frame portion of the stator core segment is preferably magnetically insulated with an insulating material interposed between other adjacent inner frame portions. In addition, each inner frame portion of the stator core segment may be magnetically insulated from the adjacent inner frame portion by a predetermined distance.

Meanwhile, each inner frame portion of the stator core segment may be magnetically insulated from other adjacent inner frame portions so as to increase magnetoresistance. In this case, each of the inner frame portion of the stator core segment is formed with both ends in a shape that decreases in thickness toward the end, it is preferable that the surface contact or line contact with each other adjacent inner frame portion, respectively.

Hereinafter, a stator core for a BLDC motor according to the present invention will be described in detail with reference to the accompanying drawings. However, the same or corresponding components will be given the same reference numerals and redundant description thereof will be omitted.

Figure 2a is a perspective view showing an embodiment of the stator core according to the present invention, Figure 2b is a cross-sectional view showing a brushless DC motor to which the stator core shown in Figure 2a is applied. 2A and 2B, the stator core 210, the rotor magnet inserting portion 213, the inner frame portion 214, the coil winding 215, the outer frame portion 216, the slot 217, and the coil 220, rotor magnet 230, shaft 231, permanent magnet 235, case 250, and connection member 260 are shown.

The stator core segments 210a, 210b, 210c are each composed of an inner frame portion 214, a coil winding 215, and an outer frame portion 216. A coil winding 215 protrudes from an outer circumferential surface of the inner frame portion 214 having a circular cross section, and protrudes outward from the center point of the arc formed by the inner frame 214. An outer frame portion 216 is formed at each end of the coil winding 215, and the outer frame portion 216 is formed at both sides along the outer circumferential surface of the case 250 of the BLDC motor 200.

The number of stator core segments 210a, 210b, and 210c is equal to the number of phases of the BLDC motor. The stator core segments 210a, 210b, and 210c are coupled to each other by the coupling member 260, which is an insulator, to form the stator core 210. In addition, the stator core is inserted into the rotor magnet insertion portion 213 at the center of the stator core 210 by the respective inner frame portions 214 and the respective coupling members 260 of the stator core segments 210a, 210b, and 210c. To form.

As described above, by forming a separate coil 220 for each phase, an effect of facilitating the winding of the coil 220 can be obtained. A slot 217 is formed between each outer frame portion 216 through which the coil 220 is wound. That is, since the coiling operation of the coil 220 can be performed from the outside through the slot 217, there is no need for a space for a winding tool such as a winding jig to enter therein, and only to the extent that the magnetoresistance increases. Since the slots can be located close to each other, the core surface facing the magnet 235 (that is, the inner circumferential surface of the rotor magnet inserting portion 213) can be increased, thereby increasing torque.

The outer frame part 216 may be formed in contact with the inner circumferential surface of the case 250 or may be supported by the case 250 by way of an elastic body capable of absorbing vibration.

The rotor magnet 230 is formed by magnetizing a cylindrical magnet 235 on the outer circumferential surface of the shaft 231, and may have various polarities such as 2 poles, 4 poles, 6 poles depending on the phase to be applied to the BLDC motor 200. Can be. Phase can also be selected as necessary, such as two-phase, three-phase, BLDC motor 200. A bearing (not shown) is coupled to each end of the shaft 231, and the bearing (not shown) is supported by the case 250. The axial length of the stator core 210 is preferably formed to be the same as the axial length of the permanent magnet 235. The connection length of the connection member 260 is preferably formed to be as short as possible to minimize the insulated gap between each inner frame 214.

Since the stator core 210 has the slot 217 formed on the outside of the stator core 210, the stator core 210 can be easily wound to install the coil 220. ), The coil 220 installation process becomes very simple, and the jig design is simplified even when the winding jig is manufactured. In addition, since the rotor magnet 230 is adjacent to the inner frame portion 214 and not to the slot 217, there is an effect that little cogging torque is generated when the BLDC motor 200 operates. have. As described above, the coil 220 is formed by a winding wound in a space formed by the inner frame portion 214, the coil winding 215, and the outer frame portion 216. The slot 217 of the stator core 210 is formed. ) Is formed on the outer side, so that the winding operation can be performed from the inner side of the coil winding unit 215 to the outer side, so that the windings can be easily aligned and have a large amount of winding, thereby improving the characteristics of the BLDC motor 200. The effect can be obtained.

On the other hand, it is also possible to use a bobbin (not shown) when installing the coil 220 in the stator core 210. In the case of using a bobbin, the bobbin may be horizontally divided to be coupled to each other in the vertical direction of the stator core 210.

FIG. 2C is an enlarged partial view of the connecting member of the stator core shown in FIG. 2A.

Grooves coupled to the projections 211a and 211b formed at the ends of each of the adjacent stator core segments 210a and 210b are formed at both sides of the connection member 260 to couple the stator core segments 210a and 210b. . The connection member 260 may be manufactured using a thermosetting resin or the like, and may be easily mass-produced through a method such as injection.

3 is a cross-sectional view showing an application example of the connecting member shown in FIG. 2C.

Each stator core segment 210a, 210b, 210c formed separately is connected to each other by a connecting portion (A in FIG. 2B) to form a stator core 210. Each end of the adjacent stator core segments 210a, 210b has a protrusion ( 211a and a groove 211a are formed to be coupled to each other, and the stator core segments 210a and 210b adjacent to each other are coupled to each other according to the combination of the protrusion 211a and the groove. Therefore, the protrusion 211a and the groove in which the protrusion 211a is accommodated are preferably formed in a rail shape along the longitudinal direction of the stator core 210, and are connected to each other by vibration by the operation of the BLDC motor (not shown). It is preferable that it is formed so that it may become a little interference fit so that (A) may not separate. The protrusion 211a and the groove are coated with an insulating material to insulate the stator core segments 210a and 210b. On the other hand, as the coupling method between the stator core segments 210a and 210b, various coupling methods such as bonding using the protrusions 211a and the grooves as well as the adhesive may be used.

Each of the stator core segments 210a, 210b, and 210c that are separately formed may be combined with each other after winding a coil (not shown) for each phase, thereby assembling the stator core 210, and thus, winding may be more easily performed. In addition, since the size of the mold (not shown) may be made small in the process of forming the stator core 210, the mold manufacturing cost may be reduced.

4 is a cross-sectional view illustrating a brushless DC motor to which a stator core according to another embodiment of the present invention is applied.

Referring to FIG. 4, the stator core 310, the rotor magnet inserting portion 313, the inner frame portion 314, the coil winding portion 315, the outer frame portion 316, the slot 317, and the coil ( 320, rotor magnet 330, shaft 331, permanent magnet 335, case 350, and spacer 360 are shown.

The stator core segments 310a, 310b, 310c are each composed of an inner frame portion 314, a coil winding 315 and an outer frame portion 316. The coil winding part 315 protrudes from the outer circumferential surface of the inner frame part 314 having a circular cross section, and protrudes outward from the center point of the arc formed by the inner frame part 314. An outer frame portion 316 is formed at each end of the coil winding 315, and the outer frame portion 316 is formed at both sides along the outer circumferential surface of the case 350 of the BLDC motor 300.

The number of stator core segments 310a, 310b, 310c is formed equal to the number of phases of the BLDC motor. Unlike the embodiments of FIGS. 2A and 2B, in this embodiment, each adjacent inner frame portion is adjacent. An end portion 314 is disposed to be spaced apart at a predetermined interval so that the spaced portion 360 is formed. It is desirable to minimize the width of the spacer 360. The magnetoresistance at the end of each inner frame portion 314 is infinite by the spacer 360 formed of the empty space. Thus, each stator core segment 310a, 310b, 310c is magnetically insulated.

This arrangement is such that the outer circumferential surface of each of the outer frame portions 316 of the stator core segments 310a, 310b, 310c is in contact with the inner circumferential surface of the case 350, or the stator core 310 is disposed through an elastic body capable of absorbing vibration. ) Is supported by the case 350 and becomes possible.

The stator core is inserted into the rotor magnet insertion portion 313 at the center of the stator core 310 by the respective inner frame portions 314 and the respective separation portions 360 of the stator core segments 310a, 310b and 310c. Is formed.

As described above, by forming a separate coil 320 for each phase, the effect of winding the coil 320 can be easily obtained. A slot 317 is formed between each of the outer frame portions 316, through which the coil 320 is wound. On the other hand, the rotor magnet 330 is formed by magnetizing the cylindrical permanent magnet 335 on the outer peripheral surface of the shaft 331.

5 is a cross-sectional view showing a brushless DC motor to which a stator core according to another embodiment of the present invention is applied.

Referring to FIG. 5, the stator core 410, the rotor magnet inserting portion 413, the inner frame portion 414, the coil winding portion 415, the outer frame portion 416, the slot 417, and the coil ( 420, the rotor magnet 430, the shaft 431, the permanent magnet 435, the case 450 and the line contact portion 460 are shown, and the configuration except the inner frame portion 414 and the line contact portion 460 is illustrated. Is the same as described in FIG. 4, and a detailed description thereof will be omitted.

The stator core segments 410a, 410b, and 410c are each composed of an inner frame portion 414, a coil winding 415, and an outer frame portion 416.

The number of stator core segments 410a, 410b, and 410c is formed equal to the number of phases of the BLDC motor. Unlike the embodiment of FIG. 4, in this embodiment, each adjacent inner frame part 414 is adjacent. The both ends are formed in a shape that the thickness decreases toward the end to have a sharp pointed tip at both ends, and the ends of each inner frame part 414 are in line contact with the ends of the adjacent inner frame part 414. The line contact portion 460 is formed.

As such, it is preferable to maximize the magnetic resistance of the line contact portion 460 by linearly contacting the end portions of the respective inner frame portions 414, and to form the end portions sharply so that the contact area is minimized even if the surface contact occurs. .

In this embodiment, the ends of the respective inner frame portions 414 are in line contact to minimize the size reduction problem of the magnetoresistance and at the same time prevent the deformation of the rotor magnet insert 413 according to the operation of the BLDC motor 400 to the maximum. There is an advantage to provide a durable and stable structure that can be.

Although the preferred embodiments of the present invention have been described above, those skilled in the art may variously modify and modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that it can be changed.

According to the present invention described above, the stator core is separately formed according to the number of phases and coupled to the connecting member to form a stator core, but the slits are formed on the outer side of the stator core and the coils can be easily wound by winding the coils for each phase. It is possible to obtain the effect of reducing the cogging torque, and to effectively utilize the space in the BLDC motor, thereby increasing the amount of windings and improving the characteristics of the motor. It is easy to achieve the effect of reducing the production cost.

Claims (5)

A plurality of stator core segments including an inner frame portion facing the rotor magnet, a coil winding extending radially from the inner frame portion, and an outer frame portion extending from an end of the coil winding portion, Each inner frame portion of the stator core segment is magnetically insulated from other adjacent inner frame portions, and a slot is formed between each outer frame portion of the stator core segment and the other outer frame portion adjacent thereto. Stator core for DC motors. The method of claim 1, Each inner frame portion of the stator core segment is stator core for a brushless DC motor, characterized in that the insulating material interposed between the other inner frame portion and magnetically insulated. The method of claim 1, And each inner frame portion of the stator core segment is magnetically insulated from another adjacent inner frame portion by a predetermined distance. The method of claim 1, And each inner frame portion of the stator core segment is magnetically insulated from another adjacent inner frame portion to increase magnetic resistance. The method of claim 4, wherein Each inner frame portion of the stator core segment has a both end portion is formed in a shape that decreases in thickness toward the end, the stator core for a brushless DC motor which is in surface contact or line contact with each other adjacent inner frame portion, respectively.

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