KR101671159B1 - Brushless dc vibration motor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BLDC vibration motor, and more particularly, to a BLDC vibration motor in which a metal yoke is prevented from being detached from a back yoke while a top surface of a back yoke is flat without bending,
A BLDC vibration motor according to the present invention is a BLDC vibration motor including a stator, a shaft, a rotor, and a case, wherein the rotor is formed in a disk shape, and an axial coupling portion through which the shaft penetrates is integrally formed A back yoke having a stopper protruding inward from an upper end of the shaft coupling portion; A metal bearing inserted into the shaft coupling portion and tightly coupled to the stopper; A weight coupled to one side of the back yoke to generate eccentric vibration; And a magnet provided on a bottom surface of the back yoke, wherein the back yoke has a flat top surface.

Description

[0001] BLDC VIBRATION MOTOR [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BLDC vibration motor, and more particularly, to a BLDC vibration motor in which a metal yoke is prevented from being detached from a back yoke while a top surface of a back yoke is flat without bending,

Recently, with the development of communication technologies, mobile phones such as smart phones are one of the most widely popularized among the public.

Since the size of such a portable terminal is becoming smaller and smaller, it is easy to carry, and voice and data communication can be performed anytime and anywhere. Therefore, the portable communication terminal has become a new communication device replacing a wired communication device.

Since the portable terminal is capable of communicating in a public place, unlike a general wired telephone, a separate incoming signal such as a vibration mode for notifying only a user in addition to a sound signal such as a bell sound is required.

2. Description of the Related Art In recent years, there has been an increasing demand for high reliability and high reliability as the frequency of use of a vibration mode in a portable terminal increases.

Conventionally, motors for performing the vibration mode have been variously studied and disclosed. For example, a brushless DC (hereinafter referred to as "BLDC") vibration motor will be described with reference to FIG.

Referring to FIG. 1, a BLDC vibration motor 1 includes a case 30, a stator, and a rotor 10.

The case 30 is configured to cover the bracket 21 and the shaft 31 in the form of a cap.

The stator is a non-magnetic material and has a bracket 21 for inserting the shaft 31 at the center thereof, a PCB 23 provided on the upper surface of the bracket 21, At least one winding coil 25 which generates electric charges, and a Hall IC 24 in the form of a chip which functions as a Hall element and a driving IC.

The Hall IC 24 detects the polarity of the magnet 12 to generate an electric signal and determines the current direction of the winding coil 25 according to the polarity of the magnet 12.

The rotor is provided with a magnet 12 having a predetermined number of poles in the back yoke 11 and a weight chain 13 for generating eccentric vibration in rotation, and a metal bearing 32 is also provided. The rotor (10) rotates by an electromagnetic force acting on the stator (30) and is provided in the case (30).

The magnet 12 is configured to interact with an electromagnetic force generated in the winding coil 25 to generate a force such as an attraction force or a repulsive force and to rotate at a predetermined speed by the force.

The metal bearing 32 is press-fitted into the center of the back yoke 11 and is inserted into the shaft 31 to minimize frictional resistance when the rotor rotates.

Further, a slide washer is inserted between the lower end of the metal bearing 32 and the bracket coupling portion of the shaft to minimize frictional resistance when the rotor rotates.

One end of the shaft 31 is inserted into the bracket 21 and the other end of the shaft 31 is fixed between the axes of the case 30 so that the rotor 31 is rotatable.

Referring to FIG. 2, the rotor 10 will be described in more detail. A circular magnet 12 is provided under the back yoke 11. The magnet 12 has alternating polarities every 90 degrees. And the weight 13 is coupled to the outside of the magnet 12. [

Figure 3 shows the rotor in detail. As shown in the figure, the rotor 10 includes a back yoke 11 into which a metal bearing 32 is inserted, an axial coupling portion 11a into which a shaft (metal bearing) is inserted at the center of the back yoke 11, A magnet 12 provided on the bottom surface of the back yoke 11 and a weight 13 provided on the top surface of the back yoke 11.

However, the rotor 10 of the conventional vibration motor has a problem that the metal bearing 32 is detached from the back yoke 11 due to a falling impact or the like.

Also, since the magnet 12 is coupled to the bottom surface of the back yoke 11 within the thickness t1 of the metal bearing 32 and the weight 13 is coupled to the upper surface of the metal bearing 32, 11a can not cover the entire outer circumferential surface of the metal bearing 32. The thickness t2 of the shaft engaging portion 11a is greater than the thickness t1 of the metal bearing 32 in order to provide the space G to be coupled with the weight 13 on the upper surface of the back yoke 11. [ It is inevitably formed small (t2 < t1). This causes the bonding strength between the metal bearing 32 and the shaft coupling portion 11a to be lowered.

To solve this problem, improved patents for rotors have been disclosed. Referring to FIGS. 4 and 5, it can be seen that a stopper 151 protruding inward is formed at the upper end of the shaft coupling part 150 formed in the back yoke 110. In addition, a groove 142 is formed in the upper end of the metal bearing 140 so as to be fitted to the stopper 151. Therefore, the stopper 151 is shaped into the groove 142 so that the metal bearing 150 is not separated from the back yoke 110.

The back yoke 110 has an inclined portion 110a extending obliquely outward from the upper end of the shaft coupling portion 150 to form the stopper 151 and the magnet 120 and the weight 130 A flat plate portion 110b to be joined is formed. The magnet 120 is provided on the bottom surface of the flat plate portion 110b and the weight 130 is attached to the top surface of the flat plate portion 110b and extends vertically.

The back yoke 110 and the shaft coupling portion 150 are integrally formed. The back yoke 110 is connected to the upper end of the shaft coupling portion 150 and is formed to be stepped downward. The reason for this is to provide the engagement space G of the weight 130. In other words, the weight 130 can be provided within the thickness t1 of the shaft coupling portion 150, which makes it possible to reduce the thickness and improve the coupling strength.

The back yoke thus improved has a side surface which is insufficient for thinning by the inclined portion 110a.

6, a circuit board made of an FPCB (Flexible Printed Circuit Board) is adhered and fixed to the upper surface of the bracket 21, and winding coils 25A and 25B and a hole And an IC 24 is mounted.

The cogging plate 22 serves to stop the rotor at a predetermined position, and is formed of a pair of ferromagnetic pieces and is coupled to one side of the bracket 21.

On the other hand, in order to improve the characteristics and efficiency of the vibration motor, much research has been conducted on the arrangement of the stator, in particular, the winding coils.

Fig. 7 shows another conventional stator 200. In comparison with the stator 20 shown in Fig. 6, two winding coils 215A and 215B are provided on the upper surface of the bracket 211, It can be seen that the pair of winding coils 215A and 215B face each other with the shaft 231 therebetween.

It is preferable that at least two winding coils 25A, 25B, 215A, and 215B are provided on the upper surface of the bracket like the stator 20 and 200 shown in Figs. 6 and 7 in terms of characteristics and efficiency of the vibration motor. Excellence was confirmed experimentally. However, if a plurality of winding coils 25A, 25B, 215A, and 215B are provided in this way, there is a problem that parts are increased and the structure of the vibration motor is complicated, resulting in poor productivity and cost increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a BLDC vibration motor in which a top surface of a back yoke is flatly formed without bending while preventing a metal bearing from being separated from a back yoke.

Another object of the present invention is to provide a BLDC vibration motor in which a weight is provided on the bottom surface of the back yoke to reduce the thickness of the rotor.

Another object of the present invention is to provide a BLDC vibration motor which has one winding coil and in which the shaft is positioned on the inner diameter of the winding coil to exhibit vibration motor characteristics and efficiency equal to or higher than those using two winding coils .

In order to solve the above technical problems, a BLDC vibration motor according to the present invention is a BLDC vibration motor including a stator, a shaft, a rotor, and a case, wherein the rotor is formed in a disk shape, And a stopper protruding inwardly from an upper end of the shaft coupling portion; A metal bearing inserted into the shaft coupling portion and tightly coupled to the stopper; A weight coupled to one side of the back yoke to generate eccentric vibration; And a magnet provided on a bottom surface of the back yoke, wherein the back yoke has a flat top surface.

It is preferable that the weight is provided on the bottom surface of the back yoke.

The stator further includes: a bracket having a shaft at a center thereof; A PCB mounted on the bracket; And a winding coil provided on an upper surface of the PCB or the bracket to generate an electromagnetic force and the shaft is positioned on an inner diameter of the PCB or the bracket, wherein the pair of long sides facing each other with the shaft therebetween, And a pair of short sides which connect the parts and face each other.

Preferably, the outer diameter of the winding coil is equal to or smaller than the outer diameter of the magnet of the rotor, and the inner diameter of the winding coil is equal to or larger than the outer diameter of the magnet of the rotor.

It is also preferable that the long side portion is formed so as to approach the shaft toward the center.

According to the present invention, there is an effect that the top surface of the back yoke is formed flat without bending, while preventing the metal bearing from being separated from the back yoke.

Further, the weight is provided on the bottom surface of the back yoke, so that the thickness of the rotor is also thin.

Further, since the shaft is located on the inner diameter of the winding coil, it is possible to exhibit the characteristics and efficiency of the vibration motor equal to or higher than that using two winding coils.

In addition, the number of parts is reduced, the structure of the vibration motor is simplified, and the productivity is improved and the cost is lowered.

1 is a sectional view of a conventional BLCD vibration motor.
Fig. 2 and Fig. 3 show the rotor of the vibration motor shown in Fig.
Figures 4 and 5 show a conventional improved rotor.
6 and 7 show the stator of the vibration motor shown in Fig.
8 shows an embodiment of a BLDC vibration motor according to the present invention.
9 and 10 show a rotor of a BLDC vibration motor according to the present invention.
11 and 12 show a stator of a BLDC vibration motor according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a configuration and an operation of an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 8, the BLDC vibration motor 300 includes a case 330, a stator, and a rotor 310.

The rotor 310 according to the present invention will be described in detail with reference to Figs. 9 and 10. Fig.

As shown, the rotor 310 according to the present invention includes a back yoke 311, a metal bearing 332, a weight 313, and a magnet 312.

The back yoke 311 is formed in a disc shape, and an axial coupling portion 311a through which the shaft 331 passes is formed integrally with the back yoke 311. A stopper 311b protruding inward is formed at an upper end of the shaft coupling portion 311a. A groove 332b is formed in the metal bearing 332 so that the stopper 311b is shaped. That is, the stopper 311b is provided to prevent the metal bearing 332 from being separated by the drop impact.

Particularly, it can be seen that the back yoke 311 according to the present invention is formed in a flat plate shape without being bent. This prevents the back yoke 311 from being thinned because the inclined portion 110a is not formed unlike the case of FIG. 4, although the stopper 311b for preventing the metal bearing 332 from being separated is formed.

Furthermore, the weight 313 is provided on the bottom surface of the back yoke 311, not on the top surface thereof, so that the thickness of the rotor 310 can be made thinner. However, according to the present invention, the weight may be coupled to the upper surface of the back yoke 311, or may be coupled to the upper surface and the side surface in an 'a' shape (see 130 'in FIG. 4). In this case, the thickness of the rotor is increased.

For reference, the weight is a known element coupled to either side of the back yoke to generate eccentric vibration.

The magnet 312 is provided on the bottom surface of the back yoke 311.

11, the stator of the embodiment of the present invention includes a bracket 321, a winding coil 324, a PCB, and a Hall IC 323.

As shown in the figure, one winding coil 324 is wound on the upper portion of the bracket 321 which is a non-magnetic body.

In the present embodiment, a single winding coil 324 is provided on the upper surface of the bracket 321. In particular, a shaft 331 inserted into the center of the bracket 321 and a metal bearing 332 are located. In other words, the winding coil 324 is disposed so that the shaft 331 is positioned at the inner diameter of the winding coil 324. [

The winding coils 324 include a pair of long side portions 324A facing each other with the shaft 331 as a center. In this embodiment, the pair of long side portions 324A are wound in parallel.

A pair of short side portions 324B connecting the pair of long side portions 324A and facing each other is formed so that the winding coil 324 is formed symmetrically with respect to the shaft 331 as a center.

Also, in the embodiment 320 of the stator, a pair of cogging plates 322 are coupled to the bracket 321, which is a non-magnetic body, as in the conventional art. The cogging plate 322 is a ferromagnetic piece.

Further, since the PCB and the Hall IC 323 are typical components, detailed description is omitted.

The outer diameter d2 of the winding coil 324 on the side of the long side portion 324A is formed to be smaller than the outer diameter d3 of the magnet 312 when the stator 320 is coupled to the rotor, . That is, the distance d2 between the outermost lines of the pair of long side portions 324A is smaller than the outer diameter d3 of the magnet 312 (d2 <d3). The stator 320 according to the present invention allows the outer diameter d2 of the long side portion to be in the same range (d2 = d3) as the outer diameter d3 of the magnet, but it is not preferable that the stator 320 has a larger diameter (d2> d3) . This is because the outer diameter d2 of the long side portion 324A side is within the range of the outer diameter d3 of the magnet 312 in terms of vibration motor characteristics and efficiency.

Further, the inside diameter d1 of the winding coil 324 should be larger than the outside diameter of the shaft 331, but it is advantageous to increase the number of windings as small as possible. As the number of turns increases, the consumption current can be lowered and the efficiency of the vibration motor can be improved. The winding coil 324 may be wound as close to the shaft 331 as possible.

The inner diameter d4 of the winding coil 324 at the side of the short side portion 324B is equal to the outer diameter d3 of the magnet 312 (d4 = d3). That is, the distance d4 between the innermost lines of the pair of short sides 324B is equal to the outer diameter d3 of the magnet 312 (d4 = d3). This is because the inner diameter d4 of the short side portion 324B side is equal to or larger than the outer diameter d3 of the magnet 312 (d4> d3) (d4> d3) . However, it is disadvantageous in terms of the vibration motor torque in some cases. However, in order to reduce the size of the appearance of the vibration motor, the inner diameter d4 of the short side portion 324B is made smaller than the outer diameter d3 of the magnet 312 d3) is also possible.

Fig. 12 shows a second embodiment 420 of the stator according to the present invention. As shown in the figure, the second embodiment 420 of the stator has a winding coil 424 on the upper surface of the bracket 421, and the shaft 431 is located on the inner diameter of the winding coil 424 Is the same as the stator 320 shown in Fig. However, unlike the stator 320 of FIG. 11, the stator is not a straight line in which a pair of long side portions 424A facing the shaft 431 are parallel to each other.

More specifically, the long side portion 424A is formed so as to approach the shaft 431 toward the center. In other words, in the second embodiment 420 of the stator, the width d5 of the center of the long side portion 424A is formed to be smaller than the width d6 of the end portion of the long side portion 424A (d5 <d6). Therefore, the long side portion 424A is formed in a wedge shape.

300: BLDC vibration motor
310: Rotor
311: Back yoke
312: Magnet
313: Weight
320:
321: Bracket
322: Cogging plate
323: Hall IC
324: Winding coil

Claims (5)

In a BLDC vibration motor including a stator, a shaft, a rotor, and a case,
The rotor may include:
A back yoke formed in a disk shape and integrally formed with a shaft coupling portion through which the shaft penetrates, and a stopper protruding inward from an upper end of the shaft coupling portion;
A metal bearing inserted into the shaft coupling portion and tightly coupled to the stopper;
A weight coupled to one side of the back yoke to generate eccentric vibration; And
And a magnet provided on a bottom surface of the back yoke,
The back yoke has a flat upper surface,
The stator includes:
A bracket having a shaft at its center;
A PCB mounted on the bracket; And
And a winding coil provided on an upper surface of the PCB or the bracket to generate an electromagnetic force,
Wherein the winding coils comprise a pair of long side portions facing each other with the shaft therebetween, and a pair of short side portions connecting the pair of long side portions and facing each other.
The method according to claim 1,
And the weight is provided on the bottom surface of the back yoke.
delete The method according to claim 1,
The outer diameter of the winding coil is equal to or smaller than the outer diameter of the magnet of the rotor,
Wherein the winding coil has an inner diameter on the side of the short side equal to or larger than an outer diameter of the magnet of the rotor.
5. The method of claim 4,
And the long side portion is formed to be closer to the shaft toward the center.

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