KR101707112B1 - Brushless Direct Current Vibrational Motor - Google Patents

Abstract

A brushless direct current vibration motor is provided. Top and bottom sides of an eccentric weight is firmly fixed by arranging and fixing the eccentric weight of a rotor between a back yoke and a permanent magnet. The weight of the eccentric weight can be increased to correspond to a top side of the permanent magnet, and thus contributes to vibration increase. A holding protrusion is provided at top and bottom ends of a bearing coupling unit to prevent a bearing from escaping. In a bracket, a portion for mounting a cogging plate is formed in a groove instead of a hole, to strengthen a supporting force of the entire bracket. Pieces of the cogging plate are connected in one body, so they can be assembled to the bracket easily at once. Optimization of an area of the cogging plate restrains the rotor from rising during starting of the motor, so it is possible to prevent friction noise between the rotor and an upper case. Improvement in a stop speed of a rotating rotor enables mild vibration not to be left. Moreover, it is possible to uniformly maintain a horizontal level of the rotating rotor.

Description

[0001] Brushless Direct Current Vibrating Motor [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration motor, and more particularly, to a brushless direct current (BLDC) vibration motor suitable for application to small electronic devices such as a mobile phone, a portable game machine, an earphone, and a wearable device.

In recent years, the smartphone market has been continuously adding various functions necessary for the user's convenience. In order to install the parts having such functions in a limited space, miniaturization of the parts is required. A mobile communication terminal such as a mobile phone, a pager, or the like employs a vibration motor as a means for informing a user of the reception of a signal. And is used in various fields requiring vibration. For example, a vibration motor is employed as an electronic entertainment apparatus for enhancing a real effect of a game, and recently, it is employed as a means for providing a user notification function to an earphone and various wearable electronic devices worn on a neck. These various electronic devices have become one of the major issues in miniaturization in general, and vibration motors employed in these devices are continuously being demanded for miniaturization.

A vibration motor, which is a typical example of vibration means, generates vibration by converting electrical energy into mechanical energy using the principle of generation of electromagnetic force. 1 and 2 are an exploded perspective view and a cross-sectional view of a BLDC vibration motor 10 proposed by Korean Patent No. 10-1406207.

The BLDC vibration motor 10 includes a rotor 40 that rotates at high speed while being driven, a stator 50 that supports the rotation of the rotor 40 without rotating by itself, And a case 12, 36 for accommodating them.

The case is provided with a space for accommodating the rotor 40 and the stator 50 therein while the upper case 12 covers the upper portion of the substantially disk-shaped bracket 36 provided as a lower case. A shaft fixing portion 38 is formed at the center of the bracket 36 and formed with a shaft coupling hole through which the shaft 26 of the stator 50 is vertically pushed in. A cogging plate 34 is press- Through holes 37 are provided.

The rotor 40 has a magnet 22 attached to a bottom surface of a back yoke 16 and an eccentric weight 20 of a high ratio is attached to the outside of the magnet 22 and the bottom surface of the back yoke 16. [ And the bearing 18 is forcedly press-fitted into the bearing coupling hole 17 provided in the bearing coupling portion 19 in the center of the back yoke 16. The rotor 40 assembled in one body is rotatably coupled to the stator 50.

The stator 50 includes a printed circuit board (PCB) 32, a drive IC 30, a coil 28, a shaft 26, and a cogging plate 34. Specifically, a cogging plate 34 made of a magnetic material is inserted into the through hole 37 provided in the bracket 36. The cogging plate 34 generates a cogging torque in order to improve the rotation torque of the rotor 40 and to improve the performance of the rotor 40 at the time of the initial start of the rotor 40, 22 so that the rotor 40 is stopped at a predetermined position.

One or more coils 28, preferably two to four coils 28 and a drive IC 30 are mounted on a printed circuit board 32 provided at the center of the shaft through hole 39 to generate an electric force. The driving IC 30 has a hall sensor. The printed circuit board 32 is attached to the upper surface of the bracket 36 by means of an adhesive such as an adhesive or an adhesive tape. The printed circuit board 32 adhered to the bracket 36 extends to the outside of the upper case 12 so that the electrode terminal 33 can be easily connected to the outside. The shaft 26 passes through the shaft through hole 39 of the printed circuit board 32 and is inserted and fixed in the shaft coupling hole of the shaft fixing portion 38 provided at the center of the bracket 36. [ Thus, the assembly of the stator 50 is completed.

The bearing 18 of the rotor 40 is extruded into the shaft 26 of the stator 50 and the rotor 40 is rotatably coupled to the stator 50. [ Further, the washer 24 is fitted to the upper and lower portions of the shaft 26, respectively, so that the rotor 40 is forced to rotate within a predetermined height range.

An upper case 12 for protecting the inner stator 50 and the rotor 40 components is assembled with the bracket 36 and the stator 50 and the rotor 40 are housed in the assembled state . At this time, a sliding film or a washer (14) is inserted into the upper case (12) during rotation to prevent friction.

The magnet 22 of the rotor 40 is alternately arranged with the N pole and the S pole along the lower circular surface (i.e., the circular surface on the side of the coil 28) so that the corresponding magnetic field distribution is formed. The driving power of the vibration motor 10 is connected to the printed circuit board 32 through the front end 33. The supplied driving power is supplied to the coils 28 provided inside the driving IC 30 through the driving IC 30. [ At this time, a current is supplied to the coil 28 by using a signal generated by a Hall sensor built in the driving IC 30. [ Each coil 28 through which a current flows forms a magnetic field. Attracting force and repulsive force are simultaneously generated between the magnetic field formed by each coil 28 of the stator 50 and the magnetic field formed by the magnet 22 of the rotor 40. By the interaction of these forces, Is rotated around the shaft (26) of the stator (50). At this time, since the center of gravity of the rotor 50 is eccentric by the eccentric weight 20, the rotor 50 is rotated with trembling. This eccentric rotation is transmitted to the cases 12 and 36, and the vibration motor 10 as a whole vibrates.

However, the conventional BLDC vibration motor 10 has several problems as follows.

First, there is a large structural constraint to make the eccentric weight 20 sufficiently large, and the weak coupling force of the eccentric weight 20 with respect to the back yoke 16 is disadvantageous. Since the eccentric weight 20 is disposed in the space between the outer surface of the magnet 22 and the side wall of the upper case 12, the size of the eccentric weight 20 is also limited to the size of this space. Reducing the radius of the magnet 22 is difficult because it causes a reduction in the rotational force. Unless the size of the upper case 12 is increased, there is a limitation in increasing the weight of the eccentric weight 20 to improve the vibration amount. Consequently, in order to enlarge the eccentric weight 20, it is necessary to increase the size of the upper case 12, which is contrary to the trend of miniaturization of the device using the BLDC vibration motor 10. The force that the eccentric weight 20 makes as a part of the rotor 50 is a bonding force with the back yoke 16. [ The upper surface of the eccentric weight 20 is a joint surface with respect to the back yoke 16. However, the bonding surfaces 20 are narrow and there is a limit in obtaining sufficient bonding force therebetween. A strong centrifugal force is applied to the eccentric weight 20 rotating at a high speed and a bonding force of sufficient magnitude is required to overcome the centrifugal force and maintain a stable bonding state even in the continuous use process. A phenomenon that the eccentric weight 20 is easily detached from the back yoke 16 due to the amount of impact may occur when the electronic device with the vibration motor 10 is dropped.

Secondly, since the cogging plate 34 is inserted into the through hole 39 formed in the bracket 36, the cogging plate 34 may be detached from the bracket 36 during an external impact. A neutral zone is formed between the N pole and the S pole in the magnet 22. When the hall sensor mounted on the driving IC is located in the neutral region, a blowing point is generated and the motor can not operate. The role of the cogging plate 34 installed on the stator is to prevent the blowing point of the motor by stopping the position of the rotor at the correct position so that the N pole or S pole of the rotor magnet 22 is always aligned on the hall sensor. Disengagement of the cogging plate 34 from the bracket 36 prevents the occurrence of a blowing point.

Thirdly, when the cogging plate 34 is installed through the bracket 36, the supporting force that the bracket 36 can provide to the cogging plate 34 may be weakened so that the area of the cogging plate 34 There is a limit in raising. When the area of the cogging plate 34 is small, the attracting force of the cogging plate 34 with the magnet 22 provided on the rotor 40 is also weakened. As a result, a phenomenon in which the rotor 40 is projected upward due to the repulsive force (floating of the rotor 40) is generated at the time of initial startup of the motor 10. The floating rotor 40 can generate noise by colliding with the upper case 12 fastened for protecting internal parts. In order to solve such a noise, a noise-preventing sliding film or a washer 14 has to be additionally installed.

Fourthly, if the area of the cogging plate 34 is small, a time for the rotor 40, which has been rotating while stopping the rotation of the motor 10, to take a long time may become long, and a residual vibration may occur. On the contrary, if the area of the cogging plate 34 is excessively large, a blowing phenomenon may occur. Therefore, it is important to provide a cogging plate 34 having a proper area.

The present invention provides a BLDC vibration motor capable of improving the eccentric weight mounting structure and increasing the weight of the eccentric weight so as to generate a larger vibration amount than the conventional one, .

The present invention is also intended to provide a BLDC vibration motor capable of more stable engagement with an eccentric additional back yoke even when the eccentric additional weight is increased, thereby preventing further eccentricity of the rotor due to drop impact.

Another object of the present invention is to provide a BLDC vibration motor in which the mounting structure of the cogging plate for the bracket is improved to improve the supporting force of the bracket and the stopping speed of the motor is improved so that no residual vibration is left.

The present invention also provides a BLDC vibration motor in which the area of the cogging plate is optimized so that there is no friction with the upper case at the time of starting the motor, thereby eliminating the need to provide a separate anti-vibration means.

According to the embodiments of the present invention, a rotator having an eccentric center of gravity is housed in a case rotatably coupled to a stator, so that the interaction between the magnetic field of the electromagnet formed by the stator and the magnetic field of the permanent magnet of the rotor The brushless vibration motor according to claim 1, wherein the brushless vibration motor is a brushless motor. The case includes a cap-shaped upper case and a bracket having a shaft engagement portion protruding from the center and having a plurality of cogging plate mounting grooves formed around the upper case. The stator includes: a shaft fixed upright to the shaft engaging portion; A cogging plate including a plurality of cogging plate pieces accommodated in the plurality of cogging plate insertion grooves, the plurality of cogging plate pieces generating a cogging torque so that the magnetic pole of the rotor is not positioned at an unfire point; A printed circuit board secured to an upper surface of the bracket accommodating the cogging plate and generating driving power necessary for rotational driving of the rotor using an external power source; A plurality of coils installed on an upper surface of the printed circuit board and serving as an electromagnet while the driving power is supplied; And a washer extruded into the shaft and rotatably supporting the rotor on the shaft engagement portion. Wherein the rotor has a back yoke having a bearing coupling portion provided at the center of a circular horizontal yoke divided into an upper yoke portion and a lower yoke portion with a boundary of an arcuate stepped portion; A bearing press-fitted into the through hole of the bearing coupling portion; A ring-shaped permanent magnet fixed to the lower yoke portion and having N poles and S poles alternately arranged; And a side wall portion extending downward from an outer end of the upper plate portion and surrounding a part of a side wall of the permanent magnet, wherein the upper yoke portion and the permanent magnet are sandwiched between the upper yoke portion and the permanent magnet, 0.0 > eccentric < / RTI >

According to an embodiment of the present invention, the plurality of cogging plate mounting grooves are communicated with each other, and the plurality of cogging plate pieces are connected to each other in a body so as to have a shape corresponding to the plurality of cogging plate mounting grooves, Can be accommodated in the cogging plate mounting groove of the cogging plate.

According to an embodiment of the present invention, the number of the plurality of cogging plate mounting grooves and the number of the plurality of cogging plate pieces may be equal to or half of the number of the permanent magnets.

According to an embodiment of the present invention, the bracket may be formed at an upper end of a sidewall of the cogging plate mounting grooves to prevent the cogging plate from being detached from the cogging plate.

According to an embodiment of the present invention, the thickness of the cogging plate is equal to the depth of the cogging plate mounting groove, so that the upper surface of the bracket at the periphery of the cogging plate forms a flat plane of the same level .

According to an embodiment of the present invention, the thickness of the cogging plate may be a value within a range of 0.03 mm to 0.05 mm.

According to an embodiment of the present invention, the outer diameter of the circular region formed by the whole of the plurality of cogging plate pieces may be the same as the outer diameter of the permanent magnet of the rotor.

According to an embodiment of the present invention, circular first and second stopping protrusions may be provided at upper and lower ends of the through-hole of the bearing coupling portion to prevent the cylindrical bearing from being detached from the outside.

According to an embodiment of the present invention, the rim of the upper surface of the bearing and the rim of the bottom surface may be formed with first and second de-cut portions respectively engaged with the first and second stopping jaws.

According to an embodiment of the present invention, the back yoke includes a lower yoke sidewall portion bent downward from the outer edge of the lower yoke portion and extending downward, wherein a part of the upper surface and a side portion of the lower yoke have a bottom surface And the lower yoke side wall portion, respectively.

According to an embodiment of the present invention, the thickness of the upper plate portion of the eccentric weight is equal to the height of the stepped portion, and the bottom surface of the upper plate portion of the eccentric weight and the bottom surface of the lower yoke portion are at the same level.

According to an embodiment of the present invention, the upper plate portion of the eccentric weight may be joined to the bottom surface of the upper plate yoke portion corresponding to one half of the area of the horizontal yoke.

According to an embodiment of the present invention, the printed circuit board is provided with a drive IC on which a magnetic sensor is mounted and the drive power is supplied to the coil, the stator includes two coils, And may be disposed at a position where the angle between the two coils is half of the angle of the air.

According to an embodiment of the present invention, the angle between the air cores of the two coils may be set to a value equal to a natural multiple of the angle between two adjacent magnetic poles of the permanent magnet.

According to an embodiment of the present invention, the permanent magnet comprises six magnetic poles, and the cogging plate includes six or three pieces of cogging plates. When viewed from the center of the shaft engaging portion, The angle between the center of the neutral region of the permanent magnet adjacent thereto and the center of the neutral region of the permanent magnet in the vicinity of the magnetic sensor is set in a range of 11.1 to 15.6 degrees and in the range of 14.4 to 18.9 degrees .

According to an embodiment of the present invention, the permanent magnet includes four magnetic poles, and the cogging plate includes four or two pieces of cogging plates. When viewed from the center of the shaft engaging portion, The angle between the center of the neutral region of the permanent magnet in the vicinity of the magnetic sensor and the center of the neutral region of the permanent magnet in the vicinity of the magnetic sensor is set in the range of 11.7 to 14.0 degrees, .

According to an embodiment of the present invention, the permanent magnet, the plurality of coils, and the cogging plate may be arranged such that a starting point of a magnetic pole of the permanent magnet coincides with a starting point of an air core of the coil.

According to an embodiment of the present invention, the cogging plate may be arranged in such a manner that the magnetic pole of the permanent magnet can always be aligned on the magnetic sensor when the rotor stops rotating.

According to an embodiment of the present invention, the lower end of the shaft is press-fitted into a shaft engaging hole provided in the shaft engaging portion, and an upper end portion of the shaft is engaged with an inner side of the upper surface of the upper case May be inserted into the groove provided at the center and supported so as not to flow.

According to an embodiment of the present invention, the arc-shaped step may be formed along an arc of 1/4 to 3/4 of a radius of the first half-circle region in the first half-circle region of the horizontal yoke.

According to the present invention, between the eccentric additional back yoke disposed in the rotor and the permanent magnet fixed to the back yoke, both upper and lower surfaces of the eccentric weight can be fixed firmly or indirectly to the back yoke. Even if a vibration motor is used for a long time, stable coupling between the eccentric weight and the back yoke can be maintained. In addition, when a smartphone equipped with a vibration motor falls on the floor, a large impact is applied to the vibration motor due to the weight of the smartphone. The large coupling force according to the coupling structure between the eccentric weight and the back yoke according to the present invention makes it possible to prevent the eccentric weight from being detached from the eccentric additional back yoke even when such strong external impact is applied. Further, since the eccentric weight further includes a portion disposed between the back yoke and the upper surface of the permanent magnet, in addition to the portion disposed on the outer surface of the permanent magnet, the weight of the eccentric weight can be increased further, It is advantageous to do. The diameter of the vibration motor is not increased but the thickness is only slightly increased as compared with the conventional technology. Even with increasing thickness, since the eccentric weight portion to be added is in contact with a portion close to almost half of the back yoke area, a weight increase of a desired and sufficient size can be obtained even with a small thickness.

The bracket and the cogging plate can be punched and attached in a press with a combined mold. In addition, since the cogging plate pieces are connected by a single body, they can be easily mounted on the bracket at the same time. This can contribute to the reduction of manufacturing cost.

In addition, the portion where the cogging plate is mounted on the bracket can be formed into a groove instead of the hole, so that the supporting force of the entire bracket can be enhanced. Further, a plate separation preventing jaw is formed at the upper end of the cogging plate receiving groove of the bracket, so that the cogging plate can be mounted very firmly on the bracket. Therefore, the bracket and its associated cogging plate can withstand heavy impacts and can be used in heavy-weight smart phones and alarm devices.

By optimizing the area of the caulking plate, it is possible to suppress the rise of the rotor at the time of starting the motor, to prevent the friction noise between the rotor and the upper case, and to improve the stopping speed of the rotating rotor. It also makes it possible to keep the horizontal level of the rotating rotor uniform. As a result, it is not necessary to provide separate noise preventing means such as a noise preventing film or a washer.

1 is an exploded perspective view of a conventional BLDC vibration motor,
2 is a cross-sectional view of a conventional BLDC vibration motor,
3 is an exploded perspective view of a BLDC vibration motor according to a preferred embodiment of the present invention,
4 is a cross-sectional view of a BLDC vibration motor according to a preferred embodiment of the present invention,
FIG. 5 is a perspective view showing a state in which a BLDC vibration motor according to a preferred embodiment of the present invention is disassembled into a case, an assembled rotor, and an assembled stator and their assembled state,
6 shows a procedure of assembling a stator according to a preferred embodiment of the present invention,
FIG. 7 illustrates a procedure of assembling a rotor according to a preferred embodiment of the present invention. FIGS. 8 to 10 illustrate a method of mounting a cogging plate on a bracket according to a preferred embodiment of the present invention,
11 is a view for explaining the principle that the permanent magnet is rotated by the interaction between the magnetic field of the permanent magnet and the magnetic field generated by the coil,
12 illustrates the arrangement relationship of a coil, a cogging plate, a Hall element, and a permanent magnet that causes a stationary rotor to be placed at a blowing point when a cogging plate having six permanent magnets and six plate pieces is employed,
FIG. 13 illustrates an optimum arrangement relationship between a coil, a cogging plate, a Hall element, and a permanent magnet when a cogging plate having six permanent magnets and six plate pieces is employed,
Fig. 15 illustrates an optimum arrangement relationship between a coil, a cogging plate, a Hall element, and a permanent magnet when a cogging plate having four permanent magnets and four plate pieces is employed,
Fig. 16 illustrates an optimum arrangement relationship between a coil, a cogging plate, a Hall element, and a permanent magnet when a cogging plate having four pole permanent magnets and two plate pieces is employed.

For the embodiments of the invention disclosed herein, specific structural and functional descriptions are set forth for the purpose of describing an embodiment of the invention only, and it is to be understood that the embodiments of the invention may be practiced in various forms, The present invention should not be construed as limited to the embodiments described in Figs.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprise", "having", and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be construed as meaning consistent with meaning in the context of the relevant art and are not to be construed as ideal or overly formal in meaning unless expressly defined in the present application .

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

3 shows a state in which the components of the BLDC vibration motor 100 according to the preferred embodiment of the present invention are disassembled. Fig. 4 is a sectional view of the BLDC vibration motor 100 assembled with these components. The BLDC vibration motor 100 mainly includes a stator 190, a rotor 240, and a case 110, 260 that protects the two assemblies 190, 240 by incorporating them.

The upper case 260 is shaped like a circular cap and its bottom surface is opened. The upper case 260 includes a circular upper surface 262 and a cylindrical side wall 264 bent perpendicularly at the edge of the upper surface 262 thereof.

The bracket 110 is provided as a kind of lower case including a disc portion 112 covering and covering the bottom surface of the upper case 260 and a protrusion 113 extending in the horizontal direction from one side of the disc portion 112 .

The bracket 110 is engaged with the upper case 260 while covering the open bottom surface of the upper case 260. The upper case 260 may be joined by laser welding or soldering, for example, in a state in which the disc portion 112 of the bracket 110 is covered. At least one latching groove 266 is formed at the lower end of the side wall 264 of the upper case 260. At least one latching protrusion 114 is formed at the edge of the circular plate portion 112 of the bracket 110 do. When the upper case 260 is coupled to the bracket 110 so that the latching jaws 114 are engaged with the latching grooves 266, it is possible to maintain firm engagement with each other with respect to the external force in the rotating direction.

A stator and a rotor to be described later are mounted in the inner coin-shaped accommodating space defined by the upper case 260 and the bracket 110 thus combined. A shaft fixing portion 115 is provided at the center of the disk portion 112 of the bracket 110. The shaft fixing portion 115 has a cylindrical shape protruding upward, and a shaft coupling hole 118 in which a shaft 130 can be press-fitted and fixed is formed at the center thereof. A plurality of cogging plate mounting grooves 116 are formed in the radial direction around the shaft fixing portion 115.

The cogging plate mounting groove 116 is formed in a shape of a groove in which the bottom surface of the cogging plate 120 is set to a depth enough to accommodate the cogging plate 120, . The depth of the cogging plate mounting groove 116 is preferably substantially the same as the thickness of the cogging plate 120 described below. Further, in order to simplify the installation work of the cogging plate, it is preferable that the plurality of the cogging plate mounting grooves 116 are formed to communicate with each other. The figure shows an example in which six cogging plate mounting grooves 116 are formed to be connected to each other around a shaft coupling hole 115 in a radial arrangement at intervals of 60 degrees. Although six cogging plate mounting grooves 116 are shown in the figure, these are only exemplary and may be formed in other numbers. The number of cogging plate mounting grooves 116 is equal to the number of cogging plate pieces 122.

The BLDC vibration motor 100 includes a stator 190 fixedly installed in the case 110, 260. The stator 190 provides a rotating shaft to the rotor 240 and also generates an electromagnetic force capable of rotating the permanent magnet 200 of the rotor 240 by forming an electromagnet with the electric power supplied from an external power source.

The stator 190 includes a cogging plate 120, a shaft 130, a printed circuit board (PCB) 150, a capacitor 160 mounted on an upper surface thereof, a driving IC 170, a plurality of coils 180, And may include a washer 135. It is shown in the figure that two air-core coils 180 are disposed opposite to each other about the shaft 130 and are disposed 180 degrees apart from each other. A larger number of coils 180 may be installed. The driving IC 170 is provided with a magnetic sensor 175 for converting the magnitude of the magnetic flux or magnetic field into an electrical signal. A Hall element capable of measuring the direction or strength of a magnetic field using a Hall effect can be used as the magnetic sensor 175. [ Of course, other types of magnetic sensors may be used.

During the rotation of the rotor 240, the magnetic pole position of the permanent magnet 200 changes when viewed from the stator 190. When the coil 180 of the stator 190 corresponding to the magnetic pole position of the permanent magnet 200 of the rotor 240 is energized, the electromagnetic force acting between the permanent magnets 200 and the electromagnets of the coils 180 rotates in the rotating direction So that the rotor 240 can continue to rotate in one direction. When the magnetic field center of the stator 190 coil coincides with the magnetic field center of the permanent magnet 200 of the rotor 240 while the rotor 240 is stopped, The torque is weak and the initial start-up of the rotor 240 may not be performed. That is, when the magnetic sensor 175 sensing the pole of the magnet is located in the neutral zone between the N pole and the S pole of the permanent magnet 200, the pole of the permanent magnet 200 can not be detected A blowing point of the rotor 240 occurs.

A cogging plate 120 is provided in the bracket 110 to generate a cogging torque or detent torque so that the rotor 240 is not located at a blow- (120) prevents the neutral region of the permanent magnet (200) from overlapping with the magnetic sensor (175).

The cogging plate 120 provided as cogging torque generating means is made of a magnetic material. The cogging plate 120 is made into a pair of cogging plate mounting grooves 116 and is press-fitted into the cogging plate mounting grooves 120. For example, as illustrated in FIG. 3, six cogging plate pieces 122 are connected to each other with a radial arrangement of intervals of 60 degrees, and a through hole 124 is formed at the center thereof to be extruded into the shaft fixing portion 115.

The thickness of the cogging plate 120 is preferably substantially the same as the depth of the cogging plate mounting groove 116. The cogging plate 120 housed in the cogging plate mounting groove 116 and the upper surface of the bracket 110 around the cogging plate 120 form flat planes of the same level. According to an embodiment of the present invention, the thickness of the cogging plate 120 may be set within a range of 0.03 mm to 0.05 mm. If the thickness is thicker than this value, initial vibration of the vibration motor 100 may occur. On the other hand, when the thickness is thinner than the upper limit value, the rotor 240 is displaced upward due to the repulsive force of the rotor 240 during the initial startup of the vibration motor 100, and collides with the upper case 260 to generate noise .

The area of the caulking plate 120 is also important. According to an embodiment of the present invention, the outer diameter of the circular region formed by the entire cogging plate 120 is preferably substantially the same as the outer diameter of the permanent magnet 200 of the rotor 240. Thereby, the cogging plate 120 can form a strong attractive force with the permanent magnet 200 as much as possible.

It is preferable that the number of the plate pieces 122 of the cogging plate 120 is a number corresponding to one to one with the number of poles of the permanent magnet 200 to be described later. One embodiment of the present invention is a case where six cogging plates 120 are formed by using permanent magnets 200 of bi-directional six poles. This increases the attracting force between the cogging plate 120 and the permanent magnets 200, thereby suppressing the rise of the rotor when the vibration motor 100 is initially started. Therefore, it is not necessary to provide the sliding film 14 or the washer installed in the vibration motor 10 according to the related art to prevent the occurrence of the transition caused by the rising of the rotor at the time of initial start-up. The cogging plate piece 122 may be constituted by a half of the number of poles of the permanent magnet 200 as occasion demands.

The shaft 130 has a cylindrical shape with a smooth surface. And the upper end portion thereof is inserted into the shaft groove 262 formed at the inner center of the upper surface 262 of the upper case 260 so as not to flow, .

The PCB 150 includes a wiring circuit part 152 having a shape capable of covering the disc part 112 of the bracket 110 and the cogging plate piece 122 and having a through hole formed in the center part thereof, And a terminal portion 154 for connecting an external power source to the wiring circuit portion 152. The shape of the terminal portion 154 is substantially similar to that of the bracket 110. [ The wiring circuit portion 152 is provided with electric elements such as a driving IC 170 and a capacitor 160 for protecting the driving IC 170 from overvoltage and wiring lines for electrically connecting them are formed. The driving IC 170 receives external power, generates driving power, and controls the supply of the driving power to the coil 180 to control the driving of the rotor 240. PCB 150 may be made of flexible PCB.

The plurality of coils 180 may be mounted on the upper surface of the PCB 150 so as to face the permanent magnets 200 and may be connected to the driving IC 170 to receive driving power therefrom.

The PCB 150 is adhered and fixed to the upper surface of the bracket 110 on which the cogging plate piece 122 is mounted via an adhesive 140 such as an adhesive or an adhesive tape. 3 shows an example in which a double-sided tape is used as the bonding means 140. Fig. The double-sided tape 140 and the PCB 150 are provided with through-holes 156 and 142 through which the shaft 130 can pass.

A ring washer 135 is extruded into the shaft 130 and rests on the upper surface of the shaft fixing portion 115 to rotatably support the bottom surface of the bearing 210 of the rotor 240. The shaft fixing portion 115 protrudes higher than the wiring circuit portion 152 of the PCB 150 so that the washer 135 is not in direct contact with the wiring circuit portion 152. The washer 135 mounted on the upper surface of the shaft fixing portion 115 is rotated in such a state that the washer 135 protrudes higher than other components of the stator 190 such as the coil 180 or the driving IC 170 Support.

Next, the BLDC vibration motor 100 also includes a rotor 240 coupled to the stator 190 rotatably within the case. The rotor 240 is integrally and rigidly coupled to the back yoke 230, the eccentric weight 220, the bearing 210, and the permanent magnet 200.

 Figs. 3 and 4 and Fig. 7 (A) show the structure of the back yoke 230. Fig. The back yoke 230 is positioned at the top of the rotor 240 to block the magnetic flux generated by the permanent magnet 200 from leaking upward and to couple the components constituting the rotor 240 into one body give. The back yoke 230 is preferably made of a magnetic material for effectively shielding the leakage magnetic flux.

 The back yoke 230 includes a cylindrical bearing coupling portion 232 penetrating in the vertical direction and horizontal yokes 233 and 234 coupled to the upper end of the bearing coupling portion 232 and extending in the horizontal direction. The shape of the horizontal yokes 233 and 234 viewed in the axial direction (vertical direction) is substantially circular. A step is formed along a predetermined arc in one half-circle region of the horizontal yokes 233 and 234, and is divided into an upper yoke 233 and a lower yoke 234 with the step as a boundary. The step can be formed along an arc of 1/4 to 3/4 of the radius of the semicircle region. The arc may be semicircular. The height of the step may be substantially equal to the thickness of the upper plate 222 of the eccentric weight 220 to be described later.

The lower yoke 234 may further include a lower yoke sidewall portion 235 extending a predetermined length in a downward axial direction at an edge thereof (see Fig. 7 (A)). The lower yoke sidewall portion 235 is joined to the side surface of the permanent magnet 200 by welding or the like so that the permanent magnet 200 is more strongly bonded to the back yoke 230 (details will be described later). If the lower yoke side wall portion 235 is too short, the coupling force with the side surface of the permanent magnet 200 may be insufficient. Conversely, if the lower yoke side wall portion 235 is excessively long, the weight of the eccentric weight 220 is canceled to weaken the eccentric force. Therefore, it is preferable that the lower yoke side wall portion 235 is formed to have a length covering 1/4 to 3/4 of the side surface of the permanent magnet 200.

A through hole 236 is provided at the center of the bearing coupling portion 232. The center axis of the through hole 236 is parallel to the axial direction of the shaft 130. The bearing 210 is cylindrical. A through hole 212 is formed in the center of the bearing 210 in the axial direction. The upper surface decut portion 214 is formed while extending along the edge of the upper surface of the bearing 21 and the lower surface deck portion 216 is formed while extending around the edge of the lower surface. The bearing 210 is press-fitted into the through-hole 236 of the bearing coupling portion 232 and is coupled to the back yoke 230 so as to rotate integrally.

The upper engaging jaw 237 and the lower engaging jaw 238 are provided at the upper and lower ends of the bearing engaging portion 232 to prevent the bearing 210 pushed into the bearing engaging portion 232 from being displaced in the vertical direction do. The upper latching jaw 237 can be formed through, for example, a pressing process. The upper latching jaw 237 thus formed is circular to cover the entire upper deck portion 214. The lower stopping jaw 238 may be formed by pressing the bearing 210 into the bearing coupling part 232 and then curling the lower end of the bearing coupling part 232 inward. The lower latching jaw 238 also has a circular shape and covers the entire lower surface of the lower surface of the lower surface of the lower surface. The upper surface decut portion 214 of the bearing 210 is caught by the upper stopping jaw 237 so that the bearing 210 can not be moved upward. Further, the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface of the lower surface. The smaller the area of the lower surface of the bearing 210 contacting the washer 135 is, the more frictional loss can be reduced, which is advantageous.

The eccentric weight 220 includes an upper plate portion 222 which is joined to an inner bottom surface inside the upper yoke portion 233 while surrounding a part of the side surface of the bearing coupling portion 232 and a side wall portion 222 extending downward from the edge of the upper plate portion 222 (224). The eccentric weight 220 is preferably made of a high-cost material such as tungsten or an alloy containing the main material. The side wall portion 224 may be in the shape of an angled bar bent in an arc shape. The joining between the upper plate portion 222 and the upper yoke portion 233 can be performed by using various known welding techniques or adhesives, for example. The upper plate portion 222 of the eccentric weight 220 may be formed in a pseudo-horseshoe shape that is joined to approximately half of the area of the circular back yoke 230 to maximize the amount of eccentricity. That is, it is advantageous to maximize the weight of the eccentric weight 220 and the bonding force with the upper yoke portion 233 by making the eccentric weight 220 large so as to cover most of the bottom surface of the upper yoke portion 233.

It is preferable that the bottom surface of the upper plate portion 222 and the inner bottom surface of the lower yoke portion 234 have substantially the same level for stable installation of the permanent magnet 200. [ It is necessary to determine the thickness of the upper plate 222, the step of the lower yoke portion 234, the thickness of the lower yoke portion 234, and the like.

The permanent magnet 200 is ring-shaped, and a plurality of N poles and S poles are alternately arranged in the ring. The permanent magnet 200 is preferably flat at least on the upper surface thereof in order to firmly join the eccentric weight 220. There is a neutral zone 205 having no polarity between adjacent N poles and S poles of the permanent magnet 200 (see FIG. 11). The width of the neutral region 205 can be determined within a range of approximately 0.2 to 0.6 mm. The permanent magnet 200 is extrapolated to the bearing coupling portion 232 such that a part of the upper surface of the eccentric weight 220 is joined to the bottom surface of the upper plate portion 222 and the remaining portion of the upper surface of the eccentric weight 220 is joined to the inner bottom surface of the lower yoke portion 234 . As mentioned above, the bonding may be performed by, for example, a known welding method or a bonding method using an adhesive. Thereby, the permanent magnet 200 can be strongly adhered to the back yoke 230.

The outer surface of the permanent magnet 200 is joined to the lower yoke side wall portion 235. This bonding further strengthens the bonding force between the permanent magnet 200 and the back yoke portion 230. The bonding force between the inner side surface of the sidewall portion 224 of the eccentric weight 220 and the outer surface of the permanent magnet 200 may be enhanced by adding an adhesive such as an adhesive.

Since the eccentric weight 220 according to the present invention has the upper plate 222 more than the eccentric weight 20 according to the prior art, the eccentric weight 220 can be made heavier so that the amount of eccentric vibration can be increased. In addition, not only the upper surface but also the side surfaces of the permanent magnet 200 are directly or indirectly bonded to the back yoke 230, so that the permanent magnet 200 can further strengthen the binding force with respect to the back yoke 230. This also enhances the coupling force of the eccentric weight 220 to the back yoke 230.

In addition, the eccentric weight 20 according to the related art is bonded to only the upper surface of the back yoke 16, and the area of its upper surface is also relatively narrow. The upper plate 222 of the eccentric weight 220 is bonded to the upper yoke 233 in a large area and the upper plate 222 is joined to the upper yoke 230 and the permanent magnet 200, (Strongly coupled to the back yoke 230) so that both surfaces are bonded. Therefore, the eccentric weight 220 according to the present invention can be bonded to the back yoke 230 with a much stronger force than the conventional art, so that the eccentric weight 220 can maintain a stable engagement state without being detached from a large external impact.

5 shows a state before and after the assembled rotor 240 and the assembled stator 190 are housed and assembled in the cases 260 and 110, respectively. As described above, the eccentric weight 220, the permanent magnet 200, and the bearing 210 are firmly coupled to the back yoke 230 to form a body. The eccentric weight 220 is relatively heavier, And a rotor 240 having a plurality of teeth. The bearing 210 of the rotor 240 is rotatably extruded through the through hole 236 into the shaft 130 of the stator 190. The bottom surface of the bearing 210 is placed on the washer 135. The washer 135 and the bearing 210 have a very smooth surface so that friction loss during rotation is minimized. An electromagnetic force that causes the rotor 240 to rotate in one direction is generated by the interaction between the magnetic pole of the electromagnet formed in the coil 180 and the magnetic pole of the permanent magnet 200, thereby rotating the rotor 240 . Since the rotor 240 is eccentric at the time of rotating the shaft 130 as a rotation axis, the rotor 240 rotates with vibration.

6 shows a procedure for assembling the stator 190 to the bracket 110. Fig. 7 shows a sequence of assembling the components of the rotor 240. Fig. FIGS. 8 to 10 illustrate a procedure and a method of assembling the cogging plate 120 on the bracket 110 in more detail.

In order to assemble the stator 190, the bracket 110 and the cogging plate 120 are first prepared. For the manufacture of the stator 190, the brackets 110 necessary for securing the inner parts and securing the shaft 130, the cogging plate 120 are made.

The shaft fixing part 38 is formed at the center of the bracket 36 according to the related art and the shaft fixing hole 38 is formed at the center of the shaft fixing part 38 so that the shaft 26 can be fixed in the vertical direction. A plate through hole 37 is formed in the disc portion of the bracket 36 around the shaft fixing portion 38 so that the cogging plate 34 can be assembled. This inconveniences the cogging plate 34 to be separately assembled to the bracket 36, and the cost is inevitably increased. Further, if the through hole 37 is formed in the bracket 36, the supporting force of the bracket 36 is naturally weakened. If an external impact is applied, the bracket 36 is deformed, so that internal parts are damaged and deformed easily, and damage such as loosening or disengagement of the cogging plate 34 occurs. Further, the stopping speed of the vibration motor 10 is also slowed down, which is a weak point to be applied to a smart touch phone which places importance on the reaction speed.

In order to solve this problem, the embodiment of the present invention forms a cogging plate mounting groove 116 in the bracket 110 and mounts the cogging plate 120 thereon. Figures 8-11 schematically illustrate this process.

In manufacturing the bracket 110, first, the bracket 110 is made of a material that is approximately twice as thick as the thickness of the cogging plate 120, for example, a non-magnetic SUS 304 soft plate. The material plate material is cut into a bracket 110 by a press, for example, and the shaft fixing portion 115 formed with the shaft coupling hole 118 is machined.

The cogging plate mounting groove 116 of the bracket 110 can be formed by forging using a press. The cogging plate 120 can also be made by cutting the material plate into a press. The cogging plate 120 is inserted into the cogging plate built-in groove 116 thus formed (see Fig. 8).

The combination of the cogging plate 120 with respect to the bracket 110 is applicable to the multiple mold method. In other words, the bracket 110 and the cogging plate 120 can be engaged with the two molds at the same time. By doing so, the cost of installing the cogging plate is reduced. Further, in order to improve the supporting force of the bracket 110, a separate through hole through which the cogging plate 120 can be installed is not formed in the bracket 110. Instead, the thickness of the bracket 110 and the cogging plate 120 are made different from each other, and the plate for making the bracket 110 is forged by forging to form the cogging plate mounting groove 116, The cogging plate 120 can be forcedly assembled into the mounting recess 116 as thin as the thickness portion. This process works with two molds in the same press, that is, a complex mold, so that it is not necessary to fix the plate separately, thereby saving cost and stabilizing the quality.

A cogging plate release preventing tuck 119 protruding from the upper end of the sidewall of the cogging plate holding groove 116 of the bracket 110 to the inside of the holding groove 116 after the cogging plate 120 is mounted in the cogging plate holding groove 116, . The cogging plate release preventing tuck 119 can be formed on the entire boundary line of the cogging plate mounting groove 116 by applying a pressing force to the upper end of the bracket 110 in the direction of the arrow. The outer diameter of the shaft fixing portion 115 of the bracket 110 is extended (that is, r ₂ > r ₁ ) so that the inner diameter of the through hole 124 of the cogging plate 120 is forcibly brought into close contact with the inner surface of the through hole 124, So that the plate 120 is not fixed to the shaft fixing portion 115 (see FIG. 9).

Then, the lower end face and the upper end face of the bracket 110 are pressed together at a time so that the cogging plate 120 firmly adheres to the bracket 110 while reducing the projecting height of the lower end face. The upper surface 122 of the cogging plate 120 may be flush with the upper surface of the bracket 110 so that the upper surface 122 of the cogging plate 120 is flush with the upper surface of the bracket 110. [ (See Fig. 10). Whereby the cogging plate 120 is fixed to the bracket 110 more strongly.

According to such a coupling structure of the cogging plate 120 and the bracket 110, there are various advantages as follows. Since the cogging plate 120 has a plurality of plates integrally formed therein, the cogging plate 120 can be easily positioned and fixed to the bracket 110 at a time. When the cogging plate 120 and the bracket 110 are assembled in this manner, the cogging plate 120 is structurally very stable and the cogging plate 120 is not separated from the bracket 110 even when the external impact is strong. The cogging plate 120 includes a large number of plates corresponding to the number of magnetic poles of the permanent magnet 200 to enhance the attracting force of the cogging plate 120 to the permanent magnet 200 have.

The shaft 130 is forcibly press-fitted into the coupling hole 118 of the shaft fixing portion 115 of the fixed bracket 110 to fix the thus prepared cogging plate 120 (FIGS. 6B and 6C ) Reference).

The PCB 150 is fixed to the upper surface of the bracket 110 and the cogging plate 120 using a double-sided tape 140 (see (C) and (D) in FIG. 6).

The coil 180 is attached to the PCB 150 using an adhesive and soldered to the wiring of the wiring circuit part 152 of the PCB 150 (see (E) and (F) of FIG. 6). Thus, external power applied through the terminal portion 154 can be supplied as driving power to the coil 180 via the driving IC 170.

Next, the assembling process of the eccentric rotor 240 is shown in Fig.

First, the back yoke 230 is processed to have a structure as described above. In particular, an upper engagement step 237 is formed at the upper end of the bearing engagement part 232 to prevent the bearing 210 from being separated.

The eccentric weight 220 is coupled to the prepared back yoke 230. The eccentric weight 220 is housed in the bottom surface of the upper yoke portion 233 and fixed thereto using a bonding technique such as laser welding (see FIGS. 7A and 7B).

Then, the cylindrical bearing 210 is forcibly press-fitted into the coupling hole provided in the bearing coupling portion 232 of the back yoke 230 to fix it. In addition, the lower end of the bearing coupling portion 232 is curled to form the lower retaining jaw 238 in order to prevent the bearing 210 from coming off even after the bearing 210 is press-fitted and fixed. The upper stopping jaw 237 and the lower stopping jaw 238 prevent the bearing 230 from being displaced upward or downward (see FIGS. 7B and 7C).

After the bearing is press-fitted, the permanent magnet 200 is fixed to the eccentric weight 220 and the lower yoke portion 234. That is, the permanent magnets 200 are bonded to the bottom surface of the eccentric weight plate portion 222, the bottom surface of the lower yoke portion 234, and the inner surface of the side wall portion 235. These bonding can be performed by, for example, welding or bonding using an adhesive. (Refer to (C) and (D) in FIG. 7), and is bonded to the bottom surface of the back yoke 230 between the side wall portions 235. This completes the assembly of the rotor 240.

The finished stator 190 and the rotor 240 are assembled by extrapolating the bearing 210 of the rotor 240 to the shaft 130 of the stator 190 as shown in FIG. The bearing 210 is rotatably engaged with the shaft 130 and the bottom surface of the bearing 210 is put on the washer 135 of the stator 190. [ Since the bearing 210 rotates with respect to the fixed shaft 130 and the washer 135, it is desirable that these components have a smooth surface with a very low coefficient of friction in order to minimize movement loss due to friction.

Finally, when the upper case 260 is placed on the assembly of the stator 190 and the rotor 240 and the upper case 260 and the bracket 110 are coupled to each other by, for example, laser welding, (See FIG. 5).

The assembly sequence described above is exemplary, and the order of assembly may be changed unless it is an inevitable posterior relationship.

When external power is supplied through the terminal portion 154 of the bracket 150, the driving IC 170 supplies driving power to the coil 180. Thereby, the two coils 180 become an electromagnet while forming a magnetic field. 11, when a current is supplied to the two coils 180 so that the upper polarities of the left coil 180 and the right coil 180 of the shaft fixing portion 115 are the S pole and the N pole, respectively, the permanent magnets 200 It receives a force in the direction of the arrow shown in Fig. As a result, the permanent magnet 200 rotates clockwise. When the permanent magnets 200 are rotated clockwise by 60 degrees, the upper polarities of the left coil 180 and the right coil 180 of the shaft fixing portion 115 are made to be N poles and S poles, respectively, , The permanent magnet 200 receives a force in the same direction as before (i.e., clockwise). The first magnetic field formed by the two coils 180 interacts with the second magnetic field formed by the permanent magnets 200 of the rotor 240 so that the rotor 240 is rotated And generates a rotational force to rotate in the direction. The rotor 240 can rotate at a high speed around the shaft 130 of the stator 190 by the rotational force.

When the supply of the driving power is interrupted, the rotation of the rotor 240 is stopped. In the state where the rotation of the rotor 240 is stopped, the adjacent N pole and S pole (or S pole and N pole) of the permanent magnet 200 are positioned in the left side region and the right side region of the cogging plate piece 122. However, when the magnetic sensor 175 for detecting the magnetic pole of the permanent magnet 200 is located in the neutral region 205 of the permanent magnet 200, the vibration motor 100 can not start. The cogging plate 120 of the stator 190 does not cause the vibration motor 100 to be placed at such a blowing point. An N pole or an S pole that is not a neutral region of the permanent magnet 200 of the rotor 240 is connected to the driving IC (not shown) when the rotor 240 stops rotating, 170). ≪ / RTI > An embodiment for this purpose will be described in more detail.

As a means for generating an electromagnetic force, consideration will be given to the case where two permanent magnets 200 and two coils 180 are used. The six stimuli are arranged at intervals of 60 degrees along the circumferential direction. The two coils 180 of the stator 190 are disposed opposite to each other with respect to the shaft fixing portion 115. The magnetic sensor 175 mounted on the driving IC 170 is disposed at a position where the angle between the two coils 180 is 180 degrees and the magnetic sensor 175 is disposed around the shaft fixing portion 115, (See Figs. 12 and 13).

12 illustrates a case where the rotor 240 of the vibration motor 100 is located at the non-blowing point. 12, when the angle between the center of the coil 180 and the center of the cogging plate piece 122 adjacent thereto is 30 degrees, the magnetic sensor 175 in the driving IC 170 and the closest cogging plate piece 122 Is 0 degrees and the magnetic sensor 175 overlaps the neutral region 205 of the permanent magnet 200. This causes a problem that the vibration motor 100 is placed at the non-tie point.

Fig. 13 shows a design example for avoiding the vibration motor 100 from being put in this state. According to this design example, when the width of the neutral region 205 of the permanent magnet 200 is 4 mm, the angle between the center of the coil 180 and the center of the cogging plate piece 122 is 12.5 degrees can do. In this case, the angle between the center of the neutral region 205 of the magnetic sensor 175 and the permanent magnet 200 may be 17.5 degrees. Here, 17.5 degrees is the value obtained by subtracting 12.5 degrees from 30 degrees which is half of one angle (60 degrees) of the stimulus. According to such a design, the magnetic sensor 175 can move out of the neutral region 205 of the permanent magnet 200 and align with the magnetic pole of the permanent magnet 200 to sense the magnetic pole. At this time, the center of the cogging plate 122 is out of the neutral region 205 of the permanent magnet 200, and the starting point of the magnetic pole coincides with the starting point of the air core of the coil 180. When the vibration motor 100 is started, 200 and the coil 180 is maximized to obtain a large starting torque.

When the area of the caulking plate 120 is narrow, the attracting force of the rotor 240 with respect to the permanent magnet 200 is weakened so that the rotor 240 protrudes upward due to the repulsive force during the initial start of the vibration motor 100, (260) to generate noise. Conventionally, in order to solve such a noise problem, a sliding film or a washer for noise prevention has to be installed. However, according to the present invention, the number of the cogging plate pieces 122 is six, which is equal to the number of poles of the permanent magnet 200, to prevent noise generation problems as described above without installing a noise preventing sliding film or a washer separately. When the number of the cogging plate pieces 122 is sufficiently large, the rotor 240 rotating around the shaft 130 makes the maximum horizontal rotation, which is advantageous in extending the life of the vibration motor 100 and preventing the occurrence of joints.

As shown in FIG. 14, the number of plate pieces 122-1 of the cogging plate 120-1 may be three, which is half of the number of poles of the permanent magnet 200. FIG. The three cogging plate pieces 122-1 are connected to each other with 120 intervals. It is necessary to design the magnetic sensor 175 to be able to sense the magnetic pole of the permanent magnet 200 out of the neutral region 205 of the permanent magnet 200 in order to prevent the permanent magnet 200 from being located at the non- . The angle between the center of the coil 180 and the center of the neutral region 205 of the permanent magnet 200 and the angle between the center of the magnetic sensor 175 and the center of the neutral region 205 of the permanent magnet 200, A large starting torque can be obtained when the angles between the centers of the cogging plate pieces 122-1 are 12.5 degrees and 17.5 degrees as in the case of Fig.

13 and 14, the angle between the air cores of the two coils 180 of the stator can be set to the same value as the natural multiple of the angle between two adjacent magnetic poles of the permanent magnet 200. [ Since the permanent magnet 200 has six magnetic poles and the angle between the poles is 60 degrees, the angle between the coils of the two coils 180 may be 60 degrees or 120 degrees in addition to the illustrated 180 degrees.

On the other hand, as mentioned above, the number of magnetic poles of the permanent magnet 200 is illustrative. The permanent magnet 200-1 having four magnetic poles as illustrated in Figs. 15 and 16 may be employed.

Fig. 15 shows a case in which the number of plate pieces 122-2 of the cogging plate 120-2 is four, which is the same as the number of stimuli. The four pieces of the cogging plate 120-2 are connected to each other with a space of 90 degrees to each other. Since the angle between the four magnetic poles of the permanent magnet 200-1 is 90 degrees, the angle between the air cores of the two coils 180 can be arranged to be the same angle as the natural number of 90 degrees, that is, 90 degrees or 180 degrees . 15 and 16, the two coils 180 are disposed adjacent to each other such that the angle between the two air cores is 90 degrees. The magnetic sensor 175 may be located opposite the center between the two coils 180. [ In this arrangement, the angle between the center of the coil 180 and the center of the neutral region 205 of the permanent magnet 200 adjacent thereto is 12.5 degrees to obtain a large starting torque, and the magnetic sensor 175 and a neutral region 205 may be 32.5 degrees. Here, 32.5 degrees is a value obtained by subtracting 12.5 degrees from 45 degrees which is one half of the angle of one stimulus.

Fig. 16 shows a case where the number of plate pieces 122-2 of the cogging plate 120-2 is composed of two pieces which are half the number of the stimulation. The two coils 180 and the magnetic sensor 175 have the arrangement as shown in FIG. 15, and the two cogging plates 120-2 are connected to each other with an interval of 180 degrees from each other. In this arrangement, the angle between the center of the coil 180 and the neutral region 205 of the permanent magnet 200 adjacent thereto is 12.5 degrees, and the magnetic sensor 175 and the neutral region 205 close thereto A large starting torque can be obtained when the angle between the centers is 32.5 degrees.

Meanwhile, as mentioned above, the size 4 mm of the width w of the neutral region 205 of the permanent magnet 200 is an exemplary value and can be set in the range of 0.2 to 0.6 mm, preferably in the range of 0.2 to 0.5 mm. When the width w of the neutral region 205 is designed to be 0.2 mm in the arrangement as shown in FIG. 13 or 14 employing the permanent magnet 200 having six magnetic poles, the center of the coil 180 The angle between the center of the neutral region 205 of the permanent magnet 200 is 15.6 degrees and the angle between the center of the neutral region 205 of the permanent magnet 200 and the magnetic sensor 175 is 14.4 degrees, Can be obtained. When the width w of the neutral region 205 is designed to be 0.5 mm, the angle between the center of the coil 180 and the center of the neutral region 205 is 11.1 degrees and the magnetic sensor 175 and the permanent When the angle between the centers of the neutral zones 205 of the magnets 200 is 18.9 degrees, a large starting torque can be obtained.

The width w of the neutral region 205 can be designed within a range of 0.2 to 0.5 mm in the arrangement as shown in Fig. 15 or Fig. 16 adopting the permanent magnet 200-1 having four magnetic poles. In this case, the angle between the center of the coil 180 and the center of the neutral region 205 of the permanent magnet 200 adjacent thereto is 11.7 to 14.0 degrees, and the magnetic sensor 175 and the neutral region of the permanent magnet 200 A large starting torque can be obtained when the angle between the centers of the two cams 205 is 12.5 to 33.3 degrees.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. You will understand.

INDUSTRIAL APPLICABILITY The present invention can be applied to the manufacture of a BLDC vibration motor which can be applied to small electronic devices such as mobile phones, portable game machines, earphones, wearable devices, and the like.

100: BLDC vibration motor 110: Bracket
120, 120-1, 120-2: Cogging plate 130: Shaft
135: Washer 140: Double-sided tape
150: printed circuit board (PCB) 160: capacitor
170: drive IC 175: magnetic sensor
180: coil 190: stator
200: permanent magnet 205: neutral area
210: bearing 220: eccentric weight
230: back yoke 240: rotor
260: Case

Claims (20)

The rotor is accommodated in a case rotatably coupled to the stator in such a manner that an eccentric rotor of the center of gravity is rotatably coupled to the rotator by the electromagnetic force generated by the interaction between the magnetic field of the electromagnet formed by the stator and the magnetic field of the permanent magnet of the rotor, A brushless vibration motor for generating vibrations while rotating,
The case includes a cap-shaped upper case and a bracket having a shaft coupling portion protruding from the center and having a plurality of cogging plate mounting grooves formed around the case,
The stator includes: a shaft fixed upright to the shaft engaging portion; A cogging plate including a plurality of cogging plate pieces accommodated in the plurality of cogging plate insertion grooves, the plurality of cogging plate pieces generating a cogging torque so that the magnetic pole of the rotor is not positioned at an unfire point; A printed circuit board secured to an upper surface of the bracket accommodating the cogging plate and generating driving power necessary for rotational driving of the rotor using an external power source; A plurality of coils installed on an upper surface of the printed circuit board and serving as an electromagnet while the driving power is supplied; And a washer extruded into the shaft and positioned above the shaft engagement portion to rotatably support the rotor,
Wherein the rotor has a back yoke having a bearing coupling portion provided at the center of a circular horizontal yoke divided into an upper yoke portion and a lower yoke portion with a boundary of an arcuate stepped portion; A bearing press-fitted into the through hole of the bearing coupling portion; A ring-shaped permanent magnet fixed to the lower yoke portion and having N poles and S poles alternately arranged; And a side wall portion extending downward from an outer end of the upper plate portion and surrounding a part of a side wall of the permanent magnet, wherein the upper yoke portion and the permanent magnet are sandwiched between the upper yoke portion and the permanent magnet, Wherein the eccentric weight includes a plurality of eccentric weights. 2. The cogging plate mounting structure according to claim 1, wherein the plurality of cogging plate mounting grooves communicate with each other, and the plurality of cogging plate pieces are connected to each other in a body so as to have a shape corresponding to the plurality of cogging plate mounting grooves, Wherein the brushless vibration motor can be housed in an interior groove. The brushless vibration motor according to claim 1, wherein the number of the plurality of cogging plate mounting grooves and the number of the plurality of cogging plate pieces is equal to or half of the number of magnetic poles of the permanent magnet. [2] The brushless vibration motor according to claim 1, wherein the bracket further comprises a separation preventing jaw formed at an upper end of a sidewall of the cogging plate recess grooves so as to prevent the cogging plate from being detached. The cogging plate according to claim 1, wherein a thickness of the cogging plate is equal to a depth of the cogging plate mounting groove, and the upper surface of the cogging plate and a periphery of the cogging plate form a flat plane at the same level. Vibration motor. The brushless vibration motor according to claim 1, wherein a thickness of the cogging plate is set within a range of 0.03 mm to 0.05 mm. The brushless vibration motor according to claim 1, wherein an outer diameter of the circular region formed by the whole of the plurality of cogging plate pieces is equal to an outer diameter of the permanent magnet of the rotor. The brushless vibration motor according to claim 1, wherein first and second stopping protrusions are provided at upper and lower ends of the through hole of the bearing coupling portion, respectively, to prevent the cylindrical bearing from being detached from the outside. 9. The brushless reclining apparatus according to claim 8, wherein a first de-cut portion and a second de-cut portion are respectively formed on the rim of the upper surface of the bearing and the rim of the bottom surface to respectively engage the first and second stopping jaws, Vibration motor. [2] The apparatus of claim 1, wherein the back yoke includes a lower yoke sidewall portion extending downward from the outer edge of the lower yoke portion and extending downward, wherein a portion of the upper surface and a side surface portion of the lower yoke portion extend downward from the lower surface of the lower yoke portion, And is supported by being joined to the yoke side wall portions. The brushless vibration motor according to claim 1, wherein the thickness of the upper plate portion of the eccentric weight is equal to the height of the stepped portion, and the bottom surface of the upper plate portion of the eccentric weight and the bottom surface of the lower yoke portion are at the same level. The brushless vibration motor according to claim 1, wherein the upper plate portion of the eccentric weight is joined to a bottom surface of the upper yoke portion corresponding to one half of the area of the horizontal yoke. 2. The magnetic sensor according to claim 1, wherein the printed circuit board is provided with a magnetic sensor and a drive IC for providing the drive power to the coil, wherein the stator includes two coils, Wherein the brushless vibration motor is disposed at a position where the angle between the air and the air is half. 14. The brushless vibration motor according to claim 13, wherein the angle between the air cores of the two coils is set to a value equal to a natural multiple of the angle between two adjacent magnetic poles of the permanent magnet. 15. The method of claim 14, wherein the permanent magnet comprises six magnetic poles, the cogging plate comprising six or three pieces of cogging plates, the center of the coil facing the center of the shaft, Wherein an angle between the centers of the neutral areas of the permanent magnets is set in the range of 11.1 to 15.6 degrees and an angle between the centers of the magnetic sensors and neutral areas of the permanent magnets in the vicinity thereof is set in the range of 14.4 to 18.9 degrees. Leased vibration motor. 15. The method of claim 14, wherein the permanent magnet comprises four magnetic poles, wherein the cogging plate comprises four or two pieces of cogging plates, and when viewed from the center of the shaft engaging portion, Wherein an angle between the centers of the neutral areas of the permanent magnets is set in the range of 11.7 degrees to 14.0 degrees and an angle between the centers of the magnetic sensors and the neutral areas of the permanent magnets close to the neutral sensors is set in the range of 12.5 to 33.3 degrees. Leased vibration motor. The brushless vibration motor according to claim 1, wherein the permanent magnet, the plurality of coils, and the cogging plate are disposed such that a starting point of a magnetic pole of the permanent magnet coincides with a starting point of an air core of the coil. 14. The brushless vibration motor according to claim 13, wherein the cogging plate is arranged in such a manner that the magnetic pole of the permanent magnet can always be aligned on the magnetic sensor when the rotor stops rotating. [2] The apparatus according to claim 1, wherein the lower end of the shaft is press-fitted into a shaft coupling hole provided in the shaft coupling portion, and an upper end of the shaft is fixed to the upper end of the upper case, Is inserted into the groove and is supported so as not to flow. The brushless vibration motor according to claim 1, wherein the arc-shaped stepped portion is formed along an arc of 1/4 to 3/4 of the radius of the first half-circle region in the first half- .

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