KR20070092836A - Pan-cake type brushless dc motor - Google Patents

Abstract

A flat type BLDC(Blushless DC) motor is provided to reduce the loss of a magnetic flux by attaching SMC(Soft Magnetic Composite) plates to magnetic pole pieces of first and second stator yokes. A flat type BLDC motor includes a rotor(110), and first and second stator yokes(120,130). The rotor(110) has a permanent magnet(114). The first and second stator yokes(120,130) are composed of main magnetic poles(122,132) and magnetic pole pieces(124,134) which face each other with a gap. An SMC plate(170) is attached to one side of the magnetic pole piece(124,134) so as to distribute a magnetic flux generated from a coil(140) to the permanent magnet(114) uniformly.

Description

PAN-CAKE TYPE BRUSHLESS DC MOTOR

1 is an exploded perspective view showing a flat BLDC motor according to the prior art,

2 is an exploded perspective view showing a flat BLDC motor of a first embodiment according to the present invention;

3 is a plan view illustrating the first and second stator yokes in FIG. 2;

4 is a partial perspective view showing the flat BLDC motor of the second embodiment according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100: BLDC motor 110: rotor

112: rotor yoke 114: permanent magnet

116: shaft 120, 130: first and second stator yoke

122, 132: main stimulus 124, 134: stimulation fragment

126, 136: center yoke 140: coil

142: terminal 150: wiring board

152: Hall element 160: bearing

170, 270: SMC version

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat BLDC motor, and more particularly, to a flat BLDC motor that reduces torque loss in moving a magnetic flux generated from a coil to a permanent magnet, thereby improving torque output.

In general, a motor is a device that obtains rotational force by converting electrical energy into mechanical energy, and is widely used in home appliances as well as industrial equipment, and is generally divided into a DC motor and an AC motor.

In the DC motor, the brush (brush) is attached to the motor to flow a current at the same time as the current flows to the coil by the contact of the commutator and the brush, but the disadvantage is that the brush is worn. To overcome this drawback, brushless brushless DC (BLDC) motors are widely used.

BLDC motors are widely used in recent years because of their high torque, excellent controllability, and fastness.

The conventional flat BLDC motor will be described with reference to the accompanying drawings.

1 is an exploded perspective view showing a flat BLDC motor according to the prior art. As shown, the flat BLDC motor 1 according to the related art includes a rotor 10, a first stator yoke 20, a second stator yoke 30, and a first stator yoke 30. The coil 40 is positioned between the yoke 20 and the second stator yoke 30, and the wiring board 50 is large.

Here, the rotor 10 penetrates through the rotor yoke 12 in which the magnetic material is formed in a cylindrical shape, the permanent magnet 14 inserted into the rotor yoke 12 and multipole magnetized in the circumferential direction, and the permanent magnet 14. It consists of a shaft 16 inserted into the rotor yoke 12.

The first stator yoke 20 has a plurality of main magnetic poles 22 facing each other, a pole piece 24 in a direction perpendicular to the main magnetic pole 22, and the second steak yoke 30 has a plurality of main magnetic poles ( 32 and a cylindrical center yoke 26, 36 having magnetic pole pieces 34 and superimposed on each other to magnetically short both of them at the centers of the first stator yoke 20 and the second stake yoke 30. Are formed respectively.

The coil 40 is installed between the first stator yoke 20 and the second steak yoke 30, and a terminal 44 extending downward from the coil 40 is provided.

A second stator includes a Hall element 52, which is a magnetoelectric conversion element for detecting magnetic poles of the permanent magnet 14, and a wiring board 50 for electrically wiring the Hall element 52 and the terminal 44 to a drive circuit. It is located at the bottom of the yoke 30. Reference numeral 60 is a bearing.

The flat BLDC motor 1 according to the related art has a magnetic flux generated by supplying a current of a driving circuit of the wiring board 50 to the coil 40 wound through the terminal 42. The rotor 10 including the permanent magnet 14 rotates through this, and at this time, a signal for the magnetic pole of the permanent magnet 14 detected by the hall element 52 installed in the wiring board 50 is transmitted to the wiring board ( It is transmitted to the driving circuit of 50 to supply the power of different polarity to the coil 40 so that the coil 40 has a different magnetic to enable the continuous rotation of the rotor 10.

However, in the flat BLDC motor 1 according to the related art, the first and second stator yokes 20 and 30 are made of steel sheets for bending formation of the magnetic pole pieces 24 and 34, thereby serving as a moving path of the magnetic flux. The thickness of the magnetic pole pieces 24 and 34 is inevitably thin, and thus, the magnetic flux generated from the coil 40 does not properly reach the permanent magnet 14, thereby reducing efficiency and output, and the magnetic pole pieces (24, 34) has a constant curvature in order to maintain a constant void with the permanent magnet (14) for this purpose by the occurrence of the deviation and bending of the magnetic pole (24, 34) from the permanent magnet (14) The flux transmitted to the non-uniform flux had a problem of causing torque ripple as well as torque reduction.

The present invention is to solve the above-mentioned problems, the object of the present invention is to attach the SMC piece to the pole pieces of the first stator yoke and the second stator yoke, to move the magnetic flux generated in the coil to the permanent magnet This provides a flat BLDC motor with reduced losses resulting in improved torque output.

The present invention for realizing the above object is a flat BLDC motor comprising a rotor in which a permanent magnet is fixed, and first and second stator yokes composed of a main magnetic pole and a magnetic pole piece facing each other with a gap in the permanent magnet, The magnetic pole pieces are characterized by providing a flat BLDC motor, characterized in that the SMC plate is attached to one surface so that the magnetic flux generated from the coil is uniformly dispersed in the permanent magnet.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

FIG. 2 is an exploded perspective view showing the flat BLDC motor of the first embodiment according to the present invention, and FIG. 3 is a plan view showing the first and second stator yokes in FIG.

2 and 3, the flat BLDC motor 100 according to the present invention includes a rotor 110, a first stator yoke 120, a second stator yoke 130, and a first stator yoke 130. The coil 140 is positioned between the first stator yoke 120 and the second stator yoke 130, and the wiring board 160 positioned below the second stator yoke 130.

The rotor 110 has a rotor yoke 112 in which a magnetic material is formed in a cylindrical shape, a permanent magnet 114 inserted into the rotor yoke 112 and multi-pole magnetized in the circumferential direction, and the rotor through the permanent magnet 114. It consists of a shaft 116 inserted into the yoke 112.

The coil 140 is provided with a terminal 144, and the wiring board 160 connects the Hall element 152, which is a magnetoelectric conversion element that detects the magnetic pole of the permanent magnet 114, and the Hall element 152 to the driving circuit. Electrical wiring The terminal 144 is located under the second stator yoke 130. Reference numeral 160 is a bearing.

On the other hand, according to a feature of the present invention, the first stator yoke 120 and the second stator yoke 130 including the coil 140 therein and installed as two are stacked are as follows.

 The first stator yoke 120 has a plurality, that is, a "T" shape, wherein the flat runner poles 122 are formed to face substantially in a fan shape, and are bent vertically downwards orthogonally while being integral with the main poles 122. As a result, magnetic pole pieces 124 are formed to concentrate the magnetic flux.

And the SMC plate 170 is attached to the outer surface of the magnetic pole pieces 124 so that the magnetic flux generated from the coil 142 is uniformly dispersed in the permanent magnet 114.

Preferably, the SMC plate 170 has a predetermined thickness and is attached to the same area as the area of the magnetic pole pieces 124, and the attachment method may be made by thermal fusion or the like.

The second stator yoke 130 has a plurality, i.e., opposite inverted " T " shapes, wherein the flat main magnetic poles 132 are substantially fan-shaped, perpendicular to the orthogonal upwards while being integral with the main magnetic poles 132. The magnetic pole pieces 134 are formed to be bent to concentrate the magnetic flux.

As the SMC plate 170 is attached to the magnetic pole pieces 124 of the first stator yoke 120 above, the SMC plate 170 on the outer side of the magnetic pole pieces 134 of the second stator yoke 130. This attachment is installed so that the magnetic flux generated from the coil 142 is uniformly dispersed in the permanent magnet 114.

In addition, preferably, the SMC plate 170 has a predetermined thickness and is attached to the same area as the area of the magnetic pole pieces 134, and the attachment method may be made by thermal fusion or the like.

At the centers of the first stator yoke 120 and the second steak yoke 130, cylindrical center yokes 126 and 136 are formed to overlap each other in order to magnetically short circuit both.

According to FIG. 4 showing the second embodiment, the first stator yoke 220 has a plurality of, i.e., a horizontal main magnetic poles 222 in the form of opposing dates, which are substantially fan-shaped, and are identical to the main magnetic poles 222. FIG. A magnetic pole piece 224 integrally extending in a plane is formed, and the SMC plate 270 is attached to the upper surface of the magnetic pole piece 224 so that the magnetic flux generated from the coil 240 is uniform in the permanent magnet 214. To be dispersed.

In addition, the second stator yoke 230 has an opposite inverse "T" shape, and the flat main magnetic pole 232 is formed in a substantially fan shape, and the "a" character orthogonally upward while being integral with the main magnetic pole 232. The magnetic pole pieces 234 of the shape is bent, the SMC plate 270 is attached to the horizontal upper surface of the magnetic pole pieces 234.

Here, the permanent magnet 214 included in the rotor (not shown) is provided with a gap on the upper surface of the first and second stator yokes 220 and 230.

For reference, the SMC plates 170 and 270 are formed of a soft magnetic composite (also referred to as "SMC") having a three-dimensional shape by a compression process of the soft magnetic powder, and the soft magnetic powder is iron -based) particles, each of which is coated to be electrically insulated. The soft magnetic powder is produced by filling a space including a shape corresponding to the yoke including the tooth in a compression molding machine and then compressing it with a compression member such as a punch.

The operation of the flat BLDC motor having such a structure is performed as follows.

When an operation signal is applied for driving, a current is supplied to the coil 140 wound by the driving circuit of the wiring board 150 to form a magnetic flux. Subsequently, the magnetic flux generated from the coil 140 is transmitted to the permanent magnet 114 through the magnetic pole pieces 124 and 134 of the first and second stator yokes 120 and 130, which are magnetic materials. Will rotate.

On the other hand, the signal for the magnetic pole of the permanent magnet 114 detected by the Hall element 152 on the wiring board 150 is transmitted to the drive circuit of the wiring board 150 so that the coil 140 has a different magnetic Supplying power with different polarities to 140 enables continuous rotation of rotor 110.

At this time, the SMC plate 170 attached to the magnetic pole pieces 124 and 134 of the first and second stator yokes 120 and 130 has solved the problem of the magnetic pole pieces that had to be made thin in the related art. By using the SMC plate 170 of SMC material, the magnetic flux of the coil 140 is uniformly dispersed in the permanent magnet 114, contributing to the improvement of the output of the motor.

Similarly, in the second embodiment, a uniform magnetic flux is generated from the magnetic pole pieces 224 and 234 to which the SMC plate 270 is attached to the permanent magnet 214 positioned on the first and second stator yokes 220 and 230. Can be delivered.

As described above, in the flat BLDC motor of the present invention, by attaching the SMC piece to the magnetic pole pieces of the first stator yoke and the second stator yoke, the loss in moving the magnetic flux generated from the coil to the permanent magnet is reduced and the torque is reduced. This has the effect of improving output.

What has been described above is merely an embodiment for implementing a flat BLDC motor according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, it is beyond the gist of the present invention. Without departing from the scope of the present invention, those skilled in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (3)

In a flat BLDC motor comprising a rotor to which a permanent magnet is fixed, and first and second stator yokes composed of a main magnetic pole and a magnetic pole piece facing each other with a gap in the permanent magnet, The magnetic pole pieces, The flat BLDC motor, characterized in that the SMC plate is attached to one surface of the magnetic pole pieces so that the magnetic flux generated from the coil is uniformly distributed in the permanent magnet. The method of claim 1, The SMC plate is flat BLDC motor, characterized in that attached to have the same area as the pole piece. The method of claim 1, In the first and second stator yoke, Flat BLDC motor, characterized in that the SMC piece is attached to the horizontal upper surface of the pole piece that is bent or extended from the main magnetic pole.

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