JP2003102158A - Brushless dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems wherein there are many components and work man-hours, etc., in a coil terminal processing part in a blushless DC motor for a small fan, in which a motor coil is wound on a bobbin. SOLUTION: An air core toric coil is formed, by regular winding using a self welding wire as a coil material in its winding and is prepared as a coil sub-assembly condition fixing the toric coil on a printed circuit board mounting electrical parts, such as a magneto-electric conversion device and a drive circuit beforehand. An extraction wire of the coil is soldered directly in the printed circuit board. In the motor assembly, the sub-assembly parts mounting the coil is inserted in two sets of the stator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor, and more particularly to a radial air gap type brushless DC motor using magnets magnetized in multiple directions in the circumferential direction.

[0002]

2. Description of the Related Art As a structure of a brushless DC motor for a small fan which is currently used, there are a core type radial air gap type and a non-core type axial air gap type. In the iron core type radial air gap type, a large number of electromagnetic steel plates punched into a predetermined shape having a large number of slots are laminated to insulate a large number of slots, and each slot is provided with a winding wire. Winding is a factor of cost increase.

In the non-iron core type axial air gap type, a plurality of air-core coils are arranged on the same plane, and a flat ring magnet magnetized with multiple poles is opposed to the air-core coil with a gap in the axial direction. The coil does not have an iron core, and therefore the efficiency of the magnetic circuit is low, and it is limited to a fairly small fan.

In order to solve these problems, Japanese Patent Laid-Open No.
No. 1-214759, Japanese Examined Patent Publication No. 7-46894 and Japanese Utility Model Publication No. 61-153486 are proposed. These have a radial air gap shape, but the magnetic flux from the magnet is collected inside the inexpensive one-piece (two-phase parallel winding with an electrical angle of 180 degrees phase difference) circular coil to penetrate the magnetic material. Then, the coil interlinkage magnetic flux is increased to improve the motor characteristics.

FIG. 9 is an exploded perspective view of a motor according to Japanese Examined Patent Publication No. 7-46894, in which a cylindrical rotor yoke 2 made of a magnetic material and a multi-pole magnetized in the rotor yoke 2 are circumferentially magnetized. The magnet 3 and the motor shaft 4 constitute a rotor 1. Further, 5 is a first stator yoke having a plurality of main magnetic poles 13 and a plurality of magnetic pole pieces 21, 23 is a bobbin for winding, 24 is a coil wound on this bobbin 23, and 25 is planted in the bobbin 23. The lead wire of the coil 24 is connected to the terminal 25 and soldered. 6 is a plurality of main magnetic poles 14 and magnetic pole pieces 2
2 is a second stator yoke having two, and cylindrical center yokes 7 that are telescopically fitted to each other to magnetically short-circuit the first and second stator yokes 5 and 6 respectively. Has been formed. Reference numeral 9 is a Hall element which is a magnetoelectric conversion element for detecting the magnetic pole of the magnet, and 11 is a printed wiring board for electrically connecting the Hall element 9 and the terminal 25 to a drive circuit (not shown).

Further, FIG. 10 shows a phase difference of 2 with an electrical angle of 180 degrees.
The two-phase half-wave drive circuit which energizes the coils 24a and 24b alternately is shown. In the figure, 60 is a motor unit, 61 and 62 are transistors operated by signals of motor drive ICs respectively, and 63.
Is a motor drive IC, 64 is a DC power supply, and 65 is an electrical component mounted on a printed wiring board and wired.

In the above-mentioned motor structure, the coil 24 is wound around the bobbin 23, and the terminal lead wire of the coil 24 is twisted and soldered to the terminal 25 embedded in the bobbin 23. The terminals 25 are inserted into the wiring board 11 and soldered to the printed wiring board 11.

[0008]

However, in such a structure, parts cost of the bobbin 23 and the terminal 25 occurs. Further, the work of twisting the lead wire of the coil end and performing the soldering process is complicated, which causes a cost increase.

Further, in the above brushless DC motor,
A large number of IC-shaped drive circuits for driving the two-phase coils 24a, 24b having an electrical angle of 180 degrees and a phase difference of half-wave are required, and the motor coil is also a bifilar winding in which two wires are simultaneously wound. When the bifilar winding is performed on the bobbin, two wires are mixed during winding and the space factor becomes very poor.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a motor structure in which the number of parts is reduced, the coil end work is improved and the cost is significantly reduced, and at the same time the motor characteristics are improved.

[0011]

Brushless DC of the present invention.
The motor includes a rotor attached to a rotating shaft, a ring-shaped magnet attached to the rotor and magnetized in multiple poles in the circumferential direction, and a ring-shaped magnet facing the inner peripheral surface of the magnet with a gap therebetween. Two sets of stator yokes each having a plurality of main magnetic poles extending outward in the radial direction, a center yoke that magnetically short-circuits the central portions of the two sets of stator yokes, an annular coil, and a magnetoelectric conversion element. , Drive circuit,
In a radial gap type brushless DC motor including a printed wiring board, the coil, the magnetoelectric conversion element, and the drive circuit are mounted on the printed wiring board to form a coil section set, and the two sets The main magnetic poles of the stator yoke are arranged so as to be shifted from each other by an electrical angle of 180 degrees, the two coil pairs are sandwiched by the two stator yokes, and the center yoke is arranged at the center of the coil group. It is characterized by

Further, the brushless DC motor of the present invention is
A rotor attached to the rotating shaft, and a ring-shaped magnet attached to the rotor, which is magnetized in the circumferential direction to have multiple poles;
Each of the magnets has a plurality of main magnetic poles, which are opposed to the inner peripheral surface of the magnet via a gap and extend radially outward from the center.
A radial gap including a pair of stator yokes, a center yoke that magnetically short-circuits the central portions of the two pairs of stator yokes, an annular coil, a magnetoelectric conversion element, a drive circuit, and a printed wiring board. Shape brushless DC
In the motor, the stator yoke has a magnetic pole piece that extends in the axial direction from the tip of the main magnetic pole so as to face the inner peripheral surface of the magnet, and the coil, the magnetoelectric conversion element, and the drive element on the printed wiring board. A circuit is mounted to form a coil section set, the main magnetic poles of the two sets of stator yokes are arranged so as to deviate from each other by an electrical angle of 180 degrees, and the outer circumferential side surface of the coil is formed by the magnetic pole pieces of the two sets of stator yokes. It is characterized in that the coil section set is sandwiched so as to cover it, and the center yoke is arranged at the center of the coil section set.

The printed wiring board is characterized in that holes are formed on the printed wiring board to allow the plurality of magnetic pole pieces to pass therethrough.

The coil is formed in two phases by stacking two circularly wound air-core aligned winding coils in which one self-bonding wire having an adhesive coating on the outside of an insulating coating is closely wound and aligned. It is characterized by being driven by a two-phase half-wave with an electrical angle of 180 degrees.

The coil is formed in two phases by an annular air-core aligned winding coil in which two self-bonding wires having an adhesive coating on the outside of an insulating coating are in close contact with each other and aligned and wound, and the electrical angle is 180 degrees. It is characterized by being driven by a two-phase half-wave with a phase difference.

The coil is formed by an annular coil in which one self-bonding wire having an adhesive film on the outside of an insulating film is closely wound and aligned and wound, and the coil is 2n from the inner layer to the outer layer in the coil radial direction. (N is an integer of 1 or more), which is an aligned winding coil in which the center lead-out portion of the winding is provided at the winding end of the n layer or the winding start of the (n + 1) th layer.

A lead wire from the center lead portion of the coil forms two phases with one coil, and an electrical angle of 1
It is characterized by being driven by a two-phase half-wave with a phase difference of 80 degrees.

The printed wiring board is a flexible board.

A plurality of slits extending radially from the center are provided in the center portion of the stator yoke, and the center yoke is formed by bending the center portion in the motor axial direction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings.

In the first embodiment of the present invention, as shown in FIG. 1, a Hall element 9 used as a magnetoelectric conversion element.
And the electronic component 10 for the drive circuit are mounted on the printed wiring board 11, the air-core annular coil 8 having no bobbin is fixed to the printed wiring board 11, and the lead wire of the coil 8 is directly mounted on the printed wiring board 11. Solder and coil assembly 1
2, a stator yoke 6 having two plate-shaped main magnetic poles extending radially outward from the center, and a center yoke 7
And the center yoke 7 is inserted into the coil assembly 12, and the stator yoke 5 having two plate-shaped main magnetic poles extending radially outward from the center is 180 degrees in electrical angle with respect to the stator yoke 6. The motor is constructed by mounting so as to deviate from each other, sandwiching the coil assembly 12 together with the stator yoke 6, and incorporating the rotor 1 including the rotor yoke 2, the multi-pole magnet 3 and the shaft 4.

According to this embodiment of the present invention, since the wiring on the electric circuit is completed by the coil assembly 12 before the motor is assembled, the circuit operation test can be performed before the motor is assembled and the workability is improved. To do. Also, bobbin 2 for coil winding
3 and the terminal 25 are unnecessary, and the cost of parts can be reduced.

In the second embodiment of the present invention, as shown in FIG. 2, stator yokes 5 and 6 in which a center yoke 7 and magnetic pole pieces 21 and 22 are formed, respectively, are used. A hole 26 for penetrating 21 and 22 is provided, and a surface mounting type Hall element 9 is attached to the printed wiring board 11 so as to face the end surface of the magnet 3 at the outer periphery of the hole 26 or at a place without the hole 26. . According to this embodiment, due to the effect of collecting the magnetic flux from the magnet 3, the interlinkage magnetic flux of the coil 8 increases by almost 50%, and as a result, the motor efficiency can be improved.

FIG. 3 shows a third embodiment of the present invention. In this embodiment, two coils 8a are wound in an air-core line by using a self-bonding wire having an adhesive coating on the outside of an insulating coating.
The annular coil 8 is formed by stacking and fixing 8b in the axial direction. In FIG. 3, 41 is a winding end line and 42 is a winding start line. In this embodiment, the coil 8 corresponds to the half-wave drive circuit of FIG.
Use phase winding. According to this embodiment, it is possible to improve the motor efficiency by increasing the space factor by the aligned winding.

FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, two self-bonding wires are used, and the bifilar winding is wound in parallel with the air core by sending them in parallel at the same time. The coil 43 is formed. This coil 43 can also correspond to a half-wave drive circuit as described above.

5 and 6 show a fifth embodiment of the present invention. In this embodiment, the coil 8 is made by adhering one self-bonding wire having an adhesive coating on the outside of the insulating coating to each other. It is assumed that the coil 8 is wound in a line and formed into an annular shape, and that the coil 8 is wound from the inner layer to the outer layer in 2n layers (n is an integer of 1 or more) in the radial direction of the coil.
The center lead-out portion 44 of the winding is formed at the beginning of winding one layer. The arrow in the figure indicates the winding direction.For example, the winding operation is stopped from the inner circumference of the coil in the column direction, the winding operation is stopped at half the number of turns, the wire is pulled out, and the wire is returned to the winding part to continue. By winding the lead wire to a predetermined number of turns, cutting the lead wire, and making an appropriate wiring, the half-wave drive circuit can be handled in the same manner as above.

FIG. 7 shows a sixth embodiment of the present invention. In this embodiment, the printed wiring board is a thin flexible board 45 to increase the coil winding space and increase the space factor. If possible, improve motor efficiency. Also, it can be directly drawn out as a connection line for supplying power to the outside of the motor.

FIG. 8 shows a seventh embodiment of the present invention. In this embodiment, the center yoke 7 is provided in each of the stator yokes 5 and 6 in the embodiment shown in FIG. A plurality of slits 31 extending is provided. According to this embodiment, there is an effect that the eddy current loop that flows in a ring shape around the outer circumference of the center yoke 7 is interrupted, and the eddy current loss is reduced. The center yoke 7 has slits 31 formed in the plate-like portions of the stator yokes 5 and 6,
This part is formed by bending at a right angle.

[0029]

The effects of the brushless DC motor of the present invention are listed below.

1. Winding bobbin 23 and lead wire barbed terminal 2
5 becomes unnecessary, and the material cost can be reduced.

2. Connection of electric parts including the coil can be easily performed on the printed circuit board, and workability is significantly improved.

3. Since the coil is an aligned winding, the space factor is remarkably improved and the motor efficiency is increased as compared with the conventional bifilar winding using a bobbin.

4. Workability is further improved by using a quasi-aligned winding of a bifilar or a single aligned winding coil provided with a center lead-out portion 44.

5. By using a thin printed wiring board 45 such as a flexible board, a winding space can be provided, a space factor is significantly improved, and motor efficiency is increased. Further, it can be directly drawn out as a connection line for supplying power to the outside of the motor.

6. By providing the magnetic pole piece in which the tip of the main magnetic pole of the stator yoke is bent, it is possible to improve the motor efficiency by the effect of collecting the magnetic flux from the magnet.

7. Provide a slit in the center yoke,
A structure that reduces eddy current loss can be realized at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a brushless DC motor of the present invention.

FIG. 2 is an explanatory view of another embodiment of the brushless DC motor of the present invention.

FIG. 3 is an explanatory view of yet another embodiment of the brushless DC motor of the present invention.

FIG. 4 is an explanatory view of yet another embodiment of the brushless DC motor of the present invention.

FIG. 5 is an explanatory view of yet another embodiment of the brushless DC motor of the present invention.

6 is a cross-sectional view of the coil shown in FIG.

FIG. 7 is an explanatory view of yet another embodiment of the brushless DC motor of the present invention.

FIG. 8 is an explanatory view of yet another embodiment of the brushless DC motor of the present invention.

FIG. 9 is an explanatory diagram of a conventional brushless DC motor.

FIG. 10 is an explanatory diagram of a drive circuit of a conventional brushless DC motor.

[Explanation of symbols]

1 rotor 2 rotor yoke 3 magnets 4 motor shaft 5 First stator yoke 6 Second stator yoke 7 Center yoke 8 coils 9 Hall element 10 electrical components 11 Printed wiring board 12 coil assembly 13 main pole 14 main pole 21 pole pieces 22 pole piece 23 Bobbin 24 coils 25 terminals 26 holes 31 slits 41 winding end line 42 winding start line 43 bifilar wound coil 44 Center drawer 45 Flexible substrate 60 Motor part 61 transistor 62 transistor 63 Motor drive IC 64 DC power supply 65 Electrical components

Continued front page    (72) Inventor Yoichi Nagata             433-2 Urinren, Urenren-cho, Naka-gun, Ibaraki Prefecture             Urbo Co., Ltd. in Uren Factory (72) Inventor Masahiro Mimura             433-2 Urinren, Urenren-cho, Naka-gun, Ibaraki Prefecture             Urbo Co., Ltd. in Uren Factory F-term (reference) 5H002 AB06 AE07 AE08                 5H019 BB05 BB15 CC04 DD07 DD10                       EE02 EE07 EE09 EE11                 5H603 AA01 BB01 BB06 BB13 BB17                       CA01 CB13 CC01 CC13 EE01                       FA02                 5H604 AA05 BB01 BB15 CC05 CC19                       QB04 QB12

Claims (9)

[Claims] 1. A rotor attached to a rotary shaft, a ring-shaped magnet attached to the rotor, which is magnetized in multiple poles in the circumferential direction, and is opposed to an inner peripheral surface of the magnet via a gap. Two sets of stator yokes each having a plurality of main magnetic poles extending radially outward from the center, a center yoke that magnetically short-circuits the central portions of the two sets of stator yokes, an annular coil, and a magnetoelectric conversion. In a radial gap type brushless DC motor including an element, a driving circuit, and a printed wiring board, the coil, the magnetoelectric conversion element, and the driving circuit are mounted on the printed wiring board to form a coil assembly. The main magnetic poles of the two sets of stator yokes are arranged so as to deviate from each other by an electrical angle of 180 degrees, and the coil portion set is sandwiched by the two sets of stator yokes.
A brushless DC motor, wherein the center yoke is arranged at the center of the coil assembly. 2. A rotor attached to a rotary shaft, a ring-shaped magnet attached to the rotor, which is magnetized in a circumferential direction with multiple poles, and is opposed to an inner peripheral surface of the magnet with a gap. Two sets of stator yokes each having a plurality of main magnetic poles extending radially outward from the center, a center yoke that magnetically short-circuits the central portions of the two sets of stator yokes, an annular coil, and a magnetoelectric conversion. In a radial gap type brushless DC motor including an element, a drive circuit, and a printed wiring board, the stator yoke has a magnetic pole piece extending axially from the tip of the main magnetic pole so as to face the inner peripheral surface of the magnet. Then, the coil, the magnetoelectric conversion element, and the drive circuit are mounted on the printed wiring board to form a coil section set, and the main magnetic poles of the two sets of stator yokes have an electrical angle of 180 degrees. The coil yokes are arranged so as to be offset from each other, the outer peripheral side surface of the coil is covered by the magnetic pole pieces of the two stator yokes, and the center yoke is arranged at the center of the coil portion set. Brushless DC motor characterized in that 3. The brushless DC motor according to claim 2, wherein holes are formed on the printed wiring board to allow the plurality of magnetic pole pieces to pass therethrough. 4. An annular air-core aligned winding coil in which two self-bonding wires each having an adhesive coating on the outside of an insulating coating are closely wound and aligned and wound in two layers to form two phases 4. The brushless DC motor according to claim 1, 2 or 3, which is driven by a two-phase half-wave with an electrical angle of 180 degrees. 5. The coil is formed in two phases by an annular air-core aligned winding coil in which two self-bonding wires having an adhesive coating on the outside of an insulating coating are closely wound and aligned and wound,
The brushless DC motor according to claim 1, 2 or 3, which is driven by a two-phase half-wave with an electrical angle of 180 degrees. 6. The coil is formed by an annular coil in which one self-bonding wire having an adhesive coating on the outside of an insulating coating is closely wound and aligned and wound, and the coil is formed from an inner layer to an outer layer in a coil radial direction. 2n (n is an integer greater than or equal to 1), and is an aligned winding coil in which the center lead-out portion of the winding is provided at the winding end of the n layer or the winding start of the n + 1 layer. The brushless DC motor according to claim 1, 2 or 3. 7. A lead wire from the center lead-out portion of the coil forms two phases with one coil and is driven by a two-phase half-wave with an electrical angle of 180 degrees. 6. The brushless DC motor according to item 6. 8. The printed wiring board is a flexible board.
Alternatively, the brushless DC motor according to item 7. 9. The center yoke of the stator yoke is provided with a plurality of slits extending radially from the center, and the center yoke is formed by bending the center portion in the axial direction of the motor. 3, 4, 5, 6,
7. The brushless DC motor according to 7 or 8.