JPH1056766A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless motor whose driving torque is increased more. SOLUTION: A brushless motor is provided with a stator 3 to which a printed-circuit board 1, on which a coil-wound winding part 5 is mounted, is attached and which comprises a frame 2, with a rotary shaft 7 which is fixed to the frame 2 so as to be freely rotatable, with a disk-shaped case 8 to which a rotor 4 is fixed and with the rotor 4 which is fixed to the case 8, which is installed opposite to the winding part 5 and which comprises a ring-shaped main magnet 9. In the brushless motor, the main magnet 9 is arranged near the outer circumference of the disk-shaped case 8, and a generated driving torque is made larger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor mounted on, for example, a drive device for a flexible disk (FD) for rotating and driving the flexible disk. The present invention relates to a brushless motor in which a frequency signal detection pattern for detecting a rotation speed (rotation speed) of a motor is formed on a mounted printed wiring board.

[0002]

2. Description of the Related Art In recent years, electronic devices such as portable AV electronic devices such as a headphone stereo and a camera-integrated VTR, and F
Development and miniaturization of stationary electronic devices such as DD (flexible disk drive) and CD (compact disk) players have become the focus of development.

A bottleneck in reducing the size and thickness of these electronic devices is the size of the motor. Conventionally, in order to reduce the thickness of the motor, for example, a flat brushless DC motor configured by a disk-shaped stator around which a coil is wound and a rotor to which a magnet is attached is employed. I have.

[Overview of Conventional Brushless Motor] (Structure and Operation) There are mainly two types of flat type brushless DC motors. One is an arrangement of a drive coil and a rotor magnet (a rotor drive magnet). Is a radial gap type (also called “outer rotor”; radially opposed type), which is arranged in the circumferential direction, and the other is an axial gap type (plane-facing type), which is arranged facing the plane. There is. When comparing the two, there are advantages and disadvantages, respectively, but the axial gap method is superior in terms of thickness reduction.

FIG. 7 is a sectional view of a main part of a conventional flat brushless DC motor according to the axial gap system. In FIG. 7, since the configuration is line-symmetric with respect to the center of rotation, only the right half is shown in detail in the drawing. As shown, the motor includes a stator 103 fixed to a frame 102 on which a printed wiring board 101 is mounted.
And a rotator 104 disposed close to the printed wiring board 101 and rotatable with respect to the frame 102. Reference numeral 112 represents the head 102 when it has moved to the innermost circumference.

The stator 103 mainly includes a frame 102 having a through hole in the center and a printed wiring board 101. The printed wiring board 101 has a plurality of windings on which a stator winding is wound. The unit (drive coil) 105 is mounted, for example, radially with respect to the center of rotation when viewed from above the motor. A rotating shaft (shaft) 107 is rotatably inserted into the through hole of the frame 102.

The rotor 104 includes a metal case 108 fixed to a rotating shaft 107, and a ring-shaped driving magnet (main magnet) fixed to the inner peripheral wall of the case 108 so as to face the stator 103. ) 109. The case 108 is provided with a speed detecting magnet (hereinafter, referred to as “frequency signal generating magnet” or simply “FG magnet”) 110 extending so as to form a flange on the outer peripheral edge.

Although the main magnet 109 is not shown, N, S, N, S,... Magnetic poles are magnetized at a predetermined pitch in the circumferential direction, and the FG magnet 110 is the main magnet 1.
The magnetic poles N, S, N, S,... Are magnetized at equal intervals in the circumferential direction at a pitch finer than the magnetization pitch of 09.

The FG magnet 1 of the rotor 104
As shown in FIG. 7, a comb-shaped or wavy rotational speed detecting pattern (hereinafter referred to as a “frequency signal generating pattern”, or simply “FG Pattern.)
111 is formed along the outer circumference of the circle formed by the main magnet 109. Both terminals 1 of this FG pattern 111
11a and 111b are drawn out in a state of being close to each other and are formed on the printed wiring board 101 as frequency signal extraction terminals (pads).

In such a configuration, when a drive current is applied to the drive coil 106 of the stator 103, the rotor 10
4 and the drive coil 106
, A rotational force is applied to the rotor 104, and the rotor 104 rotates around the center of rotation.

When the rotor 104 rotates, the FG magnet 110 moves relatively to the FG pattern 111, and both terminals 111a and 111a of the FG pattern 111 are moved.
b, a signal (hereinafter simply referred to as “FG signal”) SFG having a frequency proportional to the rotation speed of the rotor 104 is generated, and the rotation speed of the brushless DC motor can be controlled using the FG signal SFG. It becomes possible.

(FG pattern) Here, the conventional FG pattern 111 is ideally formed over the entire circumference (at an angle of 360 °) as shown in FIG.
From both terminals 111a and 111b of the pattern 111,
An FG signal having no disturbance in amplitude is extracted (for example, see Japanese Utility Model Application Laid-Open No. 61-81780).

[0013]

However, in response to a demand for lowering the price of a brushless motor used in such electronic equipment, it is necessary to reduce the number of electronic parts used and to produce or obtain them at low cost. In this case, in particular, in an electronic device having a driving mechanism such as the brushless DC motor, it is necessary to achieve a low price without deteriorating the rotation accuracy, and this involves difficulties.

[Single-Sided Printed Circuit Board]
In addition, it has been proposed to reduce the cost of the printed wiring board 101 and the like, which are peripheral members of the motor, rather than improving the rotation drive mechanism system accompanied by such difficulties. A typical example is a reduction in cost due to the single-sided printed wiring board 101 that forms a wiring circuit on only one side as the printed wiring board 101. That is, conventionally, a double-sided printed wiring board having printed wiring on both sides of the board or a multilayer printed wiring board further having an inner layer of a power supply layer and a ground layer is used, an FG pattern 111 is formed on one surface, and the other is formed. Wiring patterns other than the FG pattern 111 (for example, the stator 10
In this case, a wiring 112 such as a drive circuit for energizing the third coil 106 was formed. It has been proposed to use this as a single-sided printed wiring board using a single-sided copper clad board.

(Disturbance on FG Signal Amplitude: Modulation) In order to employ a single-sided printed wiring board, wiring of a drive circuit or the like conventionally printed on the rear surface is added to one surface of the printed wiring board in addition to the FG pattern 111. It must be formed together. In this case, in order to form the wiring of the drive circuit and the like, the FG pattern 111 is not formed on the entire circumference as shown in FIG. 7, but is formed, for example, along an arc having a central angle of about 315 °, and the remaining FG Wiring such as a driving circuit is formed in a fan-shaped portion where the pattern 111 is not formed (for example, see Japanese Patent Application Laid-Open No. 3-190552). In such a case,
There is a risk that the amplitude of the FG signal generated by the FG pattern 111 may be disturbed (modulated).

(The current efficiency is poor due to functional requirements.) Further, when a brushless DC motor is used for FDD or the like, the functional requirements require that the head 112 approach the center of rotation (ie, the maximum). It is required not to contact the rotor 104 even when moving to the inner circumference. In addition, the FG magnet 110 is rotated while moving close to the FG pattern 111, so that the FG magnet
Since the FG signal SFG representing the rotation speed is generated, it is necessary to bring the FG magnet 110 sufficiently close to the FG pattern 111 of the printed wiring board 101 to obtain a sufficient FG signal SFG.

Due to such functional requirements, the shape of the winding portion (drive coil) 105 is restricted, and it cannot be said that the effective portion length of the drive coil 105 for generating the motor drive torque can be sufficiently secured. The brushless motor has low current efficiency with respect to the current flowing through the drive coil 105.

(Restrictions on Wiring Pattern) Further, on the single-sided wiring board 101, necessary ICs and other electric and electronic parts (not shown), winding portions 105, Hall elements for detecting a rotational phase (not shown). ), Etc., and also necessary printed wiring (that is, wiring of a drive circuit and the like). Thus, various wirings need to be accommodated in the limited wiring area of the printed wiring board 101. For this reason, the FG pattern 111 performs patterning (wiring routing) while bypassing these wirings, and it is difficult to uniformly arrange the FG patterns 111 over the entire circumference.

That is, a sufficient wiring area cannot be secured for the FG pattern 111, and the FG pattern 111
Of the FG signal SFG is not constant in the circumferential direction, that is, the FG signal SFG is not constant in the circumferential direction. The problem of disturbance (modulation) on the amplitude of the signal occurs.

As another problem, the winding part (flat coil) 1
As a result, the printed wiring for supplying the electric current to the wiring 05 is routed while bypassing the wiring of the mounted components and other driving circuits. As a result, the wiring layout becomes longer, and the printed wiring itself must be thinned. And a relatively large voltage drop occurs, a predetermined voltage is not applied to the winding portion (stator winding) 105, and the motor torque decreases,
There is also a problem that the efficiency is reduced.

Accordingly, an object of the present invention is to provide a brushless motor having a further increased driving torque in view of the above-mentioned problems.

Another object of the present invention is to provide a brushless motor having a high current efficiency and capable of supplying a sufficient current to a drive coil.

It is another object of the present invention to provide a brushless motor in which the modulation generated in the FG signal is reduced.

It is a further object of the present invention to provide a brushless motor which simplifies the configuration of the motor through reduction or change of parts used and contributes to a reduction in the cost of electronic equipment used.

[0025]

According to the present invention, there is provided a brushless motor comprising: a stator having a frame on which a printed wiring board having a winding portion around which a coil is mounted is mounted; A rotor having a rotating shaft attached to the rotor, a disk-shaped case fixed to the rotor, and a ring-shaped main magnet fixed to the case and provided to face the winding portion. And the generated driving torque is further increased by arranging the main magnet near the outermost periphery of the disk-shaped case. Here, preferably, further, a frequency signal generating magnet is disposed on the disc-shaped case closer to the center of rotation than the main magnet is disposed, and the printed circuit board is opposed to the frequency signal generating magnet. The frequency signal detection pattern is formed at the position where the frequency signal is detected.

Further, the brushless motor according to the present invention
A stator having a frame on which a printed wiring board on which a coil is wound is mounted, a rotating shaft rotatably mounted on the frame, and a disk fixed to the rotor And a rotor having a ring-shaped main magnet fixed to the case and opposed to the winding portion, wherein the brushless motor is used for generating a frequency signal. A frequency signal generating pattern is formed at a location on the printed wiring board opposite to the main magnet which also functions as a frequency signal generating magnet and is used as a frequency signal generating magnet. The pattern has a relatively reduced number. Here, preferably, by eliminating the frequency signal generating magnet, by making the winding portion relatively large size, by relatively long effective length contributing to the rotation drive of the winding portion,
The turning force has been increased.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

First Embodiment (Structure) FIG. 1 shows the structure of a main part of a flat type brushless DC motor according to a first embodiment. As shown, the motor includes a stator 3 disposed and fixed on a frame 2 on which a printed wiring board 1 is mounted, and a printed wiring board 1.
And a rotor 4 that is arranged close to and rotatable with respect to the frame 2. The printed wiring board 1 is preferably manufactured from a single-sided copper-clad board having good dimensional stability, for example, a silicon steel sheet as a base (base material).

The stator 3 mainly comprises a frame 2 having a through hole in the center and a printed wiring board 1, and the printed wiring board 1 has a plurality of winding portions on which a stator winding is wound. A (drive coil) 105 is mounted, for example, radially with respect to the rotation center when viewed from above. The winding portion (drive coil) 105 is preferably formed by winding a winding in an inverted triangle (so-called “diaper shape”) whose outer shape is rounded at three apexes (see FIG. 5A), and is extremely thin in the thickness direction. Preferably, a thin, flat coil is used. Frame 2
A rotation shaft (shaft) 7 is rotatably inserted into the through hole.

The rotor 4 includes a metal case 8 fixed to the rotating shaft 7, and a ring-shaped driving magnet (fixed along the outer peripheral end of the case 8 so as to face the stator 3). A main magnet 9 and an FG magnet 10 fixed on the inner peripheral side of the main magnet 9 are provided. Compared to the conventional brushless motor shown in FIG. 6, the main magnet 9 and the FG magnet 11 of this embodiment
0 indicates that the positions of the respective arrangements are reversed, so that the position of the main magnet 9 is relatively arranged on the outer periphery.
Is different.

A printed wiring portion on the printed wiring board 1 facing the changed FG magnet 10 has F
The G pattern 11 is formed so as to form an arc. Similarly, as compared with the conventional brushless motor shown in FIG. 6, the position of the FG magnet 10 of the present embodiment is relatively located on the inner periphery.

(Operation) In such a configuration, when a drive current is applied to the winding portion 5 of the stator 3, the magnetic field generated by the main magnet 9 of the rotor 4 and the current flowing through the winding portion 5 cause the rotor 4 to rotate. Is applied, and the rotor 4 is driven to rotate.

At this time, the rotational force is as follows. First,
In the case of the prior art shown in FIG. 6, the force generated by the interaction between the main magnet 109 and the winding part (drive coil) 105 is F, and the length (radius) from the rotation center to the point of application of the force is r1. Then, the generated torque τ1 becomes τ1 = F · r
It becomes 1.

On the other hand, the rotational torque τ2 of the present embodiment shown in FIG. 1 is obtained by using the same components as the main magnet and the winding part and using the same current flowing through the winding part. Although the force generated by the interaction between the coil 9 and the winding portion 5 is the same F, the distance from the rotation center to the point of application of the force is different, so that τ2 = F · r2. In this embodiment, as compared with the prior art, the arrangement of the FG magnet 10 and the main magnet 9 is exchanged, and the position of the main magnet 9 is further closer to the outer periphery, so that r2 is relatively larger than r1. As a result, τ1 <τ2, and the brushless motor of this embodiment has a relatively large rotating force.

Second Embodiment (Structure) FIG. 2 shows the structure of the main part of a flat brushless DC motor according to a second embodiment. The flat brushless motor according to the second embodiment is different from the brushless motor according to the first embodiment in that the FG magnet 10 is eliminated and the
Since the function of the G magnet 10 is also used by the main magnet 9, the FG pattern 11 is
Has been moved to a position on the printed wiring board 1 facing the wiring section 5 and the winding section 5
And the size of both or one of the main magnets 9 can be made relatively large.

(Operation) By eliminating the FG magnet 10 of FIG. 1, the main magnet 9 can be changed to a larger size magnet. Further, the size of the winding part (drive coil) 5 can be changed to a larger size in accordance with this, and the effective length of the coil 5 can be made relatively long. The effective length is a portion that contributes to motor rotation driving of the winding portion 5, and corresponds to a portion extending in the radial direction from the rotation center. For details, see FIG. 5A.

However, since the function of the FG magnet is also used by the main magnet 9, the main magnet 9
When functioning as a magnet, the main magnet 9 and F
The distance between the G patterns 10 is relatively long as compared with the embodiment of FIG. 1, so that a predetermined FG signal SFG may not be obtained.

Therefore, in the brushless motor of the prior art shown in FIG. 7 and the first embodiment shown in FIG. 1, the FG pattern 11 has 60 pulses [pp
r: pulses per revolution], the vertical line (wiring portion in the radial direction) of the comb-shaped pattern is formed. In the second embodiment, however, 20 pulses [ ppr] is generated. The FG pattern 11 shown in FIG. 3A is the FG pattern 11 of the second embodiment, and the FG pattern 11 shown in FIG.
The G pattern 110 is the FG pattern 11 according to the related art and the first embodiment.

The FG pattern 11 shown in FIG.
Is formed as one pitch (one pulse is output at one pitch), and an SF signal SFG of 20 [ppr] is generated. On the other hand, the FG pattern 110 shown in FIG. 3B is formed with a rotation angle of 6 ° as one pitch and generates an SF signal SFG of 60 [ppr].

When the distance between the FG magnet and the FG pattern is long as in the second embodiment shown in FIG. 2, if the frequency is relatively high such as 60 [ppr], the FG signal S
FG may be small or unclear. But,
When the frequency to be generated is lowered to 20 pulses [ppr], which is relatively low, even if the distance between the FG magnet and the FG pattern is made relatively long, such a problem does not occur.
It was confirmed that a signal having a clear and predetermined magnitude was obtained as the signal SFG.

FIG. 4A is a diagram showing an example of the FG pattern 11 actually created. The prior art F shown in FIG.
As compared with the G pattern 110, first, the FG pattern 10 is not formed over the entire circumference but is in an arc shape, second, that three wirings are connected in series,
The radial portions (1) to (3) of the FG pattern 11
4) FG pattern 1
Each radial portion is not necessarily on the same circumference, and therefore differs in four points: the distance from the center of rotation to the radial portion is different.

The second point is that three lines of the same shape are connected in series in order to make the FG signal SFG relatively large.

Regarding the first point, as described in the section of the prior art, for example, Japanese Patent Application Laid-Open No. 3-190552 discloses an example of an FG pattern formed in an arc shape. However, in the case of the arc-shaped FG pattern 11, the FG signal SFG generated at both terminals 11a and 1b of the FG pattern 11 due to the influence (interference) of the magnetic flux from the FG pattern 11 and the leakage magnetic flux from the main magnet 9.
A problem arises that disturbance (modulation) is generated in the amplitude of the data.

To solve this problem, one of the inventors of the present application has proposed that the formation range of the FG pattern 11 is 360 ° / M or an integer multiple thereof (where M is the number of poles of the main magnetic pole). By setting the range along the circular arc, the remaining FG
F due to a portion where pattern 11 is not formed (invalid range)
It has been proposed that the effect on the G signal SFG be the same over the entire circumference and that the amplitude of the combined signal generated by the actual main magnet and the FG magnet be substantially the same (Japanese Patent Application No. 6-153779). No., Filing date: 19
July 5, 1994). For details, please refer to the application publication after the application is published.

However, according to the technique of Japanese Patent Application No. 6-153779, the FG pattern 11 which is the third problem.
The problem that the wiring lengths of the radial portions (1) to (32) are different from each other has not been solved.

In the second embodiment, the main magnet 9 has the function of an FG magnet. The main magnet 9 has eight poles, and has an angle of 45 ° per magnetic pole. Accordingly, each of the radial portions (1) to (32) of the FG pattern 11 shown in FIG. 4A is at a certain moment measured at the central angle and located at an angle of 45 ° to each other. ),
(11), (16),... Induce the SF signal SFG, and at the next moment, each radial portion (2), (7), (1) located at an angle of 45 ° with respect to each other.
2), (17),... Induce the SF signal SFG, and at the next moment, the respective radial portions (3), (8), (1) located at an angle of 45 ° with respect to each other.
3), (18),... Induce the SF signal SFG, and at the next moment, the respective radial portions (4), (9), (1) located at an angle of 45 ° with respect to each other.
4), (19),... Induce the SF signal SFG, and thereafter repeat this.

Therefore, the condition for constantly stabilizing the magnitude of the output of the SF signal SFG is as follows, assuming that the length of each radial portion of the FG pattern 11 is L (i). Σ (L (1) + L (6) + L (11) + L (16) + ...) = Σ (L (2) + L (7) + L (12) + L (17) + ...) = Σ (L (3) + L (8) + L (13) + L (18) + ...) =） (L (4) + L (9) + L (14) + L (19) + ...) (1)

That is, the SG pattern 11 shown in FIG.
At the same time, the design may be made by making the total wiring length of the portion inducing the SF signal SFG the same. Thereby, the third problem is solved.

Further, the fourth problem, FG pattern 1
1 are not necessarily on the same circumference, so that the distance from the center of rotation to each radial portion may be different. This is a problem that occurs because the wiring of various drive circuits is accommodated on a single wiring surface of the printed wiring board 1 and various electronic components are mounted thereon, as described in the section of the problem to be solved. is there. Each radial portion of the FG pattern 11
Since the distance from the rotation center to the radial portion is different, each radial portion of the FG pattern 11
Strictly speaking, even with the same wiring length L (i), the magnitudes of the generated voltages are not the same due to the different speeds of the FG magnets (which are also used by the main magnet 9) that move relatively. Therefore, it is necessary to correct the cause of the difference in the radial distance from the rotation center to each radial portion of the FG pattern 11.

[0050] The FG pattern 11 shown in FIG. 4A and B, the above equation with respect to i-th radial portion of the FG pattern 11, using _{L (i) = (r i} + L -r i). Further, in order to correct the difference in the radial distance, an integral value ∫xdx for the radial distance x = i to (i + L) is used for each radial portion of the FG pattern 11 as an example. The integral value of the radial distance x of each radial portion of the FG pattern 11 from x = i to (i + L) is as follows. ∫Xdx = _{[(r i + L) 2- (} r i) 2 ] / 2 ......... (2)

The FG pattern 11 of FIG. 4A is preferably designed by correcting the difference in the radial distance from the center of rotation to each radial portion.

[Improvement of Winding Section] Please refer to FIGS. 1 and 2 again. A winding part (driving coil) 5 is mounted on the printed wiring board 1. This driving coil 5
For example, it is formed of a flat coil and has an outer shape as shown in FIG. 5A. That is, it is preferable that the drive coil 5 is formed of an inverted triangle (so-called “conical shape”) having two outer shapes with both shoulders rounded, and a flat coil that is extremely thin in the thickness direction.

As shown in FIG. 5B, the printed wiring board 1
Above, a plurality of such driving coils 5 are radially arranged so as to surround the center of rotation. Each drive coil 5 needs to be provided with two terminals for passing current.

As shown in FIG. 5A, conventionally, these input / output terminals are provided at two places, S1 outside the coil and S2 inside the coil. In this case, as shown in FIG. 5B,
When a plurality of drive coils 5 radially arranged on the printed wiring board 1 are connected to each other in series by printed wiring, that is, the terminal S1 of one drive coil 5 is connected to the terminal S2 of another drive coil 5 In such a case, the printed wiring frequently crosses the area where the winding portion 5 is mounted, and the printed wiring is very crowded.

In this embodiment, the outer terminals are arranged at two positions, T1 and T2, at positions 180 ° apart from each other with respect to the winding 5, and the inner terminal T3 is combined into a total of three positions. T1 is used to connect the coils, and T2 is used to connect the coils or to other circuits. As a result, the congestion of the printed wiring was greatly improved, and the wiring could be simplified. The terminals T1 to T3 are formed by peeling off the coating film of the coil and allowing the coil winding to be soldered.

As shown in FIG. 5A, as the drive coil 5 employs an inverted triangle (so-called "conical shape") having two outer shapes and both shoulders rounded, as shown in FIG. 5B. When arranged radially, it is possible to mount a component such as a Hall element for detecting a rotational phase in a space formed by the rounded shoulders of the adjacent drive coils.

FIG. 6A shows the relationship between the wiring pattern of the printed wiring board 1 according to the present embodiment and the mounting positions (indicated by broken lines in the figure) of the six flat coils. As shown in FIG. 5A, in this embodiment, three locations T1 (outer circumference), T2 (outer circumference), and T3 (inner circumference) are provided as flat coil terminal locations. FIG. 6B is a diagram showing a corresponding wiring pattern according to an initial study example. In this case, only two flat coil terminals S1 (inner circumference) and S2 (outer circumference) are provided. Comparing the present embodiment (FIG. 6A) with the initial study example (FIG. 6B), in the present embodiment, two terminal locations are defined on the outer peripheral portion, and any one is set together with T3 on the inner peripheral portion due to wiring reasons. It can be seen that the use of the wiring makes it possible to realize a very simple wiring compared to the printed wiring of the initially studied example.

[Effects of the Embodiment] By using the above-described brushless motor, it is possible to provide a brushless motor having a larger driving torque simply by changing the arrangement of the mounted components. By using such a brushless motor, an electronic device such as a thin floppy disk drive having a large torque can be realized.

By relatively increasing the effective length of the winding portion contributing to the rotational drive, a brushless motor with high current efficiency can be realized.

The parts cost can be reduced by simplifying the shape of the FG magnet (first embodiment). Further, the cost of parts can be reduced by eliminating the FG magnet itself by sharing the function of the FG magnet with the main magnet.

In addition, as the number of mounted components is reduced, the area of the printed wiring board can be reduced. The reduction in the area of the printed wiring board is also an important contribution to the miniaturization of electronic devices using a brushless motor.

With the use of a single-sided printed wiring board, the length of each radial portion of the FG pattern can be corrected to suppress the occurrence of modulation. Further, the difference in the distance from the rotation center to each radial portion of the FG pattern is corrected, so that the occurrence of modulation can be more strictly suppressed.

By providing a plurality of drive coil terminals,
The printed wiring can be simplified. In this case, the wiring to the drive coil can be made short and thick, so that a voltage drop due to wiring resistance can be avoided as much as possible, and a decrease in motor torque and efficiency can be avoided.

Further, since the printed wiring for supplying current to the drive coil can be shortened, the wiring area for the FG pattern can be relatively enlarged, and the FG output can be increased. A signal can be obtained. Because of this, the speed control servo can function sufficiently and an electronic device without rotation unevenness can be realized.

The simplification of the printed wiring makes it possible to reduce or abolish the wire material that has been conventionally soldered as a so-called jumper wire because it cannot be accommodated in the printed wiring, and this can contribute to further cost reduction.

[0066]

According to the present invention, a brushless motor having a further increased driving torque can be provided.

Further, according to the present invention, it is possible to provide a brushless motor in which the modulation generated in the FG signal is reduced.

Further, according to the present invention, it is possible to provide a brushless motor having a high current efficiency and capable of supplying a sufficient current to the drive coil.

Further, according to the present invention, it is possible to provide a brushless motor which simplifies the configuration of the motor through reduction or change of the used parts and contributes to a reduction in the cost of the electronic equipment used.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main part of a brushless motor according to a first embodiment.

FIG. 2 is a diagram illustrating a main part of a brushless motor according to a second embodiment.

FIG. 3 is a diagram illustrating an FG pattern according to the present embodiment.
Here, FIG. 3A shows the FG pattern of the second embodiment,
FIG. 3B shows a conventional FG pattern for comparison.

FIG. 4 is an enlarged view of the FG pattern of FIG. 3A and a part thereof.

FIG. 5 is a diagram illustrating a stator used in the brushless motor according to the embodiment.

FIG. 6A is a diagram showing a main part of a printed wiring pattern according to the present embodiment, and FIG. 6B is a diagram showing a main part of a printed wiring pattern of an initially studied example.

FIG. 7 is a diagram showing a main part of a brushless motor according to the related art.

FIG. 8 is a diagram showing an FG pattern according to the related art.

[Explanation of symbols]

1,101 printed wiring board, 2,102 frame,
3,103 Stator, 4,104 Rotor, 5,105
Winding part (drive coil), 7,107 rotating shaft (shaft), 8,108 metal case, 9,109 main magnet (drive magnet), 10,110 FG magnet (,
Speed detection magnet, frequency signal generation magnet), 1
1,111 FG pattern (frequency signal generation pattern), 11a, 11b, 111a, 111b terminals, 1
2 heads

Claims (10)

[Claims] 1. A stator having a frame to which a printed wiring board on which a coil wound by a coil is mounted is mounted, a rotating shaft rotatably mounted on the frame, and A brushless motor including a fixed disk-shaped case and a rotor fixed to the case and having a ring-shaped main magnet provided to face the winding portion; A brushless motor characterized in that the generated driving torque is further increased by disposing it near the outermost periphery of a disk-shaped case. 2. The brushless motor according to claim 1, further comprising: a frequency signal generating magnet disposed on the disc-shaped case closer to a rotation center than a position where the main magnet is disposed; A brushless motor having a frequency signal detecting pattern formed at a position facing the frequency signal generating magnet. 3. A stator having a frame on which a printed wiring board on which a winding part around which a coil is wound is mounted is mounted, a rotating shaft rotatably mounted on the frame, and A brushless motor including a fixed disk-shaped case, and a rotor fixed to the case and having a ring-shaped main magnet provided to face the winding portion, wherein the main magnet has a frequency A frequency signal generating pattern is formed at a position on the printed circuit board opposite to the main magnet which functions as a frequency signal generating magnet, and the frequency signal generating pattern is used for each rotation. A brushless motor characterized in that the number of generated pulses is relatively reduced. 4. The brushless motor according to claim 3, wherein the magnet for generating a frequency signal is eliminated, so that the winding portion has a relatively large size, and the effective length contributing to rotational driving of the winding portion is reduced. A brushless motor that has increased rotational force by making it relatively long. 5. The brushless motor according to claim 3, wherein each of the radial portions of the frequency signal generating pattern is obtained by adding a total length of the radial portions that simultaneously generate a signal to a radial portion that generates a signal at the next instant. A brushless motor characterized by being designed to have the same length as the total length of the brushless motor. 6. The brushless motor according to claim 3, wherein each radial portion of the frequency signal generating pattern is designed by correcting for a difference in length from a center of rotation. . 7. The brushless motor according to claim 6, wherein the correction of the difference in length between the center of rotation of each radial portion of the frequency signal generating pattern and the center of rotation of the frequency signal generating pattern is performed from the center of rotation to both ends of each radial portion. Radial distance x of
= Brushless motor using integral value ∫xdx from i to (i + L). 8. The brushless motor according to claim 3, wherein, as the winding portion, an outer shape is an inverted triangle with both shoulders rounded, and a flat coil that is thin in a thickness direction is used. 9. The brushless motor according to claim 8, wherein when the plurality of winding portions are mounted on the printed wiring board radially with respect to a center of rotation, rounded shoulders of adjacent winding portions. A brushless motor equipped with a hall element and the like for detecting a rotation frequency in a region formed by the motor. 10. The brushless motor according to claim 8, wherein three or more terminals are provided for each winding portion as connection terminals with respect to the winding portion having the inverted triangle, thereby reducing a required printed wiring length. Shortened and simplified brushless motor.