JP2857531B2 - Spindle motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor, and more particularly to a thin spindle motor used for a disk drive or the like.

[0002]

2. Description of the Related Art In recent years, small floppy disk drives have been widely used in personal computers and word processors. A magnetic disk (floppy disk), which is an information storage medium of such a floppy disk drive, is formed by coating a magnetic storage film on a plastic substrate. The information stored on the surface is read by the head, or desired information is written from the outside by the head.

The magnetic storage area on such a disk surface is usually formatted in a predetermined format, whereby the storage area is divided into a predetermined format for each track or within each track, and is assigned an identification number. Therefore, the information writing / reading operation is performed immediately.

There is a strong demand for this type of spindle motor to be particularly thin and small, and various types of thin spindle motors have been proposed.

FIG. 5 is an exploded perspective view of a conventional spindle motor of this type, and FIGS. 6A and 6B are a plan view and a longitudinal sectional view of the spindle motor. In these figures, 11
Is a bowl-shaped rotor yoke through which a spindle motor shaft 18 is fixedly secured, 12 is a ring-shaped motor driving magnet fixed in the rotor yoke 11, and 13 is an outer peripheral side of the motor driving magnet 12 in the rotor yoke 11. The FG magnet 13 is divided and magnetized by a fixed FG (frequency power generation) magnet. These constitute a rotating part (rotor part) of the motor. Reference numeral 14 denotes a printed circuit board which is made of a flexible film and is disposed to face the motor driving magnet 12. On the printed circuit board 14, a plurality of drive coils 15 fixed in the circumferential direction and printed in a comb-like shape. Circuit components such as an FG (power generation) coil 16 and a plurality of sensors (not shown) for switching a coil phase are provided, and a lead wire 17 for external derivation is provided. Reference numeral 20 denotes a back yoke, which is a rear plate of the motor.
Are adhered, and the spindle motor shaft 18 is rotatably penetrated therethrough to form a fixed portion (stator portion) of the motor.

In the motor configured as described above, when a current is supplied to the drive coil 15 on the printed circuit board 14, a torque is generated and the motor drive magnet 12, ie, the rotor yoke 11, is rotated. It is transmitted to a magnetic disk via a spindle motor shaft (not shown). Further, a change in the magnetic field due to the rotation of the motor driving magnet 12 is detected by a coil phase switching sensor (not shown) on the printed circuit board 14, and the current of each phase supplied to the driving coil 15 is controlled. The rotation of the rotating part of the motor is continued. Further, the FG coil 16 also generates a pulse signal due to a change in a magnetic field associated with the rotation of the FG magnet 13 disposed on the outer peripheral side of the motor driving magnet 12, and the rotating portion of the motor is fixed based on the pulse. Speed controlled.

[0007]

As described above, as a general type of a frequency generator (FG) used for controlling the speed of a spindle motor of this type, a power generation pattern printed in a comb-like shape on a printed circuit board is used. And an FG magnet having a pair of magnetic poles. In general motors, a power generation pattern is often provided on the outer peripheral portion of the spindle motor as shown in FIGS.
However, considering the efficiency of the spindle motor, FIG.
If the FG coil 21 is installed inside the motor driving magnet 12 as in (a) and (b), good characteristics of torque and power consumption can be obtained with the same motor outer diameter.
However, in this case, since a detection (pulse) signal of the FG is taken out below the motor driving magnet 12, an accurate signal cannot be obtained due to the influence of the magnetic flux of the motor driving magnet 12 stronger than the FG magnet 22. It was difficult to arrange the FG coil inside the motor driving magnet. That is, the FG coil 21
7 is crossed by the motor driving magnet 12 and is affected by its magnetic flux. In the case of the drawing as shown in FIG. 8, an unnecessary signal as shown in FIG. 8 is generated, and the FG detection signal undulates as shown in FIG. 9 and adversely affects rotation control such as uneven rotation. Was something.

The present invention has been made in view of the above-mentioned problems of the prior art, and has been made to solve the problem. The object of the present invention is to reduce noise generated by a motor driving magnet even if an FG coil is installed inside the motor driving magnet. An object of the present invention is to provide a spindle motor capable of performing equal rotation control without being affected by rotation unevenness.

[0009]

In order to achieve the above object, the present invention provides a rotor, a motor driving magnet provided on the rotor, and a driving coil for applying a rotating force to the driving macnet. A spindle motor having a stator to which the drive coil is mounted, a power generation pattern disposed on the stator, and a frequency power generation magnet mounted on the rotor so as to face the power generation pattern. A pattern portion of the pattern is disposed within the inner periphery of the drive coil, and one of the two lead lines of the pattern is branched into at least two portions within a range affected by the magnetic force of the motor driving magnet. The wiring is arranged along both sides of the other lead wire.

[0010]

According to the above-mentioned means, one of the leader lines is branched and wired along both sides of the other of the leader lines, so that one of the leader lines is equal to a virtual leader line in the middle. Therefore, the influence of the magnetic flux received from the motor driving magnet on one and the other lead wire is the same,
Unnecessary current (noise) because there is no phase difference in power generation between both leads
Does not occur.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are views for explaining one embodiment of the present invention. FIGS. 1A and 1B are a plan view and a longitudinal sectional view schematically showing a spindle motor, and FIG. FIG. In these figures, 11 is a bowl-shaped rotor yoke through which a spindle motor shaft 18 is fixedly secured, 12 is a ring-shaped motor driving magnet fixed in the rotor yoke 11, and 13 is a side of the rotor yoke 11. With the protruding FG magnet,
These constitute a rotating part (rotor part) of the motor.
Reference numeral 14 denotes a printed circuit board which is made of a flexible film and is disposed to face the motor driving magnet 12. On the printed circuit board 14, a plurality of drive coils 15 fixed in the circumferential direction and printed in a comb-like shape. Circuit components such as an FG coil (power generation pattern) 21 and a plurality of sensors (not shown) for switching a coil phase are provided, and lead wires 40 and 41 for external derivation are provided.

Next, the leads of the FG coil 21 will be described. Base 2 inside magnet 12 for motor drive
A printed circuit board 24 is provided on 3, and the FG coil 21 is formed on the printed circuit board 24. Two lead wires 40 and 41 are led from the FG coil 21 in the outer peripheral direction. The lead wires 40 and 41 are routed in a range affected by the magnetic flux of the motor driving magnet 12. At least in the range of the lead lines 40 and 41, one of the lead lines 41 is branched into two to be the first lead line.
And the second lead line 41b. The first and second lead lines 41a and 41b are wired on both sides of the other lead line 40 at equal intervals. The first and second lead lines 41a and 41b intersect so as to straddle the other lead line 40, and this intersection (jumper)
The parts are arranged inside and outside the motor driving magnet 12, respectively. Also, the first and second lead wires 41a, which are routed outside the motor driving magnet 12,
41b is combined into one lead wire 41. 3 and 4 show the overall configuration of a spindle motor to which one embodiment of the present invention is applied. FIG. 3 is a plan view showing the overall configuration of the spindle motor, and FIG. 4 is a longitudinal sectional view of FIG. 23a is a step portion of the base 23, and 24 is a base 2
3 is a chassis to which 3 is attached.

In the above-described embodiment, the rotor 11, the motor driving magnet 12 provided on the rotor 11, and the motor driving magnet 12
, A driving coil 15 for applying a rotational force to the stator, a stator to which the driving coil 15 is attached, a power generation pattern (FG coil) 21 disposed on the stator, In the spindle motor having the frequency generating magnet 13 attached thereto, the power generating pattern 21 is disposed within the inner periphery of the drive coil 15, and the power generating pattern 21 is controlled within the range affected by the magnetic force of the motor driving magnet 12. 21 two leader lines 4
Since one of the lines 0 and 41 is branched into at least two lines and wired along both sides of the other line 40, the average position of the branched lines 41a and 41b overlaps with the line 40 and is equivalent to L = 0. Becomes Therefore, even in this case, similarly to the conventional example, the lead wires 40 and 41 from the FG coil 21 are provided.
Since a and 41b cross the motor driving magnet 12 and are affected by the magnetic flux, unnecessary signals (noise) to be generated are generated by the two lead lines 40 and 41 (41) as described above.
Since there is no phase difference between a and 41b), the unnecessary signal is canceled and does not occur. That is, both lead lines 40 and 41 (41
The noises generated in steps (a) and (41b) are equal. If the noises are observed in a differential manner, the noises are canceled, and rotation control without rotation unevenness can be performed.

[0014]

As described above, according to the present invention,
Even if the FG is installed inside the motor drive magnet, it is not affected by the noise from the motor drive magnet,
A spindle motor capable of performing rotation control without rotation unevenness or the like can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a main part showing one embodiment of the present invention.

FIG. 3 is a plan view showing an overall configuration of a spindle motor to which an embodiment of the present invention is applied.

FIG. 4 is a longitudinal sectional view of FIG.

FIG. 5 is an exploded perspective view of a conventional spindle motor.

FIG. 6 is an explanatory diagram of a conventional spindle motor.

FIG. 7 is an explanatory diagram of another conventional spindle motor.

8 is a diagram showing a generated current of a lead wire in the spindle motor of FIG.

FIG. 9 is a diagram showing an influence of an unnecessary current in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotor 12 Motor drive magnet 13 Frequency power generation (FG) magnet 15 Drive coil 21 Power generation pattern (FG coil) 40, 41 Leader 41a First lead 41b Second lead

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 21/00 H02K 3/50 H02K 11/02 H02K 29/00

Claims (1)

(57) [Claims] 1. A rotor, a motor driving magnet provided on the rotor, a driving coil for applying a rotational force to the driving macnet, a stator having the driving coil mounted thereon, and a stator disposed on the stator. In a spindle motor having a power generation pattern and a frequency power generation magnet attached to the rotor so as to face the power generation pattern, a pattern portion of the power generation pattern is disposed within an inner periphery of the drive coil. One of the two lead lines of the pattern is branched into at least two and wired along both sides of the other lead line within a range affected by the magnetic force of the motor driving magnet. Spindle motor.