JPS63209455A - Motor - Google Patents

Abstract

PURPOSE:To increase output without forming a motor to be of an enlarged type, by composing a device so that an attracting force due to permanent magnets may mainly work between the permanent magnets rotating together with rotors confronted with the permanent magnets. CONSTITUTION:The rotor 33 of a spindle motor 13 is provided with a coaxial- disc-formed upper rotor 35 and a lower rotor 36 confronted with each other at a specified distance between them, and respectively on the surfaces of the upper rotor 35 and the lower rotor 36 confronted with each other, permanent magnets 37, 38 are firmly fitted so that different magnetic poles may be confronted with each other. A coil 41 on the stator side is fitted on a coil substrate 40, and is set almost between the permanent magnets 37, 38. By torque generated by the current of the coil 41 and a magnetic field due to the permanent magnets 37, 38, the rotor 33 is rotated. An attracting force due to the permanent magnets 37, 38 of the rotor 33 works mainly between the permanent magnets 37, 38 rotating together with the rotor 33 confronted with the permanent magnets, and the attracting force between the permanent magnets 37, 38 of the rotor 33 and the stator side hardly works.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a motor that can increase output without increasing the size and is suitable for rotating disks in optical information recording/reproducing devices. .

[Problems tried to be solved by traditional slicing techniques and inventions] In recent years,
Optical information recording that can record information at high density on a recording medium (disk) by irradiating a light beam, and reproduce information recorded at high density on a recording medium at n speed.
Playback devices are attracting attention.

By the way, in order to increase the recording density of the recording medium, from angular velocity - room charge tII (CΔV), the linear velocity is constant! , 1l
It is conceivable to set it to til(CLV). However,
When using this CLV control, when moving from the innermost circumference to the outermost circumference at the time of peak acceleration, depending on the disk, the rotational speed must be nearly doubled in a very short period of time. Therefore, it is necessary to avoid increasing the output torque of the spindle motor that rotates the disk.

The optical information recording/reproducing device is miniaturized.

It is desired that the spindle motor be made thinner, and a flat brushless motor as shown in FIG. 5, for example, is used as the spindle motor.

This spindle motor 1 has a chassis 2 which also serves as a
A thrust bearing 3 is provided on the top, and a cylindrical bearing 4 is provided upright coaxially with the thrust bearing 3. On the chassis 2, a stator winding (coil) 5 is provided surrounding the bearing 4.
are arranged in a circular pattern. On the other hand, the thrust bearing 3
and a rotating shaft 6 supported by a cylindrical bearing 4,
A disk-shaped rotor 7 is attached, and a permanent magnet 8 is fixed on the surface of the yoke 7 that faces the coil 5 so as to face the coil 5 with a predetermined distance therebetween. . The rotor 7 and the rotating shaft 6 are rotated by the torque generated by the magnetic field of the permanent magnet 8 and the current of the coil 5.

In such a conventional spindle motor 1, in order to increase the output torque, the current of the coil 5 may be increased, the effective length of the coil may be lengthened, or the gap magnetic flux density may be increased.

In general, increasing the coil current increases the power consumption of the device, causing heat generation in the drive unit and increasing costs, and increasing the effective length of the coil increases the impedance and motor shape. It is not preferable to increase the size of 114<, but it is most effective to strengthen the permanent magnet 8 fixed to the rotor 7 and increase the gap magnetic flux density.

However, as the permanent magnet 8 of the conventional motor 1 is strengthened, the attractive force between the permanent magnet 8 and the chassis (yoke) 2 increases. Therefore, the rotating shaft 6 and the thrust bearing 3
There is a problem in that the friction with the motor increases, the loss increases, and the output torque does not increase much. In addition, with ball bearings, there are problems with shaft loss and zero life of the bearing due to the strong thrust load, and a thrust ball bearing dedicated to receiving thrust loads must be used.

This increases the cost of the shaft, and also increases the size of the bearing structure, making it unsuitable for thin designs.

OBJECT OF THE INVENTION] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a motor that can increase the output without increasing the size.

[Means and effects for solving the problems] The motor according to the present invention has a permanent magnet in the rotor, and utilizes the torque generated by the magnetic field of the rotor's permanent magnet and the current in the stator winding. In the device for rotating the rotor, the rotor is provided with two coaxial disc-shaped rotating parts facing each other with a predetermined interval, and different magnetic poles are opposed to each other on opposing surfaces of the two rotating parts. Permanent magnets are provided so that the stator windings are arranged between the opposing permanent magnets at a predetermined distance from both permanent magnets.

According to the present invention, the attractive force by the permanent magnets of the rotor mainly acts between the permanent magnets that face each other and rotate together with the rotor,
The attractive force between the rotor's permanent magnets and the stator side becomes weak,
It becomes possible to strengthen the permanent magnet and increase its output.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 relate to one embodiment of the present invention, in which FIG. 1 is a sectional view of a spindle motor, and FIG. 2(a) shows a disk drive unit and optical pickup of an optical information recording/reproducing device. The plan view, Fig. 2(b) shows the f! of the permanent magnet of the spindle motor. An explanatory diagram showing the arrangement of the i-pole, Figure 3 is similar to Figure 2 (
FIG. 4 is an explanatory diagram showing the actuator of the objective lens.

This embodiment is an example in which the present invention is applied to a spindle motor of an optical information recording/reproducing device.

As shown in FIG. 2(a), in the optical information recording/reproducing device 10, a disc-shaped recording medium (hereinafter referred to as
It is written as a disk. ) 12 is provided.

Further, the optical information recording/reproducing apparatus 1o is provided with an optical pickup 15. ``This optical pickup 15 consists of a fixed part 16 and a moving part 17, and the fixed part 16 is fixed on the chassis 2. On the other hand, the moving section 17 has an objective lens 18 that faces the disk 12 and is disposed so as to be movable in the radial direction of the disk 12. The fixed part 16 houses an optical system including a laser diode (not shown), and the light beam of the laser diode passes through a prism (not shown) in the movable part 17 and is directed to the objective lens 1.
The light is focused at 8 and irradiated onto the disk 12.

The moving section 17 of the optical pickup 15 is supported by an actuator 21 so as to be movable in the optical axis direction of the objective lens 18. Further, this actuator 21 is moved in the radial direction of the disk 12 by a linear motor 22. This linear motor 22
The output plate 23 has an extending portion 23a extending from the side in the moving direction, and the actuator 2 is mounted on the extending portion 23a.
1 is taken and 1 is taken.

The spindle motor 13 of this embodiment is constructed as shown in FIG. That is, a thrust bearing 31 is provided on the chassis 11, and a cylindrical bearing 32 stands up coaxially with the thrust bearing 31. The rotor 33 of the spindle motor 13 is attached to a rotating shaft 34,
This rotating shaft 34 is supported by the thrust bearing 31 and a cylindrical bearing 32. The rotor 33 has a coaxial disc-shaped upper rotor 35 and a lower rotor 36 facing each other at a predetermined interval.

The center portion of the 10-taper 35 is fixed to the rotating shaft 34 . The lower eyelet 36 has the bearing 32 in the center.
The bearing 3 is provided on the L side of the circular hole.
A cylindrical portion 36a into which the cylindrical portion 2 is loosely inserted is provided upright. and,
This cylindrical portion 36a separates the upper rotor 35 and lower rotor 36 at a predetermined interval. Permanent magnets 37 and 38 are fixed to the opposing surfaces of the ten rotor 35 and the lower rotor 36, respectively, which are magnetized to have the same number of poles so that the magnetic poles of 4T opposite each other. The permanent magnets 37 and 38 are, for example, six-pole magnetized, as shown in FIG. 2(b). The upper rotor 35 and the lower rotor 36 are attracted and fixed between the permanent magnets 37 and 38 by an attractive force. Alternatively, screws and adhesive may be used together.

Furthermore, the upper end surface of the cylindrical portion 36a of the lower rotor 36,
An engaging portion such as a serration (not shown) is provided on the surface of the upper rotor 35 that comes into contact with this upper end surface, and this engaging portion positions the upper rotor 35 and the lower rotor 36 and prevents them from shifting. It looks like this.

On the other hand, on the stator side, a second
As shown in the figure, a stator winding (hereinafter referred to as a coil) 41, which is wound into four parts, for example, is arranged in a circumferential manner. The coil board 40 is fitted with screws 4 so that the coil 41 is located approximately in the middle of the permanent magnets 37 and 38.
2 or the like to the chassis 11. Furthermore, a predetermined gap is formed between the coil substrate 40 and coil 41 and the permanent magnets 37 and 38.

Two of the coils 41 are arranged in opposite positions with the rotating shaft 34 in between and are connected in series, and two-phase currents having a phase shift of 90 degrees are supplied to the two sets of series-connected windings. It is supposed to be done.

The current of this coil 41 and the permanent magnet 37.
The rotor 33 rotates by -16 due to the torque generated by the vertical magnetic field generated by the rotor 38.

The spindle motor 13 is assembled as follows. First, the cylindrical portion 36a of the lower part 36 is loosely fitted into the bearing 32, and then the coil board 40 is fixed to the chassis 12 with screws 42 or the like. And upper rotor 3
, 5 are fixed to the rotating shaft 34, and the rotating shaft 34 is inserted into the bearing 32. Then, the permanent magnet 37 fixed on the upper O-Y 35
And the permanent magnet fixed to the lower rotor 36? The upper rotor 35 and the lower rotor 36 are attracted and fixed by the suction force with the i38.

The coil board 40 also has a phase of 90 degrees for each coil.
Hall elements 43, 43 are provided for detecting magnetic flux density in order to flow a current with a trace shift.

Further, the lower rotor 36a has a multi-+b magnetized FG (f
Abbreviation for "requency Qenerate", which indicates rotation number detection. ) Magnets 1 to 45 are fixed, and a G board 46 is fixed to the chassis 11 with a predetermined gap therebetween, forming an FG sensor for detecting the rotor rotation speed.

By the way, the linear motor 22 is constructed as shown in FIG. 3. That is, a box-shaped yoke 51 is fixed on the chassis 11, and plate-shaped permanent magnets 52 and 53 are fixed on the upper and lower inner end surfaces of the yoke 51 so that different magnetic poles face each other. There is. The permanent magnets 52 and 53 are divided into front and rear sections in the direction of movement of the output plate 23, and the 11 poles are reversed in the direction of movement. An output board 23 is arranged in the permanent magnet 52.53 questions,
On this output plate 23, as shown in FIG. 2(a), a coil 55 is mounted which is wound in a planar shape into a substantially rectangular shape. The current of the coil 55 and the permanent magnet 5
The output plate 23 to which the coil 55 is attached is moved by the force generated by the magnetic field of 2.53. In the coil 55, the portions that generate force in the moving direction are the front and rear sides in the moving direction. The direction of the current is reversed in each side portion, but since the magnetic poles of the permanent magnets 52 and 53 are also reversed before and after the moving direction, thrust in the same direction is applied to both side portions of the coil 55. occurs. In this way, in this embodiment, the linear motor 22 is formed thin, making it possible to reduce the thickness of the device.

Both ends of the output plate 23 in the direction intersecting the moving direction are
It is movably supported by guide rails 56 and 57. Front) As shown in E, the extending portion 23a of the output plate 23
An actuator 21 holding an objective lens 18 is shown above.
is installed.

Further, on the outside of the portion of the extending portion 23a supported by the guide rail 57, a scale 60 is placed between the sides.
A position sensor 61 is provided.

The scale 60 has, for example, band-shaped light shielding parts and band-shaped transmission windows (slits) formed alternately and periodically in the moving direction of the output plate 23, while the position sensor 61 has, for example, , is composed of a light emitting element and a light receiving element which are arranged opposite to each other with the scale 60 in between. The light emitted from the light emitting element and transmitted through the slit of the scale 60 is received by the light receiving element. Then, by counting the light pulses transmitted through the slit,
The movement ω of the actuator 21 can be detected.

In this embodiment, the output plate 23 to which the coil 55 is attached has a notch in the inner part, and
This reduces the force required for movement.

The actuator 21 is constructed as shown in FIG. FIG. 4(a) is a side view of the actuator, and FIG. 4(b) is a plan view of the actuator.

The moving unit 17 provided with the objective lens 18 is supported so as to be movable in the vertical direction F (in the optical axis direction of the objective lens 18) by two upper and lower leaf springs 71 and 71. The base end portion of the leaf spring 71.71 is fixed to the actuator 21 side via a piezoelectric element 72. Further, a focus coil 73 is wound around the objective lens 18,
Permanent magnets 75 and 75 fixed to the sides 74 and 74 are disposed at positions facing each other with the focus coil 73 in between. A focus control signal based on a focus error signal is input to the focus coil 73,
Based on this focus control signal, the objective lens 1
8 is to be moved. Furthermore, in this embodiment, the control (tracking control) of the movement of the objective lens 18 in the radial direction R of the disk 12 is performed by moving the actuator 21 with the linear motor 22 for both coarse and fine movements. More fine control is performed by moving the moving section 17 in the radial direction R of the disk 12 using the piezoelectric element 72.

In this embodiment configured as described above, the rotor 33 of the spindle motor 13 has an upper rotor 35 and a lower rotor 36 in the form of coaxial discs facing each other at a predetermined interval. Permanent magnets 37 and 38 are fixed to opposing surfaces of the rotor 36 so that different magnetic poles face each other.

Further, the coil 41 on the stator side is attached to the coil substrate 40 and is disposed approximately in the middle of the permanent 1637.38. Then, the rotor 33 is rotated by the torque generated by the current in the coil 41 and the magnetic field by the permanent magnets 37 and 38.

In such a configuration, the permanent magnet 3 of the rotor 33
The attraction force due to 7.38 is mainly generated between the permanent magnets 37 and 38 that rotate together with the rotor 33, and the
The attractive force between the permanent magnets 37 and 38 and the stator side (chassis 11) hardly acts. Therefore, the permanent magnet 37.
Even if 38 is strengthened, the thrust bearing 31 that supports the rotating shaft 34 will only be subjected to approximately 0,000 of the rotor 33, and there will be less loss due to friction between the thrust bearing 31 and the rotation @34, so the permanent magnet 37 and 38, it becomes possible to avoid increasing the output of the spindle motor 13.

In addition, since the permanent magnets 37 and 38 are arranged on both sides of the coil 41, the magnetic flux density increases compared to a case where a permanent magnet is arranged on one side of the coil, and the output of the spindle [-13] increases. Increase 1-ru.

In this way, the output can be increased by strengthening the permanent magnets 37 and 38, so by avoiding an increase in the coil current, the power consumption of the device increases, the heat generation of the drive part, and the loss are increased. In addition, by increasing the coil ear effect length, the impedance increases and the motor shape increases! It does not invite any change.

Incidentally, the present invention is based on the two-phase brush 1 nos [-
The present invention can be applied not only to motors but also to various permanent magnet rotor type motors in which a permanent magnet is provided in the rotor. Also,
The present invention can be used not only in the spindle motor of an optical information recording 111/reproducing device but also in various devices.

[Effects of the Invention] As explained above, according to the present invention, even if the permanent laminated stone is strengthened, the attraction force by the permanent magnets is mainly uniform between the permanent magnets facing each other and rotating together with the rotor. As the motor moves, the attractive force between the permanent magnets of the rotor and the stator becomes weak, and the effect is that the permanent magnets can be strengthened and the output can be increased without increasing the size of the motor.

[Brief explanation of the drawing]

1 to 4 relate to one embodiment of the present invention, in which FIG. 1 is a sectional view of a spindle motor, and FIG. 2 (a) shows a disk drive unit and optical pickup of an optical information recording/reproducing device. The plan view, Figure 2(b) is an explanatory diagram showing the arrangement of the magnetic poles of the permanent magnet of the spindle motor, and Figure 3 is Figure 2(a).
4 is an explanatory diagram showing an acticoator of an objective lens, and FIG. 5 is a sectional diagram of a conventional spindle. 13...Spindle motor 33...Rotor 34...Rotating shaft 35...
・Upper rotor 36...Lower rotor 37.38...
・Permanent magnet 40...Coil board 41...Coil Figure 1 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In a motor in which a rotor is provided with a permanent magnet and the rotor is rotated using torque generated by a magnetic field by the permanent magnet of the rotor and a current in a stator winding, the rotor is spaced apart from each other at a predetermined interval. It has two coaxial disk-shaped rotating parts that open and face each other, and on the opposing surfaces of these two rotating parts,
Permanent magnets are provided so that different magnetic poles face each other, and the stator winding is arranged between the opposing permanent magnets at a predetermined distance from both permanent magnets. motor.