JP3213645B2 - Electromagnetic drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic driving device, and more particularly to an electromagnetic driving device which can be suitably used as a driving means of an objective lens of an optical disk recording / reproducing device.

[0002]

2. Description of the Related Art An electromagnetic drive device used for an optical disk recording / reproducing device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-106155. FIG. 9 is a perspective view showing the overall configuration of the electromagnetic drive device, and FIG. 10 is a II view of the device shown in FIG.
FIG. 2 is a cross-sectional view along the line II.

FIGS. 9 and 10 show a state in which an electromagnetic driving device is used as a driving means of an optical pickup of an optical disk reproducing device. Reference numeral 101 denotes a linear motor, and this linear motor 101 is disposed on the back side of an optical disk 102 which is rotatably supported in the θ direction. The linear motor 101 has magnets 103 and 104 magnetized in the thickness direction.
, Magnetic yokes 105 and 106, coils 107 and 108, and a bobbin 109 around which the coils 107 and 108 are wound. The yokes 105 and 106 are disposed so as to face the magnets 103 and 104, respectively. These yokes 105 and 106 are formed with a pair of through holes 11 formed in a bobbin 109.
0 and 111 are inserted. The bobbin 109 may be made of a non-magnetic material at least at the outer peripheral portion, and may be formed of a metal such as aluminum at the central portion. In the bobbin 109, holes 112V and 112H are formed in an L shape between a pair of through holes 110 and 111 formed in the bobbin 109, and an optical path is changed at an intersection with the holes 112V and 112H. The reflecting mirror 113 is fixed. On the exit side of the hole 112V facing the optical disk 102, an optical pickup 116 having an objective lens 115 is mounted via a mount 114, and a reading optical system 117 is provided in a direction in which the hole 112H is extended. Reading optics
117 is a laser diode 118, a beam splitter 119
, A collimator lens 120, a light receiving optical system 121, a photodiode 122, and the like. The light emitted from the laser diode 118 is reflected by the reflecting mirror 113 via the collimator lens 120, enters the optical disk 102 via the optical pickup 116, is reflected there, and is further reflected by the optical pickup 116, the reflecting mirror 113, The optical path is changed by a beam splitter 119 via a collimator lens 120, the light is incident on a photodiode 122, and the information recorded on the optical disk 102 is read.

[0004]

An electromagnetic drive device used for moving an optical pickup means such as an objective lens in such an optical reproducing apparatus is required to have high drive sensitivity and small size. . It is also desirable that resonance does not occur during driving. That is, in the electromagnetic driving device shown in FIGS. 9 and 10, the center F of the force generated in the coils 107 and 108 when viewed from the X direction and the center of gravity G of the movable portion of the linear motor 101 match. Is desirable. The center of force F and the center of gravity G of the movable part are, for example, Z
If the movable part moves in the X direction, a moment about the Y axis is generated in the movable part, and
Resonance will be induced around the axis.

As is apparent from FIGS. 9 and 10, in such an electromagnetic drive device, the movable portion of the linear motor 101 has an optical pickup 11 above the coils 107 and 108.
5 and the load of the magnetic head, etc.
It is necessary to add a counterbalance on the opposite side of these loads in the direction, or to fill the Z (-) side of the bobbin 109.

For this reason, there is a problem that the entire movable portion of the linear motor 101 becomes heavy and the drive sensitivity of the electromagnetic drive device is reduced. Further, there is also a problem that the movable portion becomes thicker in order to attach the counterbalance, and does not meet the purpose of miniaturization. The positions of the coils 107 and 108 cannot be raised because the optical disk 102 and its cartridge (not shown) exist above.

[0007]

Means for Solving the Problems Claims for solving the above problems
The invention of an electromagnetic drive device according to Item 1 is characterized in that a movable portion having at least one coil and a linear portion passing through the coil are provided.
A first magnetic member disposed to extend in, comprising a second magnetic member which is disposed to face through the first magnetic member and the magnetic gap, in the magnetic gap at least a portion of said coil And moving the movable portion to the first magnetic field.
In the electromagnetic driving device configured to be driven linearly along the conductive member, the center of the magnetic surface of the first magnetic member is connected to the coil with respect to the center of the magnetic surface of the second magnetic member. Perpendicular to the direction of the generated force , and
The magnetic surface of the conductive member and the magnetic surface of the second magnetic member face each other.
In a direction orthogonal to the direction in which the image is drawn.

According to a second aspect of the present invention, there is provided an electromagnetic drive device comprising: a movable portion having at least one coil; and a first magnetic member disposed linearly extending through the coil. Member and the first magnetic member via a magnetic gap.
Comprising a second magnetic member disposed in countercurrent, before at least a portion of the coil by positioning in the magnetic gap
An electromagnetic drive device configured to drive the movable portion linearly along the first magnetic member , wherein a center of a magnetic surface of the second magnetic member is the magnetic surface of the coil. The direction of the force generated in the coil is perpendicular to the center of the portion located in the gap , and the magnetic force of the first magnetic member is
In a direction in which the surface and the magnetic surface of the second magnetic member face each other.
And is shifted in a direction orthogonal to the direction.

As described above, in the electromagnetic drive device of the present invention,
A movable part comprising at least one coil, said coil
Magnetic member arranged linearly extending through the inside
And opposed to the first magnetic member via a magnetic gap.
And a second magnetic member arranged in
At least a portion is located in the magnetic gap and
The moving part is driven linearly along the first magnetic member.
The electromagnetically actuating apparatus urchin configuration, the center of the magnetic surface of the first magnetic member relative to the center of the magnetic surface of the second magnetic member, and perpendicular to the direction of the force generated in the coil, or
The magnetic surface of the first magnetic member and the magnetic surface of the second magnetic member
By shifting in a direction in which the magnetic surface perpendicular to the direction opposite
Or that, alternatively, the center of the magnetic surface of the second magnetic member relative to the center of the portion located in the magnetic gap of the coil, perpendicular to the direction of the force generated in the coil, or
The magnetic surface of the first magnetic member and the magnetic surface of the second magnetic member
Shift in the direction perpendicular to the direction in which the magnetic surface faces
As a result, the drive that acts on the center of gravity of the movable part and the coil
It is possible to adjust the center of power (drive point).
Therefore, when this electromagnetic drive device is applied to an information recording / reproducing device and an optical pickup, a magnetic head, and the like are mounted on an upper portion, a counter balance mounted on a lower portion is reduced or such No counter balance is required, and the device can be reduced in size and weight. Further, the drive sensitivity can be improved.

Further, the invention of the electromagnetic drive device according to claim 3 is used for a disk recording / reproducing device.
The at least one part of the coil is located in an opening of a disk cartridge for accommodating a disk.

Thus, according to the present invention, claim 1
Or, when the electromagnetic drive device described in 2 is applied to a magneto-optical disk recording / reproducing device or the like, and information is recorded / reproduced, a part of the coil is inserted into an opening of a disk cartridge containing a magneto-optical disk or the like. The recording / reproducing apparatus can be reduced in size and thickness in addition to the function and effect of claim 1 or 2 .

[0012]

1 to 6 show the configuration of a first embodiment of the electromagnetic drive device of the present invention applied to a magneto-optical disk recording / reproducing device. FIG. 1 is a perspective view showing the overall configuration of the electromagnetic drive device, FIG. 2 is an exploded perspective view showing the configuration of a movable portion of the electromagnetic drive device, FIG. 3 is a cross-sectional view of the device shown in FIG. 5 is a perspective view showing an actuator configuration of the optical pickup mounted on the electromagnetic driving device, FIG. 5 is an exploded perspective view of the actuator, and FIG. 6 is an exploded perspective view of the actuator shown in FIG. 5 when viewed from below.

As shown in FIG. 1, in the electromagnetic drive device of the present invention, a spindle motor 2 is fixed on a deck base 1, and a magneto-optical disk 3 is rotatably supported by the spindle motor 2. . On the deck base 1, a movable portion 4 including an actuator 22, which will be described later, is movably supported in the X direction.

The detailed configuration of the movable section 4 is as shown in FIG. That is, a carriage 20 made of aluminum die-casting is provided, and an actuator 22 is disposed on the spindle motor side of the carriage 20 by three screws 21, 21, 21. Further, a mirror 45 is mounted in the annular concave portion 20a of the carriage 20 so as to be located directly below the objective lens 40. As shown in FIG. 1, a fixed optical system 5 is provided behind the carriage 20 on the side opposite to the spindle motor. A light-emitting element and a light-receiving element (not shown) are provided in the fixed optical system 5, and a light beam emitted from the light-emitting element is taken into the movable section 4, reflected by the mirror 45, and The light is incident on the magneto-optical disk 3 via the lens 40, and the light reflected by the magneto-optical disk 3 is mirrored again.
The light is reflected at 45 and guided to the light receiving element in the fixed optical system 5.

The opposite side of the spindle motor of the carriage 20 rises upward, and one end of a spring 23 is fixed to the upper side surface 20c of the rising portion 20b by two screws 24,24. A slider 26 having a field coil 25 for generating a magnetic field on the information recording surface of the magneto-optical disk 3 is fixed to the other end of the spring 23. The slider 26 is caused to float on the rotating magneto-optical disk 3 by a very small amount. Since it is necessary to sandwich the magneto-optical disk 3 between the objective lens 40 and the slider 26, the length of the spring 23 in the X direction and the upper surface of the rising portion 20b of the carriage 20
The length in the X direction between 20c and the objective lens 40 must be sufficiently long.

When information is recorded on the magneto-optical disk 3 using magnetic field modulation, it is necessary to reduce the size of the field coil 25 in order to reduce the inductance of the field coil 25. Therefore, the effective magnetic field range of the magnetic field generated by the field coil 25 is also
For example, the size is reduced to about 150 μm square. Therefore, it is necessary to reduce the displacement between the light spot of the objective lens 40 and the field coil 25.

Usually, in a magneto-optical disk drive, the temperature is
It varies from 5 ℃ to 60 ℃. Here, let us consider a case where the distance from the light spot formed by the objective lens 40 to the screw 24 for fixing the spring 23 is 30 mm, and the temperature in the magneto-optical disk device changes 55 ° C. from 5 ° C. to 60 ° C. The displacement between the light spot formed by the lens 40 and the field coil 25 is such that the linear expansion coefficient of aluminum, which is the material of the carriage 20, is 23.6 × 10 ^-6 / ° C., and the wire of the chrome nickel stainless steel, which is the material of the spring 23, If the expansion coefficient is 17.3 × 10 ⁻⁶ / ° C., it will be 10 μm. Since such a deviation is within 10% of 150 μm, which is the effective magnetic field range of the magnetic field generated by the field coil 25, it can be said that the deviation is within the allowable range.

When chrome stainless steel is used as the material of the spring 23, the linear expansion coefficient α of chrome stainless steel is 9 ×
Since it is about 10 ^-6 / ° C, the objective lens 40 and the field coil 25
Is as large as 24 μm. Therefore,
When aluminum die casting is used for the carriage 20,
Since the coefficient of linear expansion of chromium-nickel stainless steel is closer to aluminum than the coefficient of linear expansion of chromium stainless steel, a method using chromium-nickel stainless steel as the material of the spring 23 is preferable. Even when the carriage 20 and the spring 23 are made of other materials, it is preferable to combine them having a coefficient of linear expansion as close as possible (for example, a difference in coefficient of linear expansion is within 30%).

A cover 22a for covering the actuator 22 is further fixed on the carriage 20. Carriage 20
U-shaped concave portions 20d, 20d are provided on both side surfaces in the Y direction.
Are formed, and coils 27, 27 wound in a quadrangular pillar shape are fixed to the concave portions 20c, 20c, respectively. As shown in FIG. 1, center yokes 6, 6 are inserted into the coils 27, 27, and the center yokes 6, 6 are fixed to the deck base 1 by screws 7, 7, 7, 7, respectively. A substantially U-shaped side yokes 8, 8 are in contact with the center yokes 6, 6, and the side yokes 8, 8 are also fixed to the deck base 1 by screws 9, 9, respectively. Magnets 10, 10 magnetized in the thickness direction are fixed inside the side yokes 8, 8, and the magnets 10, 10 and the center yokes 6, 6 are fixed.
And a magnetic gap is formed between them. Coil 27, 27
When a current is applied to the coil 27, a force is generated in one side of the coils 27, 27 located in the portion where the magnetic gap is formed in the X direction, and the movable portion 4 moves in the X direction.

One end 28a of the FPC 28 is fixed to the lower surface of the carriage 20, the FPC 28 extends in the Y direction via a bent portion 28b, and the other end 28c is fixed on the deck base 1. I have. Since the FPC 28 is disposed so that the bent portion 28b is located between the movable portion 4 and the spindle motor 2, it does not interfere with the light beam emitted from the fixed optical system 5. The FPC 28 establishes electrical connection to the coil 27 and the actuator 22. One end of another FPC 29 is attached to the side surface 20e of the rising portion 20b of the carriage 20. An L-shaped plate 30 is fixed to the other end of the FPC 29.
Are fixed to the fixed optical system 5 as shown in FIG. This FP
AE for detecting an abnormality of the field coil 25 and the slider 26 or the slider 26 attached to the spring 23 via the C29.
An electrical connection with a sensor (not shown) is established. Since the FPC 29 is arranged above the light beam emitted from the fixed optical system 5, it does not interfere with the light beam.

An electric circuit 31 including a circuit for driving the field coil 25 and a preamplifier circuit for an AE sensor (not shown) is provided at the other end 29a of the FPC 29. Therefore, the distance between the field coil 25 and the AE sensor (not shown) and the electric circuit 31 may be short, and noise is hardly generated. Further, the mass of the entire movable part 4 is also reduced. If there is room in the drive sensitivity of the movable section 4, this electric circuit 31
Is disposed on the end portion 29b of the FPC 29 on the carriage 20 side, so that the generation of noise can be further suppressed.

At one end of the carriage 20 in the Y direction, two bearing mounting portions 20f are provided, and the outer ring is provided at each of the mounting portions 20f, 20f.
The shafts of the letter-shaped bearings 32, 32 are press-fitted. Also,
At the other end of the carriage 20 in the Y direction, a bearing mounting portion 20g for mounting a bearing in an oblique direction is provided.
The outer ring press-fits the shaft of the cylindrical bearing 33 into the mounting portion 20g. This bearing 33
Is the angle δ between the axis 33a and the XY plane as shown in FIG.
Is set to be larger than 45 ° (for example, 50 °). A preload spring 35 is mounted below the mounting portion 20g of the carriage 20 via a screw 35a. An outer ring press-fits a cylindrical bearing 36 into the tip of the preload spring 35.

As shown in FIG. 1, the center yokes 6, 6
Reference guide rails 11a and 11b are fixed to the deck base 1 by two Sarabis 12a, 12a, 12b and 12b, respectively. The guide rails 11a and 11b are movably inserted into openings 20h provided in the Y direction of the carriage 20, respectively. The guide rail 11a on the reference side is 2
Abuts the V-shaped outer ring of the two bearings 32, 32,
The outer race of the bearing 33 abuts on the driven-side guide rail 11b, and the bearing 36 abuts while applying a preload. Thus, the movable part 4 has four bearings 3
2, 32, 33, 36 and the two guide rails 11a, 11b are movably supported in the X direction.

[0024] As shown in cross section in FIG. 3, two guide rails 11a, Comparing the height in the Z direction 11b, towards the driven side of the guide rail 11b is seen to be higher by Z _1. The midpoint S of the line connecting the centers of the two guide rails 11a and 11b is the objective lens when viewed from the X direction.
It is on 40 optical axes. The reason for disposing the guide rails 11a and 11b in the Z direction is to apply a load in the thrust direction to the bearings 32 and 32 that are in contact with the guide rail 11a on the reference side, and to reduce the play of the bearings 32 and 32 themselves. To get rid of it. Since the driven side guide rail 11b is higher in the Z direction, the bearing 33 abuts against the guide rail 11b.
Is higher in the Z direction, and the upper end thereof approaches the magneto-optical disk 3. However, in this embodiment, as described above, the bearing 33 is inclined at 50 °, which is inclined at an angle of more than 45 ° with respect to the XY plane. The inclined arrangement prevents the upper end from approaching the magneto-optical disk 3.

As shown in FIG. 2, since the bearings 33 and 36 abutting on the guide rail 11b on the driven side are disposed at positions shifted in the X direction with respect to the actuator 22, these bearings are provided. The bearing can be positioned closer to the center in the Y direction. As a result, the dimension of the entire movable section 4 in the Y direction can be reduced, and the weight of the movable section 4 can be reduced. Also, like this, bearings 33, 36
As a result, the bearing 33 can be located in the opening 3b of the cartridge 3a of the magneto-optical disk 3 as shown in FIG. Interference can be prevented. Further, a reference-side guide rails 11a, Z-direction displacement of the driven-side guide rail 11b, while ensuring Z _1, will be closer to the midpoint S of the guide rails to the magneto-optical disk 3 side, the movable portion 4 Can be reduced in the Z direction.

The center in the Z direction of the magnets 10, 10 abutting on the side yokes 8, 8, is in relation to the center in the Z direction of the center yokes 6, 6, the side yokes 8, 8, and the coils 27, 27. only Z ₂ is higher. Therefore, the magnetic flux density center f of the magnetic flux acting on the coils 27 in the magnetic gap existing between the center yokes 6, 6 and the magnets 10, 10 is substantially equal to the center of the center yoke 6 in the Z direction. It will be present at a position higher by Z ₂ × 1/2. The center f of this magnetic flux density is one coil
The driving center of the X-direction driving force generated in the two coils 27, 27 is the driving center of the X-direction driving force generated in the 27
Is located on the optical axis of the objective lens 40 when viewed from the X direction, as shown in FIG. 3, and is located at the midpoint S of the guide rails 11a and 11b.
Matches. Also, the center of gravity G of the movable part 4 is
27, the driving center F coincides with 27. As described above, in the present invention, the height of the driving center F of the coils 27, 27 in the Z direction is determined by the center yoke 6, the 6 side yokes 8,
8. The height of the coils 27, 27 in the Z direction and the magnet 1
Compared to the case where the heights of 0 and 10 match, Z ₂ × 1
/ 2 closer to the magneto-optical disk 3 side.

Since the height of the drive center F is closer to the magneto-optical disk 3 than the center of the coils 27, 27 in the Z direction, the coils 27, 27 themselves can act as a balancer. Therefore, since the actuator 22, the spring 23, and the like are located closer to the magneto-optical disk 3 than the drive center F, the mass of the balancer required to make the center of gravity of the movable portion 4 coincide with the drive center F is reduced. Or eliminate the balancer. As a result, the entire movable section 4 can be reduced in weight and drive sensitivity can be enhanced, and the thickness of the movable section 4 in the Z direction can be reduced to reduce the size of the entire apparatus.

In this embodiment, the reference side guide rail is used.
As two bearings 32, 32 whose outer ring shape is V-shaped are used as bearings to be in contact with 11a,
The number of bearings can be reduced and cost can be reduced as compared with a case where four cylindrical bearings are used. Further, the bearing 36 is preloaded with respect to the driven-side guide rail 11b by combining bearings 33 and 36 having a cylindrical outer ring shape. When a bearing having a V-shaped outer ring is applied to the driven guide rail 11b and the bearing is held by a preload spring to apply a preload, the bearing is displaced by external vibration or resonance of the preload spring. As a result, the movable section 4 moves in an undesired direction. With the configuration as in the present embodiment, since the bearing 33 is fixed, the preload spring
Even if 35 resonates, it is difficult for the movable section 4 to resonate.

Actuator using FIGS. 4, 5 and 6
22 will be described. 4 is a perspective view showing the overall configuration of the actuator 22, FIG. 5 is an exploded perspective view of the actuator 22, and FIG. 6 is an exploded perspective view of FIG.

The objective lens 40 is fixed to the center of the lens holder 41. Recesses 41a, 41a are formed at both ends in the Y direction of the lens holder 41, and focus coils 42, 42 wound in a quadrangular prism shape are disposed in the recesses 41a, 41a. The recesses 41a, 41a are provided with a bottom 41b, a side 41c, and a protrusion 41d projecting upward from both ends in the X direction of the bottom 41b, respectively.
The bottom surfaces of the focus coils 42, 42 are the bottom surfaces of the concave portions 41a, 41a.
The outer surface is positioned and fixed to the side surface 41c, the inner surface by the convex portion 41d, and the outer surface to the side surface 41c. A tracking coil is provided on the outer peripheral side of the focus coil 42.
43 and 43 are fixed respectively. These tracking coils 43 are arranged so as to be shifted in opposite directions in the X direction. Note that the convex portion 41d is provided with a yoke 54 described later.
Of the lens holder 41 in the X direction.

A U-shaped balancer 44 is fixed to the bottom surface of the lens holder 41 along the outer periphery of the holder. This balancer 44 is made of a phosphor bronze plate. FIG.
As shown in FIG. 5, arc-shaped convex portions 41e and 44a are formed on one side of the lens holder 41 and one side of the balancer 44, respectively. The light beam emitted from the fixed optical system 5 (see FIG. 1) The mirror 45 (see FIG. 2) passes just below the convex portion 44a.
Reference). Since the balancer 44 is fixed substantially along the outer periphery of the bottom surface of the lens holder 41, the torsional rigidity of the lens holder 41 around the X axis is increased, and the resonance frequency is increased. Further, the convex portion 41e formed on the lens holder 41 also acts to increase the rigidity of the lens holder 41. Also,
On the bottom side of the lens holder 41, a square concave portion (41j) for installing the mirror 45 is formed.
The configuration is such that the mirror 40 and the mirror 40 are close to each other.

Projections 41f, 41f are formed at both ends of the lens holder 41 in the X direction.
Grooves 41g, 41g are formed on the upper and lower surfaces of 41f, 41f, respectively, and one end portions 46a,
46a, 47a, 47a are fixed. One ends 46a, 46a, 47a, 47a of these springs are also directly soldered to terminals (not shown) of the focus coil 42 and the tracking coil 43. The other ends 46 of the springs 46, 46, 47, 47
b, 46b, 47b, 47b are grooves 48a, 48a, 48b, 48b formed at both ends in the X direction of the upper end of the holding member 48.
Are fixed by soldering. These grooves 48a, 48a, 48 of the holding member 48 formed of plastic are used.
A pattern is formed of copper on the back side of b, 48b and the holding member 48 so as to make electrical connection to the springs 46, 46, 47, 47. Therefore, the FPC is not required here, and the problem that stress is applied to the spring due to deformation of the FPC can be prevented.

The springs 46, 46, 47 and 47 are formed by etching a beryllium copper plate and partially damped.
Covered with 9,49. The springs 46, 46, 47, 47 hold the lens holder 41 movably in the X and Z directions. These springs 46, 46, 47, 47
Are bent inward in the X direction, and the left and right springs 46
Between the lens holder 41 and the end 46a, 46a on the lens holder 41 side;
As compared with the interval between 47a, 47a, the end 46b,
46b; the space between 47b and 47b is configured to be wide. With this configuration, the dimension in the X direction on the lens holder 41 side can be reduced, and the torsional rigidity around the Y axis can be increased.

Two bosses (not shown) are formed on the bottom surface of the holding member 48. The bosses are engaged with holes 50a, 50a formed in the base 50, and the holding member 48 is connected to the base 50. Position on top. The holding member 48 is integrally formed with a housing 48d via a connecting portion 48c. Housing 48d
Is formed with a concave portion 48e, and when the actuator 22 is assembled, the flag 41h provided at one end of the projecting portion 41f of the lens holder 41 is located in the concave portion 48e.
In the housing 48d, the LED 51 and the PD 52 are fixed, and the light receiving surface of the PD 52 is divided into two in the X direction. The light emitted from the LED 51 in the Y direction is
Since the central portion is shielded from light by h and enters the PD 52, the shadow of the flag 41h is on the dividing line of the PD 52. Therefore, by obtaining the difference between the outputs of the light receiving surfaces of the PD 52, the flag 41h, that is, the position information of the objective lens 40 in the X direction or the information of the moving speed can be obtained.

The connecting portion 48c of the holding member 48 includes upper and lower springs 4
Because it is located between 6, 47, by this connecting part 48c,
The outer shape of the actuator 22 is not increased.

The springs 46, 46, 47, and 47 assemble the lens holder 41 and the holding member 48 in a state where they are positioned using a jig. Also, the flag 41h of the lens holder 41
Are integrally formed with the lens holder 41 and the housing 48d is also integrally formed with the holding member 48, so that the LED 51, the PD 52,
The mutual positional accuracy of the flags 41h is improved, and the difference output of the PD 52 is less likely to be offset. This configuration eliminates the need for position adjustment work during assembly. Further, the position sensor of the objective lens 40 (flags 41h, L
The ED 51 and the PD 52) are located on the opposite side of the fixed optical system 5 with respect to the mirror 45, so they do not interfere with the light flux between the mirror 45 and the fixed optical system 5, and the position sensor unit can be easily arranged. is there.

The base 50 is formed by pressing a single iron plate. Four yokes 53, 53, 54, 54 extending in the X direction
Are raised in the Z direction, and magnets 55 and 56 magnetized in the thickness direction are fixed to the inner side surfaces of the outer yokes 53 and 53, respectively, with the N poles inside. A magnetic gap is formed between the magnets 55, 56 and the inner yokes 54, 54. One side in the X direction of the outer yokes 53, 53 is bent inward to form a yoke 53a. As shown in FIG. 4, when the actuator 22 is assembled, one side 43a, 43a of the tracking coil 43 faces the magnets 55, 56, respectively, and the other side 43b, 43
b is a position facing the yokes 53a, 53a, respectively. Since the direction of the magnetic flux in the magnetic gap is opposite in the Y direction between one side 43a and the other side 43b of the tracking coil 43, the forces generated on these sides 43a and 43b are the same in the X direction. Turn. One side of the focus coil 42 is also located in the magnetic gap, and a force is generated in the Z direction.

An FPC 55 is attached to the lower surface of the base 50, and the LEDs 5 passing through holes 50b provided in the base 50 are provided.
1. Soldered to the terminals of the PD 52 to establish electrical connection between these elements. Also, one end of the base 50 in the X direction is
It is bent upward at a right angle to form a reinforcing portion 50c, and the other end is provided with a light beam 50 whose lower side is cut out in an arc shape.
d is formed, and the light emitted from the fixed optical system 5 is incident on the mirror 45 through immediately below the beam 50d.

FIG. 7 is a diagram showing the configuration of the second embodiment of the present invention. In the following embodiment, only portions different from those of the above-described first embodiment will be illustrated and described. The same reference numerals are used for the same components as in the first embodiment.

In the second embodiment, the side yoke 8 and the magnet 10 are located in the coil 27, and the center yoke 6
Is arranged outside the coil 27. In this embodiment, than the height of the center in the Z direction of the magnet 10 and the coil 27, the center in the Z direction of the center yoke 6 are arranged so as to be higher by Z _2. Therefore, the height of the driving center f of the driving force generated in the coil 27 can be increased by about Z ₂ × 1/2.

FIG. 8 is a diagram showing the configuration of the third embodiment of the present invention. Here, a guide rail for indicating the movable portion 4
Of the guide rails 11a on the reference side among the reference rails 11a and 11b, the outer ring press-fits a V-shaped bearing into the lower end of the carriage 20 in the Y direction, and the outer ring also presses the V-shaped bearing 60 on the driven side. It is fixed to a spring and attached to the carriage 20. Notch 61 at one corner of center yoke 61, 61
a, and guide rails are formed in the cutouts 61a, 61a.
11a and 11b are located respectively. The notch 61a of the center yoke 61 on the reference side is formed on the lower side, and the notch 61a of the center yoke 61 on the driven side is formed on the upper side.
The positions of a and 11b are made different in the Z direction. The coils 27, 27 are located around the center yokes 61, 61 and the guide rails 11a, 11b. Y of coil 27, 27
Side yokes 62, 62 are arranged on the outside in the direction, and a magnet 1 is provided inside the side yokes 62, 62.
0 and 10 are fixed. These members are coils 27, 27
And with respect to the center in the Z direction of the center yoke 61, the center in the Z direction of the magnet 10, 10 is arranged to be higher by Z _2. Also, side yoke 6
As shown in FIG. 8, the ends 2 and 62 are formed by folding the ends inward, and the magnets 10 are fixed to the rising portions 62a.

As described above, in this embodiment, the center yokes 61, 61 and the guide rails 11a, 11b are
Also, since the side yokes 62, 62 arranged in 7, 27 have a cross-sectional area other than the fixed portions of the magnets 10, 10, the thickness of the fixed portions of the side yokes 62, 62 to the magnets 10, 10 is small. For this reason, the interval between the rising portions 62a, 62a of the two side yokes 62, 62 in the Y direction can be reduced, and the portion from the side yoke 62 to the side yoke 62 of the driving device is placed in the opening 3b of the cartridge 3a. I am trying to position it. That is, a part of the drive means and a part of the support means for the bearing 60 and the guide rail 11b are located in the opening 3b of the cartridge 3a. Therefore, the magnets 10, 10 and the coils 27, 27 can be brought closer to the magneto-optical disk 3, and the counter balancer or the like can be made smaller or eliminated, and the entire device can be made thinner and thinner. It can be small.

In the above-described embodiment, an example has been described in which the electromagnetic drive device of the present invention is applied to a magneto-optical disk recording / reproducing device. However, the present invention is also applicable to an optical disk device, a magnetic disk device having a magnetic head, and the like. It goes without saying that the present invention can be applied.

[0044]

As described in detail above , according to the electromagnetic driving device of the present invention , at least one coil is provided.
A movable part and a linearly extending arrangement extending through the coil.
A first magnetic member, and the first magnetic member
And a second magnetic member disposed to face through a gap.
In addition, at least a part of the coil is
And moving the movable portion along the first magnetic member.
Electromagnetic drive device that is configured to drive linearly
And the second magnetic member has the second magnetic member with respect to the center of the magnetic surface.
The center of the magnetic surface of the magnetic member is generated in the coil.
Perpendicular to the direction of the force and with the magnetic surface of the first magnetic member
In the direction in which the magnetic surface of the second magnetic member faces
Shift in the orthogonal direction (Z direction), or
The center of the portion of the coil located in the magnetic gap
The center of the magnetic surface of the second magnetic member in the Z direction
Drive that acts on the center of gravity of the movable part and the coil
The center of the force (drive point) can be adjusted.
The counter balance attached to the movable part
Or, such a counter balance is unnecessary.
Therefore, the size and weight of the device can be reduced, and an electromagnetic drive device with high drive sensitivity can be provided. In addition, either
For disk recording / reproducing device to which such electromagnetic drive device is applied
At least part of the coil houses the disk
In the opening of the disc cartridge
With this configuration, in addition to the above-described functions and effects, the overall size of the recording / reproducing apparatus can be reduced in size and thickness.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a first embodiment of an electromagnetic drive device according to the present invention.

FIG. 2 is an exploded perspective view of a movable portion of the device shown in FIG.

FIG. 3 is a sectional view in the Y direction of the device shown in FIG. 1;

FIG. 4 is a diagram showing a configuration of an actuator of the device shown in FIG.

5 is an exploded perspective view of the actuator shown in FIG.

FIG. 6 is an exploded perspective view of the actuator shown in FIG. 5 as viewed from the opposite side.

FIG. 7 is a diagram showing a partial configuration of a second embodiment of the electromagnetic drive device according to the present invention.

FIG. 8 is a diagram showing a partial configuration of a third embodiment of the electromagnetic drive device according to the present invention.

FIG. 9 is a perspective view showing a configuration of a conventional electromagnetic drive device.

10 is a cross-sectional view of the electromagnetic driving device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deck base 2 Spindle motor 3 Magneto-optical disk 3a Cartridge 3b Opening 4 Movable part 5 Fixed optical system 6 Center yoke 8 Side yoke 10 Magnet 11a, 11b Guide rail 20 Carriage 22 Actuator 23 Spring 25 Field coil 27 Coil 28, 29 FPC 32, 33, 36 Bearing 35 Leaf spring 40 Objective lens 41 Lens holder 42 Focus coil 43 Tracking coil 44 Balancer 46, 47 Spring 48 Holding member 50 Base 51 LED 52 PD 53, 54 Yoke 55 FPC 60 Bearing 61 Center yoke 62 Side yoke

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 41/035 G11B 7/085

Claims (3)

(57) [Claims] A movable part having at least one coil, a first magnetic member linearly extending through the coil, and a first magnetic member and a magnetic gap.
A second magnetic member disposed opposite to the first magnetic member, wherein at least a part of the coil is positioned in the magnetic gap, and the movable portion is linearly moved along the first magnetic member.
In the electromagnetic driving device configured to be driven in a manner, the center of the magnetic surface of the first magnetic member is oriented in the direction of the force generated in the coil with respect to the center of the magnetic surface of the second magnetic member. Perpendicular to the magnetic surface of the first magnetic member and
The direction perpendicular to the direction in which the magnetic surface of the second magnetic member faces the magnetic member.
Electromagnetic driving apparatus characterized by being displaced in the direction of exchange. 2. A movable portion having at least one coil, a first magnetic member linearly extending through the coil, and a first magnetic member and a magnetic gap.
A second magnetic member disposed opposite to the first magnetic member, wherein at least a part of the coil is positioned in the magnetic gap, and the movable portion is linearly moved along the first magnetic member.
In the electromagnetic drive device configured to be driven in a shape, the center of the magnetic surface of the second magnetic member is moved with respect to the center of a portion of the coil located in the magnetic gap. Direction , and said first magnetic field
The magnetic surface of the conductive member and the magnetic surface of the second magnetic member face each other.
An electromagnetic drive device, which is shifted in a direction orthogonal to a direction in which the electromagnetic force is applied. 3. A disk recording / reproducing apparatus.
3. The electromagnetic drive device according to claim 1 , wherein the coil
At least in part, an electromagnetic driving device which is characterized by being configured to be positioned within the opening of the disk cartridge containing a disk.