JPH05120816A - Optical head driving device - Google Patents

Abstract

PURPOSE:To enable sliding of a carriage without resistance by disposing bearings guided along rails to the center of the carriage and disposing the magnets of the carriage and a base plate in such a manner that the same poles face each other. CONSTITUTION:The rails 2 are fitted to the projecting parts at both ends in the central part of the base plate 1 and while the rails are loosely inserted, the bearings 4A, 4B of the carriage 3 are fitted thereto. The magnets 5A, 5B are fixed to both ends of the carriage 3 in the symmetrical positions holding the rails 2 and the magnets 6A, 6B are fixed onto the base plate 1 in the positions facing these magnets. The magnetic poles of these magnets are so disposed that the same magnetic poles face each other, by which the carriage 3 is held afloat on the plate 1. The carriage 3 is moved without resistance in an X direction by the interaction of the magnetic fluxes of the magnets 23A, 23B and the magnetic fluxes of the yokes 22A, 22B by passing a current to voice coils 21A, 21B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head driving device.

[0002]

2. Description of the Related Art A guide mechanism of a carriage for mounting an optical head used in a conventional optical head driving device is a plan view of FIG. 5A and a sectional view taken along the line FF of FIG. 5A. As shown in FIG. 5 (b), the base plate 31
The carriage 32 is mounted on the top and is configured as follows. That is, a bearing 39 fixed to one end of the carriage 32, a rail 33 for guiding the bearing 39,
34, a bearing 40 attached to one end of the carriage 32 facing the bearing 39 to suppress rotation of the carriage about the rail, and a rail 34 to guide the bearing 40.

Further, in the conventional optical head driving device, in addition to the optical head guide mechanism, the base plate 31
Magnets 37A, B fixed to the yokes, and yokes 38A, B
And the voice coils 35A, B and the yokes 3A, B attached to the carriage 32 that acts electromagnetically with this magnetic circuit. The carriage 32 slides by using the rails 33 and 34 as guides, and the driving force causes an electric current to flow through the voice coils 35A and 35B, whereby the magnetic field of the magnet 37A and the voice coils 35A and 35B.
A driving force is generated in the X-axis direction to move by the induced magnetic field of the yoke 36A due to the electric current.

[0004]

In the above-mentioned conventional optical head driving device, the bearing 39 is attached to one side of the carriage and the bearing 40 is attached to the other end, so that it cannot be formed in a bilaterally symmetrical shape, and the weight is heavy. It has the drawback of being difficult to balance. Further, there is a complicated design problem such that it is difficult to achieve an ideal left-right balance unless consideration is taken of the sliding resistance between the rail and the bearing and the rolling resistance difference between the rail and the bearing. Further, in the conventional optical head guide mechanism, when the bearing mounting angle is deviated and the rolling direction of the bearing is deviated from the moving direction of the carriage, the outer ring of the bearing and the rail are rubbed with each other and the outer surface of the bearing and the rail are damaged. There is also the drawback of letting it go. Therefore, very strict accuracy is required for the mounting angle of the bearing fixed to the carriage, resulting in high assembly cost.

Further, in the above-mentioned conventional optical head drive device, the magnetic circuit and the voice coil are separately attached to the optical head guide mechanism, and the guide portion and the drive portion exist independently. Therefore, it was a factor that complicates the structure.

[0006]

SUMMARY OF THE INVENTION An optical head drive device according to the present invention comprises a carriage on which an optical head is mounted, a bearing which is fitted and fixed to the center of the carriage, and a carriage which guides the bearing. A rail attached to a base plate for moving the first pair of magnets, a first pair of magnets fixed to both ends of the carriage at right angles to the moving direction of the carriage and located symmetrically with respect to the bearing, and fixed to the base plate. A second pair of magnets which face the first magnet with a small gap and have the same magnetic poles on the opposite surfaces, a pair of yokes B whose both ends are fixed to the yoke A of the base plate, and the yoke B A pair of voice coils wound at a predetermined interval and fixed to the carriage, and a third pair of voice coils adhered to the yoke A in the vicinity of the voice coil. And a Gunetto.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. 1 is a block diagram showing a first embodiment of the present invention, FIG.
1A is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 2B is a line B- of FIG.
2B is a sectional view, and FIG. 2C is a partially enlarged view of a C portion of FIG.

Next, the configuration and operation of this embodiment will be described. At both ends of the central portion of the flat plate-shaped base plate 1, there are two projecting portions 1A and 1B with holes.
A round bar-shaped rail 2 is fitted in the hole B. on the other hand,
Bearings 4A and 4B are provided with rails 2 being loosely inserted into both ends of a through hole that vertically cuts through the center of one surface of plate-shaped carriage 3.
I am in conflict. Further, flat magnets 5A and 5B are fixed to both ends of the carriage 3 facing the base plate 1 at symmetrical positions with respect to the rail 2. Long plate-shaped magnets 6A and 6B are attached in parallel with the rails 2 at positions where the protrusions on the base plate 1 face the magnets 5A and 5B. The magnetic poles of the magnets 5A and 6A facing each other are arranged such that the S poles face each other or the N poles face each other as shown in FIG. 2C, and the repulsive force causes the carriage 3 to slightly float on the base plate 1. ing. 1 and 2, the movement of the carriage 3 in the Y direction, Z direction, XY in-plane rotation direction, and ZX in-plane rotation direction is restrained by the rail 2 and the bearings 4A and 4B, and the carriage 3 in the YZ in-plane rotation direction. Is constrained to a position where the repulsive forces of the magnets 5A and 6A and the magnets 5B and 6B are kept in equilibrium. Therefore, the carriage 3 can freely move only in the X direction (axial direction of the rail 2). This movement of the carriage causes the carriage 3 to move in the X direction due to the interaction between the magnetic flux of the magnets 23A and 23B shown in FIG. 2A and the magnetic flux of the yokes 22A and 22B caused by passing a current through the voice coils 21A and 21B. That is, in the first embodiment, the magnets 5A, 6A and 5B, 6B for floating the carriage 3 and the magnets 23A, 23B for moving the carriage 3 are separately formed.

Next, a second embodiment of the present invention will be described with reference to the plan view of FIG. 3 and the sectional views DD and EE of FIGS. 4A and 4B, respectively. .. The second embodiment is different from the first embodiment in that the magnets 11A and 11B of the carriage 9 and the magnets 12A and 12B of the base plate 7 are opposed to each other as shown in FIG. 4A. The carriage 9 is floating. Further, at the same time as this operation, the magnets 12A and 12B cause the yoke 14 by applying a current to the voice coils 15A and 15B.
A magnetic field for moving the carriage in the X direction by the interaction with the magnetic fluxes A and 14B is also formed.

Next, the configuration and operation of the second embodiment will be described. Base plate 7, rail 8, carriage 9, bearings 10A and 10B, magnets 11A and 1 of the carriage 9.
1B and the magnets 12A and 12B of the base plate 7 constitute an optical head guide mechanism. A long plate-shaped yoke 13 in which a long plate-shaped magnet 12A is bonded on one surface
A is fixed to the base plate 7 and has a magnet 12A.
It is connected at both ends with a long plate-shaped yoke 14A sandwiched between them to form a magnetic circuit. Also, a cylindrical voice coil 15A
Is attached to the carriage 9 with the yoke 14A inserted. Similarly, the magnet 12B and the yoke 13
B, 14B and the voice coil 15B are adhesively fixed at symmetrical positions sandwiching the rail 8. When a current is applied to the voice coils 15A and 15B by an external control circuit (not shown), the carriage 9 is formed in the space between the magnet 12A and the yoke 14A and the space between the magnet 12B and the yoke 14B. It is driven in the axial direction of the rail 8 by the electromagnetic action with the magnetic field.

[0011]

As described above, according to the present invention, the bearing for guiding along the rail is arranged in the center of the carriage, and the magnets of the carriage and the base plate are opposed to each other with the same magnetic pole. It has a well-balanced shape and improves the conventional unbalanced structure. In addition, since the bearing that requires extremely strict accuracy in the mounting angle is not used and the number of rails that require machining accuracy is reduced from two to one, the structure can be simplified. Further, the optical head driving device of the present invention has the effect of reducing the number of constituent parts and the number of assembling steps by using the magnet of the guide mechanism as a part of the driving magnetic circuit, thereby reducing the cost of the device. ..

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

2A is a sectional view taken along the line AA of FIG. 1A, FIG. 2B is a sectional view taken along the line BB of FIG. 2, and FIG.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line DD of FIG. 3A and FIG.
It is a -E sectional view (b).

FIG. 5 is a configuration diagram (a) of a conventional optical head driving device and a cross-sectional view (b) taken along line FF in FIG. 5 (a).

[Explanation of symbols]

1,7 Base plate 2,8 Rail 3,9 Carriage 4A, 4B, 10A, 10B Bearing 5A, 5B, 6A, 6B, 11A, 11B, 12A, 1
2B magnets 13A, 13B, 14A, 14B, 22A, 22B
Yoke 15A, 15B, 21A, 21B Voice coil

Claims (2)

[Claims] 1. A carriage on which an optical head is mounted,
A bearing fixed to the central portion of the carriage, a rail attached to a base plate for guiding the bearing to move the carriage, and a bearing fixed to both end portions at right angles to the moving direction of the carriage. A first pair of magnets which are sandwiched and symmetrically positioned, and a second pair of magnets which are fixed to the base plate and face the first magnet with a small gap and have the same magnetic poles on the facing surfaces. , A pair of yokes B both ends of which are fixed to the yoke A of the base plate, a pair of voice coils wound around the yoke B at a predetermined interval and fixed to the carriage, and the voice coil close to the voice coil. York A
And a third pair of magnets adhered to the optical head driving device. 2. The pair of second magnets and the pair of third magnets attached to the base plate are integrally structured to form a pair of magnets. The optical head driving device described.