JP2538179Y2 - Linear 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 linear motor, and more particularly to a linear motor suitable for application to, for example, an optical head feed drive linear motor for feeding and driving an optical head in an optical disk drive.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view showing a conventional linear motor for driving an optical head for driving an optical disk apparatus and a configuration in the vicinity thereof, and FIG. 6 is an enlarged sectional view of the linear motor. The optical head 1 can reciprocate along the carriage rail 2 in the disk radial direction. Reference numeral 1a indicates an objective lens. Linear motor 3 for optical head feed drive
Is composed of a rectangular cylindrical linear motor coil 4 attached to the side surface of the optical head 1 and a magnetic circuit 5 for applying a magnetic field to the linear motor coil 4.
A linear motor yoke 6 having portions 6a and 6b located above and below the cylindrical linear motor coil 4 and a center yoke 6c passing through the linear motor coil 4;
And a magnet 7, 8 attached to an upper portion 6a and a lower portion 6b of the linear motor yoke 6. The linear motor coil 4 is, as shown in FIG.
In this configuration, a conductor having a circular cross section is wound around the bobbin 9. As an operation, a current of a predetermined direction and an amount is supplied to the linear motor coil 4 by control means (not shown). Then, by the electromagnetic action of the magnetic circuit 5 and the linear motor coil 4,
The optical head 1 is moved along a carriage rail 2.

[0003]

As described above, the coil 4 in the conventional linear motor is formed in a cylindrical shape by winding a conductive wire around the bobbin 9, but such a cylindrical type requires a large space. Due to the occupancy, there were restrictions on the mounting location.

[0004] For example, in the case of a linear motor for driving the optical head of the optical disk apparatus shown in the figure, the linear motor coil 4 is attached to the lower surface of the optical head 1, for example.
Although it cannot be realized due to the space problem, it is mounted on the side surface. However, in such a configuration, the center of gravity of the optical head 1 and the center of the linear motor drive do not match, and the movable part (optical head 1) There is a problem that an unnecessary moment acts on the linear motor, and the thrust generated in the linear motor cannot be used effectively. In addition, in a configuration using a cylindrical linear motor coil, when trying to make the center of gravity of the optical head coincide with the drive center of the linear motor, it is possible to avoid an increase in the size of the optical disk device and an increase in the weight of the movable portion. It was difficult.

[0005] Japanese Patent Application Laid-Open No. 62-262647 discloses a linear motor in which N planar coils in which the pitches of the folded conductors are formed at equal intervals are mutually shifted in the pitch direction by a length equal to 1 / N of the conductor pitch. , And an insulator is inserted between each of the N planar coils and overlapped,
A linear motor having a stator formed by integrally forming N planar coils and an insulator is disclosed.

However, in the above linear motor, the N planar coils are shifted from each other in the pitch direction by a length equal to one-Nth of the conductor pitch, and the N-phase coils are shifted from the N-phase power source by a predetermined electrical angle pitch. By applying a current, a moving magnetic field is formed on a planar coil.
Instead of applying a DC voltage having the same phase to the N planar coils to form a fixed magnetic field, it is impossible that the conductors of the N planar coils are multiplexed while facing each other. In other words, the individual planar coils are not always in step with each other and generate a maximum magnetic field, and it is difficult to improve the thrust as a linear motor because the space factor of the conductor is low. Also, the stacking of the planar coils originally leads to compactness and weight reduction, but since the effect of improving the thrust cannot be expected so much, in reality, a large number of flat coils must be stacked, and It was impossible to achieve such a compact and lightweight design. Furthermore, since the N-phase coils must be individually supplied with N-phase currents shifted by a predetermined electrical angle pitch, the N-phase coil has a problem that the configuration of the power supply control circuit required for the N-phase power supply becomes complicated. It was something to have.

[0007] The present invention has been made in view of the above circumstances, to reduce the thickness of the linear motor coil, to minimize the restrictions on the mounting location, and to obtain a large linear motor thrust without increasing the size. It is the purpose. It is another object of the present invention to apply the present invention to a linear motor for driving an optical head of an optical disk drive to realize a lightweight movable part and high-speed access.

[0008]

In order to achieve the above object, a linear motor according to the present invention is provided with a plurality of conductors parallel to each other on a film and a common terminal provided at both ends of the plurality of conductors. The film-shaped parallel coil was laminated in plurality with a thin layer of an insulating adhesive interposed therebetween, and the conductors adjacent in the laminating direction were multiplexed almost facing each other in the same direction,
A linear motor coil having the common terminal located on the same side and commonly connected to each other, and a magnetic field forming means disposed to be spaced apart and opposed to a moving path of the linear motor coil and applying a magnetic field to the linear motor coil And characterized in that:

Further, in the linear motor according to the present invention, the film-shaped parallel coil is formed by processing a copper thin plate attached to the film into a lattice shape, and closely arranging conductor patterns having a rectangular cross section with a predetermined gap. It is characterized by becoming.

Further, the linear motor according to the present invention is characterized in that the linear motor coil is disposed on a lower surface of an optical head movably supported on a rail extending in the scanning direction.

[0011]

According to the linear motor coil of the present invention, it is formed thinner than the conventional cylindrical linear motor coil.
In addition, since currents flowing through parallel and parallel conductors provided on the film are in the same direction with respect to the magnetic field, all the conductors can be used as coil effective portions (portions that generate thrust). Therefore, the weight of the linear motor coil is reduced. Furthermore, a magnetic field can be efficiently applied to the effective portion of the coil, a high magnetic flux density can be applied to the coil, and a large linear motor thrust can be obtained.

Further, since the copper thin plate adhered to the film is processed into a lattice shape and the conductor patterns having a rectangular cross section are densely arranged in parallel with a predetermined gap, the net conductor cross sectional area with respect to the entire cross sectional area of the conductor portion is obtained. That is, the space factor of the conductor is improved, and the thrust of the linear motor is increased.

Further, since the linear motor coil can be thinly provided on the lower surface of the optical head, the center of gravity of the optical head and the drive center of the linear motor can be made as close as possible. Without acting, the thrust generated by the linear motor can be used efficiently.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view showing an embodiment in which the linear motor according to the present invention is applied to drive the optical head of an optical disk drive, and FIG. 2 is a flat cable in which the linear motor coil shown in FIG. FIG. 3 is a cross-sectional view of a part of the film-shaped parallel coil shown in FIG. 1, and FIG. 4 is a perspective view showing a modification of the film-shaped parallel coil shown in FIG. .

In FIG. 1, an optical head 1 can reciprocate along a carriage rail 2 in a disk radial direction. Reference numeral 1a indicates an objective lens. A linear motor coil 11 is attached to the lower surface of the optical head 1. In this linear motor coil 11, a film-shaped parallel coil 15 having a large number of parallel conducting wires 13 provided in parallel on a film 12 and a common terminal 14 provided at both ends thereof is sandwiched by a thin layer of an insulating adhesive. It is configured by laminating a plurality of sheets. In this case, the film-shaped parallel coil 16 is configured such that the conductors 13 adjacent to each other in the laminating direction are multiplexed so as to face each other substantially in the same direction. (Not shown). On the other hand, on a chassis 16 below the optical head 1, as a magnetic field generating means, there is provided a flat yoke 17 along the feed direction of the optical head 1 and a similarly flat magnet 18 fixed thereon. The linear motor coil 11, yoke 17, and magnet 18 constitute a linear motor.

The common terminals 14, 14 'on both sides of each film-shaped parallel coil 15 of the linear motor coil 11.
Are individually connected to the flat cable 19 and are drawn out to an external voltage application terminal. As shown in FIG. 3, for example, the film-shaped parallel coil 14 is formed by processing a copper thin plate adhered to the film 12 by photo-etching or the like to form a conductive pattern having a rectangular cross-section densely to form the conductive wire 13. As described above, when the conducting wire 13 has a rectangular cross-section, the ratio of the net conductor cross-sectional area to the total rest cross-sectional area of the conducting wire portion, that is, the space factor of the conducting wire, is improved as compared with a conventional conductor having a circular cross-section. Therefore, the thrust of the linear motor is improved.

In the linear motor having the above configuration, when the linear motor coil 11 is energized, the current flows through the conductor 13. In this case, since the directions of the currents flowing through the respective conductors 13 are all the same with respect to the magnetic field generated by the magnet 18,
All the thrusts acting on the conductor 13 are effective linear motor thrusts.

As shown in FIG. 4, a large number of conducting wires 13 are formed on the film 12 in parallel, and at the same time, the return conductor pattern 20 which is electrically connected to the common terminal 14 'at one end.
May be formed on the same film 12, and two connection terminals connected to the outside may be provided on the same side.

In this case, since the direction of the current flowing through the return conductor pattern 20 is opposite,
Generates a thrust in the opposite direction to cancel the thrust generated in the many parallel wires 13, but since the difference between the respective areas through which the magnetic flux passes is extremely large, the thrust obtained by the many parallel wires 13 is The reverse thrust generated in the conductor pattern 20 is small, and does not hinder the obtaining of a large linear motor thrust.

[0020]

As described above, according to the linear motor of the present invention, a plurality of film-shaped parallel coils are laminated with a thin layer of insulating adhesive interposed therebetween, and the conductive wires adjacent in the laminating direction are connected to each other. Since the multiplexing was performed by multiplexing the common terminals almost in the same direction and connecting the common terminals located on the same side to each other, the linear motor coil was thinned, thereby reducing the mounting position of the linear motor coil. Restrictions can be remarkably relaxed, and there is no coil invalid part (part unrelated to thrust generation), and all can be used as the coil effective part (part generating thrust). The magnetic field can be effectively applied to the effective portion of the coil, and in combination with the thin shape, a magnetic field with a high magnetic flux density can be applied to the coil. Because, an excellent effect, such as it is possible to obtain a large linear motor thrust.

Further, since the film-shaped parallel coil is formed by processing a copper thin plate stuck on a film into a lattice shape and arranging the conductor patterns having a rectangular cross-section densely in parallel with a predetermined gap, the conductor wire portion The net conductor cross-sectional area with respect to the entire cross-sectional area, that is, the space factor of the conductive wire is improved, so that the thrust of the linear motor can be efficiently increased.

Furthermore, since the linear motor coil is disposed on the lower surface of the optical head movably supported by a rail extending in the scanning direction, the linear motor coil has a margin on the lower surface of the optical head by utilizing the thinness of the linear motor coil itself. The center of gravity of the optical head and the drive center of the linear motor can be matched as much as possible, and unnecessary moment does not act on the movable part, so the thrust generated by the linear motor can be used efficiently. In addition, the thrust efficiency of the linear motor can be improved, and the weight of the linear motor coil can be reduced, making it easier to reduce the weight of the movable part. The effective surface area of the linear motor magnet that opposes the linear motor coil on the lower surface of the optical head and applies a magnetic field to it Since it is possible to Te take large,
The effect of increasing the magnetic flux density, further increasing the thrust of the linear motor, and contributing greatly to realizing high-speed access of the optical head is achieved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment in which the linear motor according to the present invention is applied for driving the optical head of an optical disk drive.

FIG. 2 is a perspective view showing a state where the linear motor coil shown in FIG. 1 is attached to an optical head and connected to a flat cable.

FIG. 3 is a sectional view of a part of the film-shaped parallel coil shown in FIG.

FIG. 4 is a perspective view showing a modification of the film-shaped parallel coil shown in FIG.

FIG. 5 is a perspective view showing an example in which a conventional linear motor is applied for driving the optical head of an optical disk drive.

FIG. 6 is a sectional view of a main part of the linear motor shown in FIG. 5;

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Optical head 2 Carriage rail 11 Linear motor coil 12 Film 13 Conducting wire 14, 14 'Common terminal 15 Fim-shaped parallel coil 17 Yoke 18 Magnet

Claims (3)

(57) [Scope of request for utility model registration] 1. A plurality of parallel conductive wires are provided on a film.
Provided in parallel, and common terminals at both ends of the plurality of conductors.
The film-shaped parallel coil provided is replaced with a thin layer of insulating adhesive.
A plurality of wires are interposed and the conductors adjacent in the stacking direction are
In the same direction, they are multiplexed almost directly, and the common terminal is
Lines commonly connected to each other on the same side
A motor coil and the moving path of the linear motor coil.
Are disposed so as to face each other with respect to the linear motor coil.
A linear motor , comprising: a magnetic field forming means for applying a magnetic field . 2. The film-shaped parallel coil according to claim 1 , wherein
The copper thin plate attached to the lum is processed into a grid,
The linear motor according to claim 1 , wherein conductor patterns are densely arranged in parallel with a predetermined gap . 3. The linear motor coil according to claim 1, wherein
On the lower surface of the optical head movably supported by an extending rail
Linear motor according to claim 1, characterized in that disposed.