JP2538095Y2 - Linear motion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a linear motion device that causes a moving body to perform a predetermined linear motion by a mutual magnetic field action between a permanent magnet and a movable coil.

(Prior Art) A linear motion device is often used for various devices. For example, in an optical pickup device, a linear motion device for moving an optical head straight by a voice coil type linear motor is employed. An example of the linear motion device in the optical pickup device is shown in FIG.

In FIG. 5, a carriage 3 as a moving body is movably mounted on shafts 7 and 7 as guide members via a plurality of rollers 4. The optical head 2 is fixed on the carriage 3 so as to reciprocate integrally with the carriage 3. The optical head 2 is arranged in a region directly below the disk-shaped optical disk 1, and laser light emitted from an objective lens 2 a provided on the upper end surface of the optical head 2 is exposed on the optical disk 1. Irradiation is made in a direction perpendicular to the plane, whereby information is read or written.

A pair of movable coils 5, 5 wound in a hollow rectangular shape are attached to both sides of the carriage 3, and a plurality of yokes 8 for applying electromagnetic driving force to the movable coils 5, 5 are provided. is set up.

The carriage 3 is reciprocated along the shafts 7 and 7. In order to absorb the play between the shaft 7 and the roller 4 during this operation, the carriage 3 should be provided with a holding plate spring 6. The shaft 7 is sandwiched between the rollers 4.

However, in the above-described configuration, the clamping force fluctuates depending on the strength of the holding plate spring 6, and the rattling of the carriage 3 cannot be completely suppressed. If the carriage 3 rattles, for example, as shown in FIG. 6, the light emitted from the optical head 2 to the optical disk 1 is tilted, and the recording / reproducing signal is degraded. Further, as shown by a two-dot chain line in FIG. 7, the carriage 3 may be displaced in the track direction, and the tracking servo may be defective.

Furthermore, if the carriage 3 rattles, the frictional force at the time of movement varies, and as a result, the moving speed of the carriage 3 may become uneven.

To solve such problems, see, for example,
In the apparatus described in Japanese Patent Application Laid-open No. 1 or JP-A-62-109267, an elastic member or a magnetic member for holding the carriage at a predetermined position is newly added, whereby the rattling of the carriage is caused. To make the wear of the motion mechanism uniform and reduce the resonance of the entire system.

(Problems to be solved by the present invention) However, in this conventional device, since new components and mechanisms are added, the number of components is increased, and the reliability is reduced accordingly. ing. There is also a problem that the production cost increases and the size of the device increases.

Therefore, an object of the present invention is to provide a linear motion device capable of obtaining a good linear motion in a small space without adding new parts.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a moving body that carries a transported body and performs a linear motion along a predetermined guide member;
A linear motion device comprising a movable coil attached to the movable body and a permanent magnet for applying a moving force to the movable coil, wherein the movable body is entirely magnetic so as to be attracted to the permanent magnet side. An integral member formed of a body, a part of the surface of the movable body and a permanent magnet are opposed to each other, and a regulating member that regulates movement of the movable body due to an attractive force of the permanent magnet is provided. It is characterized by being.

(Operation) In the means having such a configuration, a magnetic path is formed between the permanent magnets constituting the porcelain circuit of the electromagnetic drive system and the moving body, and the moving body is constantly attracted to the permanent magnet side. With this suction force, the moving body is always maintained in a fitted state without rattling to the guide member,
The restricting member restricts the movement of the moving body due to the attractive force of the permanent magnet. Therefore, even when the driving force from the movable coil acts on the moving body and the moving body reciprocates, the moving body is stably moved without rattling, and a smooth driving state without resonance is obtained. It has become. In particular, since the moving body and the permanent magnet are opposed to each other, the moving body having the head fixedly held in the optical pickup device or the like can be driven stably, and the tracking servo does not have a defect.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, FIG. 2, FIG. 3, and FIG. 4, a rectangular substrate 13 is mounted on a base table 11 through a plurality of columns 12 substantially horizontally. I have. The substrate 13 has a hole 13 formed in a polygonal shape that is long in one direction.
a guide shaft 14 as a guide member along the vicinity of one side edge in the longitudinal direction of the hole 13a.
Is installed. The guide shaft 14 is formed in a circular cross section and has a hole 13 on the upper surface side of the substrate 13.
a is arranged so as to hang in the longitudinal direction, and both ends thereof are fixed to the upper surface side of the substrate 13.

A carriage 15 as a moving body is slidably mounted on the guide shaft. Carriage 15 above
By forming an iron plate material as a magnetic material into an elongated plate shape, as an integral member, the whole is made of a magnetic material, and the bearing boss 15a formed at one longitudinal end thereof is It is slidably fitted to the guide shaft 14. The carriage 15 is disposed so as to be bridged in the short direction of the hole 13a, and a roller 16 rotates at an end portion of the carriage 15 opposite to the fitting portion on the guide shaft 14 side. It is freely supported.
The roller 16 is rotatably mounted on the upper surface side of the substrate 13, whereby the carriage 15 is installed so as to be able to reciprocate in the axial direction of the guide shaft 14.

Further, on the carriage 15, an optical head as a transported body is reciprocated integrally with the carriage 15.
17 is fixed. The optical head 17 is arranged in a region immediately below a disk-shaped optical disk 18.
A laser beam emitted from an objective lens 17a exposed at the upper end of the optical disk 18 is irradiated in a direction perpendicular to the recording surface of the optical disk 18. By forming a light spot on the recording surface of the optical disk 18, information is read or written. The fixed position of the optical head 17 is accurately adjusted so that the orthogonal state between the laser light and the recording surface of the optical disk 18 is maintained with high accuracy.

Further, on the lower surface side of the carriage 15, a movable coil 20 formed by winding into a hollow rectangular shape extending long downward is provided.
Is attached. The movable coil 20 is arranged in the vicinity of the guide shaft 14, and penetrates the hole 13a of the substrate 13 and hangs downward.

On the other hand, an elongated yoke frame-shaped outer yoke 21, an elongated plate-shaped inner yoke 22, and a permanent magnet
23 is attached to the lower surface of the substrate 13 via a spacer 24 in a predetermined positional relationship.

The outer yoke 21 is disposed so as to be offset to one side edge of the hole 13a, and is provided immediately below the guide shaft 14 so as to sandwich the movable coil 20 at the center. The two side plates 21a, 21a in the longitudinal direction of the outer yoke 21 are arranged so as to extend in the axial direction of the guide shaft 14, and the permanent magnets are disposed on the inner surface side portions of the both side plates 21a, 21a. 23, 23 are mounted so as to face each other. The pair of permanent magnets 23, 23 are arranged so that the longitudinal direction thereof extends in the axial direction of the guide shaft 14, and the above-mentioned internal magnet is provided in a predetermined elongated gap formed in the facing portion of the two. A yoke 22 is arranged. Both ends in the longitudinal direction of the inner yoke 22 are fixed to end plates 21b, 21b of the outer yoke 21, respectively.The movable coil 20 is mounted around the outer side of the inner yoke 22 in a loosely fitted state. I have. Therefore, when the movable coil 20 is energized, a mutual magnetic field action occurs between the movable coil 20 and the permanent magnet 23, so that the carriage 15 obtains a predetermined driving force.

In this case, as shown in FIG. 1, a carriage made of a magnetic material is provided directly above the permanent magnets 23.
The magnetic flux B formed on the upper end surface portion of each permanent magnet 23 is
It is configured as a magnetic path that passes through the interior of the device. Therefore, the carriage 15 is always attracted to the pair of permanent magnets 23. The carriage 15 is urged to rotate clockwise in FIG. 1 around the guide shaft 14 by attracting a part of the carriage 15 to the permanent magnet 23 as described above. The roller 16 and the substrate 13 constitute a restricting means for restricting the movement of the carriage 15 by the urging force.

The spacer 24 is made of a non-magnetic resin material so that an unnecessary magnetic circuit is not formed.

In the embodiment having such a configuration, as described above, the permanent magnets 23 constituting the magnetic circuit of the linear motor are used.
The carriage 15 is constantly attracted to the side, and the rollers 16 are pressed against the substrate 13, so that the carriage 15 is always maintained in a state of rattling on the guide shaft. Therefore, even when the driving force due to the mutual electromagnetic action between the permanent magnet 23 and the movable coil 20 acts on the carriage 15 and the carriage 15 reciprocates, the carriage 15 constantly moves on a stable locus without rattling. Thus, the drive is performed smoothly without causing resonance.

The magnetic material constituting the carriage 15 includes:
In addition to the iron plate material as in the above embodiment, a material in which magnetic iron powder is mixed in a mold resin material or the like can be considered.

The present invention is not limited to the optical pickup device as in the above embodiment, but can be similarly applied to various other devices.

(Effects of the Invention) As described above, the present invention provides a moving body on which a transported body is mounted and linearly moves along a guide member, a movable coil attached to the moving body, and an interaction magnetic field action between the movable coil and the movable coil. And a permanent magnet that applies an electromagnetic driving force to the moving body by the moving body, in order to eliminate the rattling of the moving body during linear movement, the moving body is entirely attracted to the permanent magnet side. This is an integral member formed of a magnetic material, wherein a part of the surface of the moving body is opposed to the permanent magnet, and a regulating member for regulating the movement of the moving body due to the attractive force of the permanent magnet is provided. Therefore, since the moving body is an integral member made of a magnetic material as a whole, the moving body requires only one member, so that the number of parts can be reduced and the cost of parts and assembly can be reduced. In addition, the moving body can be stably driven without rattling without adding new parts, and a good rectilinear motion without resonance can be obtained with uniform friction. A linear motion device can be obtained at low cost. In particular, since the moving body and the permanent magnet face each other, for example, when the present invention is used in an optical pickup device or the like, the moving body holding the fixed head can be driven stably.
The occurrence of a defect in the tracking servo can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of an optical head moving device according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are diagrams of the optical head moving device shown in FIG. FIG. 5 is a cross-sectional view, a plan view, and an external perspective view showing the entire structure. FIG. 5 is a cross-sectional view showing a conventional optical head moving device.
6 and 7 are a side view and a plan view showing the state of the optical head being stiff. 14 guide shaft, 15 carriage, 17 optical head, 18 optical disk, 20 movable coil, 21 external yoke, 22 internal yoke, 23 permanent magnet.

Continued on the front page (72) Inventor Toru Kamada 14-888 Ako, Komagane-shi, Nagano Co., Ltd. Inside the Komagane Plant of Sankyo Seiki Seisakusho Co., Ltd. Inside the Komagane Factory (56) References Hikaru 1-79383 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A moving member mounted on the moving member and performing a linear motion along a predetermined guide member; a movable coil attached to the moving member; Wherein the moving body is an integral member formed entirely of a magnetic material so as to be attracted to the permanent magnet side. A linear motion device, wherein a part of the surface and a permanent magnet are opposed to each other, and a restricting member that restricts movement of the moving body due to an attractive force of the permanent magnet is provided.