JPH0519878Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical disc player.

[Summary of the idea]

The present invention consists of a headblock to which an optical head is attached, a guide shaft into which a thrust bearing provided at one end of the headblock is slidably inserted, and a roller rotatably attached to the other end of the headblock. It has a movably placed guide rail and a linear motor consisting of a fixed yoke that has a moving coil and a magnetic plate fixed to the headblock, and the driving force of the linear motor allows the headblock to run stably on the guide shaft and guide rail. In an optical disk player configured to move the optical head in the radial direction of the optical disk, the roller is urged onto the guide rail using the magnetic attraction force of the magnetic plate of the linear motor. By doing so, it is possible to prevent the head block from rotating vertically about the guide shaft and shaking due to vibration or the like.

[Conventional technology]

Conventionally, in an optical disc player, a headblock with an optical head attached thereto is inserted through two guide shafts mounted horizontally and parallel to the chassis, and the headblock is guided by the two guide shafts to allow the headblock to travel. was.

According to this conventional structure, the headblock does not wobble up and down due to vibrations, etc.
Unless the parallelism of the two guide shafts is high, the headblock cannot run smoothly and stably. However, in order to attach the two guide shafts to the chassis in a completely parallel state, both the precision of the parts and the assembly must be high, and
Parallelism adjustment work was also required after assembly, resulting in defects that resulted in low productivity.

Incidentally, the applicant of the present invention has previously filed an earlier application (Japanese Patent Application No. 59-57076) for an optical disc player capable of correcting the above-mentioned defects.

In this prior application, one end of the headblock to which an optical head is attached is inserted through a guide shaft horizontally attached to the chassis, and a roller consisting of a ball bearing rotatably attached to the other end of the headblock is inserted into the chassis. The headblock is placed on a guide rail installed horizontally, and the weight balance of the headblock causes the rollers to press against the guide rail and roll while the headblock is guided by the guide shaft and guide rail and runs. .

According to the structure of this prior application, since there is only one guide shaft, there is no problem with the parallelism accuracy that occurs when two guide shafts are used, and the headblock can run smoothly and stably.

[Problem that the invention attempts to solve]

However, the structure of the prior application is extremely susceptible to vibrations, and if vibrations or shocks are applied in a direction perpendicular to the axial direction of the guide shaft (vertically or horizontally), the weight balance of the headblock will be affected. If it collapses, the roller easily floats above the guide rail, and the headblock rotates up and down around the guide shaft, making it prone to wobbling (particularly at the resonance point, weak acceleration vibrations can also cause this wobbling). That said, a new problem has arisen. In particular, if the headblock rotates up and down due to the above-mentioned vibrations during recording and reproduction of an optical disk, this is a serious problem because recording and reproduction errors will occur.

The present invention has an extremely simple structure that can prevent the headblock from rotating vertically around the guide shaft and rattling due to vibrations, etc., as in the structure of the prior application.

[Means for solving problems]

The present invention consists of a headblock to which an optical head is attached, a guide shaft into which a thrust bearing provided at one end of the headblock is slidably inserted, and a roller rotatably attached to the other end of the headblock. It has a movably placed guide rail and a linear motor consisting of a fixed yoke that has a moving coil and a magnetic plate fixed to the headblock.The headblock is guided by the guide shaft and guide rail by the driving force of the linear motor and travels. In the optical disk player configured to move the optical head in the radial direction of the optical disk, a magnetic member attached to move the head block together with the head block is provided with a gap between the magnetic plate of the linear motor. The headblocks are arranged to face each other and are configured to apply a rotational moment about the guide shaft to the headblock in order to press and urge the rollers onto the guide rail by the magnetic attraction force of the magnetic member by the magnetic plate. It is.

[Effect]

In the present invention, the rollers are constantly and stably pressed onto the guide rail by the rotational moment applied to the headblock by the magnetic attraction force of the magnetic member by the magnetic plate, so that the headblock is prevented by vibration etc. It is possible to prevent rattling caused by vertical rotation around the guide shaft. Moreover, it utilizes the magnetic attraction force of the existing linear motor's magnetic plate, and simply attaches a magnetic member such as an iron plate to the magnetic plate with a gap in between so that it moves together with the headblock. The structure is extremely simple since it does not use any special pressing mechanism to press the rollers onto the guide rail.

〔Example〕

An embodiment of an optical disc player to which the present invention is applied will be described below with reference to the drawings.

First, a headblock 2 and a turntable 3 are mounted on a chassis 1, and the headblock 2 is used for recording (writing) and/or reproduction (reading) by irradiating a laser beam onto an optical disk and receiving the reflected light. An optical head 4 is attached. Then, an optical disk (not shown) is mounted horizontally on the turntable 3, and the head block 2 moves the optical head 4 in the radial direction of the optical disk (in the direction of arrow a in FIG. 2), thereby recording or recording data on the optical disk. The playback is configured to take place.

Next, the headblock 2 is placed in a horizontally elongated opening 5 provided in the chassis 1. A thrust bearing 6 provided at one end 2a of the headblock 2 is slidably inserted into a guide shaft 7 installed horizontally on the chassis 1, and rotatably attached to the other end 2b of the headblock 2. A roller 8 made of a ball bearing is rotatably placed on a guide rail 9 provided horizontally on the chassis 1. Therefore, the head block 2 is guided by the guide shaft 7 and the guide rail 9 (however, the rollers 8 roll on the guide rail 9) and runs horizontally in the direction of arrow a, so that the optical head 4 is moved in the radial direction of the optical disk. is configured to be moved to

Next, a linear motor 10 is used to drive the headblock 2. This linear motor 10
has three horizontal yoke plates 11a, 11b, 11c spaced apart from each other, and a pair of upper and lower magnetic plates 12a, 12b are fixed horizontally to the vertically opposing surfaces of the upper and lower yoke plates 11a, 11c. A moving coil 15 is fixed to the side surface of the head block 2 via a coil holder 14 and is disposed between a pair of upper and lower magnets 12a and 12b across the upper and lower sides of the intermediate yoke plate 11b. It is structured accordingly. Note that the fixed yoke 13 is fixed to the lower part of the chassis 1,
Both magnetic plates 12a and 12b are magnetized with the same polarity along the moving direction of the moving coil 15 (the direction of arrow a), and are integrated with the moving coil 15 by the magnetic driving force generated by energizing the moving coil 15. The head block 2 is then driven in the direction of arrow a in FIG.

Next, an optical encoder 17 for detecting (tracking) the position of the optical head 4 is attached to the side of the linear motor 10 in parallel. This optical encoder 17 includes a moving coil 15
A long and movable reference slit plate 18 is moved horizontally in the direction of arrow a together with the reference slit plate 18, and a reference slit plate 18 is placed on the upper surface of the reference slit plate 18 and slid relatively on the upper surface of the reference slit plate 18. It is composed of a fixed auxiliary slit plate 19 that can be moved. The reference slit plate 18 is fixed horizontally on a long movable plate 20 made of an angle member fixed horizontally to the side surface of the coil holder 14, and the auxiliary slit plate 19 is attached to a fixed member such as a printed circuit board. It is attached to the fixed plate 21 which is fixed. The relative movement between the reference slit plate 18 and the auxiliary slit plate 19 is determined by the light emitting element 22 and the light receiving element 23, which are arranged above and below the slit plates 18 and 19 and attached to the fixed plate 21. The optical head 4 is detected and the position of the optical head 4 is detected.

Note that the roller 8 is rotatably attached to the tip of a support shaft 24 that is perpendicular to the guide shaft 7, and the head block 2 is rotated largely around the guide shaft 7 in the direction of arrow b in FIG. An overturn prevention plate 25 for preventing overturning is attached to the chassis 1 and arranged along the upper part of the roller 8.

However, in the present invention, a magnetic member 27 such as an iron plate is fixed onto the movable plate 20, which is moved together with the head block 2 in the direction of the arrow a, using screws 28, etc., and this magnetic member 27 is attached to the linear motor 10.
horizontally inserted under the upper magnetic plate 12a of the fixed yoke 13 within the movement space of the moving coil 15 to create a gap 29 in the upper magnetic plate 12a.
They are placed opposite to each other.

Therefore, according to the present invention, as shown in FIG. 1, the upward magnetic attraction force _F1 of the magnetic member 27 by the upper magnet 12a always acts, and the magnetic attraction force
_F1 is transmitted to the headblock 2 via the moving plate 20 and the coil holder 14, and a rotational moment M in the direction of arrow c about the guide shaft 7 is constantly applied to the headblock 2. The rotating moment M causes the roller 8 to be constantly pressed onto the guide rail 9 by a downward pressing force _F2 .

Therefore, while the headblock 2 is traveling in the direction of the arrow a in FIG. It will roll around. As a result, the above-mentioned optical disk recording,
During playback, even if vibrations or shocks are applied in a direction perpendicular to the axial direction of the guide shaft 7 (vertical direction or horizontal direction in FIG. 1), the rollers 8 will not move against the guide rail 9.
It is possible to prevent the head block 2 from floating upward, and to prevent the head block 2 from rotating around the guide shaft 7 in the direction of arrow b in Fig. 1 and wobbling. Playing head block 2
can run extremely smoothly and stably from beginning to end in the direction of arrow a in FIG.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various effective changes can be made based on the technical idea of the present invention.

For example, the magnetic member 27 may be made of a material other than an iron plate, and the mounting position and direction of the magnetic member 27 on the magnet plate 12a etc. can be changed as appropriate. It is possible to install it directly.

Furthermore, the present invention is applicable to various types of optical disc players that record and/or reproduce various types of information.

[Effect of idea]

This invention can prevent the headblock from rotating up and down around the guide shaft due to vibrations, etc., and causing wobbling, which may occur during recording and playback and cause errors in recording and playback. It has extremely high vibration resistance and reliability that can prevent such problems from occurring.

Moreover, the structure is extremely simple, and the purpose can be achieved by simply adding one magnetic member such as an iron plate, and the increase in weight of the headblock due to the addition of the magnetic member can be ignored.
Furthermore, the magnetic member maintains a non-contact state with respect to the magnetic plate, and the addition of the headblock to the running can be ignored. Therefore, not only does the access speed of the optical head not decrease due to the movement of the headblock, but also the access servo becomes easy. In addition, as shown in the example, the magnetic member can be placed within the movement space of the moving coil of the linear motor, so the space factor etc. is very good, miniaturization is possible, and the magnetic member can be installed easily. (Production) is also very simple and low cost.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a sectional view of the main part taken along the arrow II in Fig. 2, and Fig. 2 is a perspective view of the whole with a part cut away. be. In the symbols used in the drawings, 2... head block, 4... optical head, 6... thrust bearing, 7... guide shaft, 8... roller, 9... guide rail, 10... linear motor, 12a... Magnetic plate, 13... fixed yoke, 15... moving coil, 27... magnetic member, 29... gap,
_F1 ...Magnetic attraction force, _F2 ...Pushing force, M...Rotational moment.

Claims (1)

[Scope of claim for utility model registration] A head block to which an optical head is attached,
A guide shaft in which a thrust bearing provided at one end of the headblock is slidably inserted, a guide rail on which rollers rotatably mounted on the other end of the headblock are rotatably mounted, and a guide shaft on the other end of the headblock. The optical head is moved in the radial direction of the optical disk by moving the head block guided by a guide shaft and guide rail using the driving force of the linear motor. In the optical disc player configured to be movable, a magnetic member attached to be moved integrally with the head block is arranged to face the magnetic plate of the linear motor with a gap therebetween, and the magnetism of the magnetic member by the magnetic plate is An optical disk player characterized in that the head block is configured to apply a rotational moment about the guide shaft by suction force to press and urge the roller onto the guide rail.