JP2957880B2 - Rotation detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for controlling a moving operation of a pickup for reading a signal recorded on a disk.

[0002]

2. Description of the Related Art Optical disk players which read signals recorded on a disk using an optical pickup have become widespread, and such a pickup is moved by a driving force of an electric motor in a radial direction of the disk. It is configured to: There are various devices for driving such a pickup.
A technique described in Japanese Patent Application Publication No. 6-205, that is, a technique of linearly driving a pickup by meshing a spur gear with a gear that is driven to rotate by an electric motor is often used.

[0003]

An optical disc player uses a position index information recorded on a disc to detect a position where desired data or the like is recorded and perform a reproducing operation, that is, a search operation. Is configured to be able to perform an operation called ".

Such a search operation is performed by calculating the number of tracks to the target position from the absolute time of the current position and the absolute time of the target position, and moving the optical pickup in accordance with the number of tracks. The moving operation of the optical pickup is configured to control the moving amount by counting the number of signal tracks traversed by using signals obtained from the pickup.

In the method of controlling the moving amount of the pickup by counting the number of signal tracks, it is necessary to perform a control operation based on a signal obtained from a disk, so that the search speed cannot be increased. is there.

An object of the present invention is to provide a rotation detecting device capable of increasing the search speed.

[0007]

According to the present invention, there is provided a rotation detecting device comprising: a rotating disk fixedly press-fitted to a rotating shaft of a motor and provided with a magnet; and a surface of the motor facing the rotating disk. A wiring board made of a magnetic material, the pattern being formed on the surface via an insulating layer, and a magnet provided by the magnet provided on the wiring board and provided on the rotating disk. And a Hall element for detecting a change.

[0008]

According to the present invention, the detecting operation is efficiently performed by providing a Hall element for detecting a magnetic change of a magnet provided on a rotating disk fixedly pressed into a rotating shaft of a motor on a wiring board made of a magnetic material. It is something to do.

[0009]

FIG. 1 is a side sectional view of a principal part showing a rotation detecting device according to the present invention, FIG. 2 is a plan view of a wiring board, FIG. 3 is a side sectional view of a principal part showing a wiring board, and FIG. It is a top view of an important section showing one example of the present invention.

In FIG. 1, reference numeral 1 denotes an electric motor,
A rotary shaft 3 rotatably supported by A and 2B is provided. Reference numeral 4 denotes a rotating disk which is press-fitted and fixed to the rotating shaft 3, is formed of a plastic magnet, has a gear 5 integrally formed, and has an S pole and an N pole as shown in FIG. It is magnetized alternately. Reference numeral 6 denotes a washer press-fitted into the rotating shaft 3, which functions to prevent the adhesive used for fixing the rotating disk 4 from falling down.

Reference numeral 7 denotes a wiring board which is fixedly mounted on a surface 1A of the electric motor 1 facing the rotating disk 4 with screws 8 and is made of a magnetic material. As shown in FIG. A positioning hole 9 is formed to fit with the bearing 2 provided in the first bearing 1. Reference numerals 10 and 11 are mounting holes formed in the wiring board 7, and are provided for fixing the wiring board 7 to the electric motor 1 by fitting the screws 8 described above.

As shown in FIG. 3, the wiring board 7 has a base 7A made of a magnetic material, for example, iron, and the base 7A.
And a pattern 7C formed on the surface of the insulating layer 7B. Reference numerals 12 and 13 denote first and second Hall elements which are soldered to a pattern 7C formed on the wiring board 7, and are arranged at positions facing magnets formed on the rotating disk 4. I have.

The first Hall element 12 and the second Hall element 13 have the same distance from the center of the positioning hole 9 formed in the wiring board 7, that is, the distance from the rotating shaft 3 of the electric motor 1. It is located at a position. With this arrangement, the first Hall element 12 and the second Hall element 12
The Hall element 13 can detect a magnetic change due to the rotation of the rotating disk 4 at the same level.

A magnetic change due to the rotation of the rotating disk 4 is detected by a first Hall element 12 and a second Hall element 13,
An accurate detection output can be obtained by adding and / or subtracting signals obtained from the first Hall element 12 and the second Hall element 13.

Further, since the wiring board 7 on which the first Hall element 12 and the second Hall element 13 are provided is made of a magnetic material, a closed circuit of a magnetic circuit can be formed. As a result, leakage magnetic flux is reduced. Since the number of magnetic fields decreases, the operation of detecting a magnetic change obtained with the rotation of the rotating disk 4 can be performed efficiently and accurately.

FIG. 4 shows an embodiment in which the rotation detecting device of the present invention is incorporated in a pickup driving device. In the figure, reference numeral 14 denotes a cylindrical guide shaft fixed to a fixed substrate (not shown), and reference numeral 15 denotes a pickup support member to which a pickup 16 is fixed. And a spur gear 17 is formed linearly in parallel with the guide shaft 14.

Reference numeral 18 denotes a transmission gear rotatably mounted on a fixed substrate by means of a shaft 19;
A large-diameter gear 18A that meshes with the gear 5 and a small-diameter gear 18B that meshes with the spur gear 17 are integrally formed.

In such a configuration, when a driving current is supplied to the electric motor 1, the rotating shaft 3 starts rotating, so that the rotating disk 4 press-fitted and fixed to the rotating shaft 3 is driven to rotate. When the rotary disk 4 rotates, the gear 5 formed on the rotary disk 4 rotates, so that the rotation force is transmitted to the pickup supporting member via the large-diameter gear 18A and the small-diameter gear 18B constituting the transmission gear 18. It is transmitted to 15 spur gears 17.

The above operation is performed, and the rotational force of the electric motor 1 is transmitted to the pickup supporting member 15, so that the pickup supporting member 15 is slid and displaced in the axial direction of the guide shaft 14. Thus, the pickup supporting member 1
Since the pickup 5 moves while being guided by the guide shaft 14, the pickup 16 fixed to the pickup support member 15 is moved in the radial direction of the disk.
Therefore, a signal recorded on a disk rotated by a turntable (not shown) is picked up by the pickup 16.
Read by.

By the operation described above, the movement of the pickup 16 is performed by the rotational force of the electric motor 1. When the operation is performed, the magnetic change caused by the rotation of the rotary disk 4 causes the first Hall element 12 to rotate. And the second Hall element 13. Since the amount of rotation of the rotating disk 4 is proportional to the amount of movement of the pickup support member 15, that is, the amount of movement of the pickup 16, the amount of movement of the pickup 16 is detected and controlled by detecting the amount of rotation of the rotating disk 4. Can be determined.

The amount of rotation of the rotating disk 4 can be detected based on the detection signals obtained from the first Hall element 12 and the second Hall element 13, so that the disc player can perform a search operation. Is calculated by calculating the number of tracks to the target position and setting the rotation amount of the rotating disk 4 so as to move the pickup 16 by an amount corresponding to the number of tracks. That is, when such an operation is performed, the pickup 16 is moved to the vicinity of the target position. However, since such a moving operation does not use a signal recorded on the disk, the moving operation of the pickup 16 can be performed quickly. As a result, the search speed can be increased.

In the present embodiment, the rotating disk 4 is formed of a plastic magnet, but a ring-shaped magnet is adhered to the lower surface of the rotating disk 4 and the magnet is rotated together with the rotating disk 4. It can also be configured as follows. In this embodiment, the case where two Hall elements are provided has been described, but the number is not limited.

[0023]

According to the rotation detecting device of the present invention, a Hall element for detecting a magnetic change of a magnet provided on a rotating disk fixedly pressed into a rotating shaft of an electric motor is provided on a wiring board made of a magnetic material. Therefore, the magnetic force output from the magnet can be effectively used. Therefore,
Since the detection output of the Hall element can be increased, the detection operation can be performed accurately.

Further, since the rotating disk is formed of a plastic magnet, it is less expensive and can be made thinner than a case where a magnet is separately provided. Further, since the gear for taking out the driving force is formed on the rotating disk, the structure is simplified as compared with the case where the gear is separately provided, and the present invention exerts a very great effect on making the device thinner. It is.

In the present invention, the moving operation of the pickup is performed by the driving force of the rotating disk, and the moving position of the pickup is controlled by the amount of rotation of the rotating disk. It has the advantage that it can be done.

Further, in the present invention, a positioning hole is formed in the wiring board to be fitted with the bearing of the electric motor so that the positioning of the wiring board is performed. You can set up relationships exactly,
In particular, when a plurality of Hall elements are used, it is necessary to make the relationship between all Hall elements and the magnet the same, so that the present invention has a very great effect.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part showing a rotation detecting device of the present invention.

FIG. 2 is a plan view of a wiring board constituting the present invention.

FIG. 3 is a side sectional view of a main part showing a wiring board constituting the present invention;

FIG. 4 is a plan view of a main part showing one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 3 Rotating shaft 4 Rotating disk 5 Gear 7 Wiring board 9 Positioning hole 12 1st hall element 13 2nd hall element 14 Guide shaft 15 Pickup support member 16 Pickup

Claims (6)

(57) [Claims] 1. A rotating disk which is press-fitted and fixed to a rotating shaft of an electric motor and provided with a magnet, and which is attached and fixed to a surface of the electric motor facing the rotating disk and has an insulating layer on the surface. A rotation detecting device comprising: a wiring substrate on which a pattern is formed and made of a magnetic material; and a Hall element provided on the wiring substrate and detecting a magnetic change by a magnet provided on the rotating disk. . 2. The rotation detecting device according to claim 1, wherein a positioning hole is formed in the wiring board so as to fit with a bearing of the electric motor. 3. The rotation detecting device according to claim 1, wherein the rotating disk is formed of a plastic magnet. 4. The rotation detecting device according to claim 3, wherein a gear for extracting driving force is formed on the rotating disk. 5. The rotation detecting device according to claim 4, wherein the pickup is moved by a driving force of a rotating disk. 6. The rotation detecting device according to claim 5, wherein the movement position of the pickup is controlled based on a signal obtained from the Hall element.