JP2654391B2 - Disk unit - Google Patents

Description

The present invention relates to a disk drive, and more particularly, to a head moved by a drive motor, an encoder for detecting an actual position of the head, and a drive motor driven according to the head position. And a control unit for generating a force.

2. Description of the Related Art Such a disk device, for example, a porcelain disk device, is widely used in electronic devices such as computers. At present, 1 mega type disks are mainly used in floppy disk devices, but 2 mega type, 10 mega type or higher density disks have begun to be used. 5-10
In order to perform ultra-high-density recording and reproduction of a mega type, a mechanism for controlling the head position with high precision corresponding to that is required.

In such a disk drive, a voice coil motor has recently been used as a drive motor because of its low cost. When a boil coil motor is used as a drive source of a head, an encoder is used to detect a moving amount of a head or a head carriage moved by a voice coil motor to control a relative position of a disk and a head. .

In such an encoder, for example, a photo-interrupter composed of two pairs of light-emitting and light-receiving elements is used to position the head at a position exactly corresponding to the track position of the disk, and a signal from this light-receiving element is obtained. Then, the phase is discriminated and the reversible counter counts forward and reverse, and the voice coil motor is driven until the count value reaches a predetermined value to control the positioning of the head at a position exactly corresponding to the track position of the disk. .

[Problems to be Solved by the Invention] However, in such a conventional disk drive, when the head is stopped, the voltage input to the drive motor is zero, thereby reducing the driving force of the drive motor. Although the head is stopped, the signal actually input to the drive motor does not become zero due to the deviation of the reference voltage of the electronic circuit constituting the control system, the offset of the control system, the fluctuation of the power supply voltage, etc. The motor may not stop.

Therefore, the present invention has been made in view of such a point,
An object of the present invention is to provide a disk device capable of easily and surely adjusting an offset generated in a control system of the disk device.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is configured such that when a head stop signal value input to a drive motor is deviated from a predetermined signal value due to an offset of the control means, the control means A configuration is employed in which the offset value is adjusted by changing the input signal to the drive motor until the movement of the head detected by the encoder stops.

[Operation] In such a configuration, since the offset voltage of the control system is adjusted by the movement of the encoder for detecting the actual position of the head, the offset voltage of the analog system of the control device is easily and reliably adjusted. It becomes possible to do. Such adjustment of the offset value is automatically performed immediately after the operation of the disk device or at regular intervals during the operation.

[Examples] Hereinafter, details of the present invention will be described based on examples shown in the drawings. In the following description, the disk device will be described using a magnetic disk device as an example.

The disk device shown in FIGS. 1 and 2 has a boil coil motor (VCM) 10 as a drive source, and a yoke 12 of the voice coil motor 10 is provided with a mover 16 having a magnet 14 and a coil 16a. ing. A head carriage 18 is integrally attached to the mover 16, and the coil 16
When a current is applied to a, the moving element 16 is moved by interaction with the magnetic field of the magnet 14, and the head carriage 18 is moved integrally therewith. A head arm 20 is integrally attached to the head carriage 18. The head arm 20 penetrates the carriage 18 in the moving direction of the carriage and is guided by a pair of guide bars 22 and 22 fixed to the apparatus, and seeks in a direction approaching to and away from the center of the disk 24, and Can be moved to a predetermined track position. The head arm 20 is provided with a pair of recording / reproducing heads 26. As is well known, information is recorded on and read from or erased from both sides of the disk by the head 26.

Further, a position detecting device, for example, an encoder 28 is provided in parallel with the guide bar 22. The encoder 28 is inserted into a guide notch 18a formed in the head carriage 18, and is connected to the device via an elastic member. It is fixed to. Slits 28a are formed at equal intervals in the encoder 28, and light emitted from a light emitting element of a photo interrupter, which will be described later, disposed in the head carriage 18 is received by the light receiving element via the slit, and the slit By counting the number, the moving amount of the moving element 16 and the head carriage 18 integrated therewith, that is, the moving amount of the head 26 can be detected.

In the case of the present embodiment, the encoder 28 is a head carriage
At the approximate center of 18, the head 26 is arranged near the moving center line M of the head 26 along the head moving direction. And encoder 28
Photo interrupter on the head carriage 18
30 are installed. This Ofoto Interrupter 30
As shown in FIG. 3, one light emitting element 130 and three corresponding light receiving elements 132, 134, and 136 are provided to detect the slit of the encoder that has passed with the movement of the head carriage 18. Thus, the moving amount of the head carriage, that is, the moving amount of the head 26 is detected. Here, the bottom light receiving element 136 is the track 0 of the head 26.
It is for detecting the 0 position and is arranged in relation to a slit 28a for the track 00 provided in the encoder 28.

The two light receiving elements 132 and 134 are arranged with a predetermined phase shift of, for example, 90 ° with respect to the slit cycle, and generate signals φA and φB shifted by 90 ° from each other as shown in FIG. Input to the reversible counter 50. In FIG. 4, the microcomputer 51 compares the count value obtained from the reversible counter 50 with the value corresponding to the target track position of the head 26.
The value is converted to an analog value via a converter 52 and input to the voice coil motor 10 via a power amplifier 53,
The boil coil motor is driven to move the head to a predetermined target track position.

In such a configuration, when the count value corresponding to the target position in the microcomputer 51 matches the count value obtained by the reversible counter 50 with the movement of the encoder 28, the A output of the DA converter becomes 2.5V, for example. At this time, the output current of the power amplifier 53 becomes zero, and the power for driving the boil coil motor disappears.

However, the output of the power amplifier does not become zero and the voice coil motor cannot be stopped due to a deviation of the reference voltage of the DA converter 52, a DC offset of the power amplifier, a fluctuation of the power supply voltage, and the like.

In such a case, the microcomputer 51 has a reversible counter.
Read the contents of 50 and read the current position of the head or the movement of the head. The microcomputer 51 is DA
The point at which the value of the reversible counter 50 does not change while gradually changing the digital value output to the converter 52 will be found. That is, the point at which the input voltage to the boil coil motor is lost and the driving force disappears is found, and the value obtained in this way is set to a new origin. In this way, the voltage value output from the microcomputer at the time of the stop command is a value different from the previous one, that is, a value obtained by adjusting the offset value thereafter, and after this offset adjustment, the power amplifier 53 outputs The output voltage value is zero, and the voice coil motor can be stopped at a predetermined position.

Such adjustment of the offset value can be automatically performed immediately after the operation of the porcelain disk or at regular intervals during the operation.

[Effects of the Invention] As will be apparent from the above description, according to the present invention, the offset voltage appearing in the control system is adjusted by the movement of the encoder for detecting the actual position of the head, so that it is simple and reliable. It becomes possible to adjust the offset value.

[Brief description of the drawings]

1 and 2 are a top view and a perspective view of a disk device used in the present invention, FIG. 3 is a perspective view showing an embodiment of a photo interrupter of an encoder, and FIG. 4 is a circuit diagram for controlling a head position. It is a block diagram. 28 Encoder, 50 Reversible counter 51 Microcomputer 52 DA converter 53 Power amplifier

Claims (2)

(57) [Claims] A head moved by a drive motor;
In a disk drive comprising: an encoder for detecting an actual position of a head; and control means for generating a driving force on a drive motor in accordance with the head position, a head stop signal value input to the drive motor has a predetermined value based on an offset of the control means. If there is a deviation from the signal value,
The control means changes the input signal to the drive motor until there is no movement of the head detected by the encoder,
A disk device for adjusting the offset value. 2. The disk device according to claim 1, wherein the offset value is automatically adjusted immediately after operation of the disk device or at regular intervals during operation.