JP2000090611A - Servo track writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a servo track writer which is highly accurate and has a good settlability and a high reproducibility. SOLUTION: The servo track writer is characterized by comprising a movable stage 11 for holding a head, a linear motor 14 for driving the stage 11 in a movement direction, a gravity guide 12 having a reference face for supporting a direction of gravity of the stage 11, a yaw guide 13 for guiding the stage 11 in the movement direction from one side of the stage 11 by a guide face orthogonal to the reference face, a hydrostatic bearing set to the stage 11 to be opposite to the gravity guide 12 and yaw guide 13, and a pre-load mechanism for applying a pre-load to the hydrostatic bearing. Since the stage 11 is supported, guided in a noncontact manner on two faces, the servo track writer can be realized with a large degree of design freedom while the stage is less deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear drive type servo track writer for recording initial information on a disk-type information recording medium, which has a high recording density, can be positioned at high speed and with high accuracy, and requires less maintenance. It is an object to provide an easy servo track writer.

[0002]

2. Description of the Related Art FIG. 4 is a schematic diagram of a conventional servo track writer using a linear drive system.

A motor 105 for rotating a disk 104 on a base 101 and a positioning device 11 for linearly driving a stage 111 on which a head 104 is mounted.
4 are provided. In this servo track writer, the disk 104 and the head 110 move relatively by the rotational movement of the disk 104 and the linear movement of the head 110, and a track is written on the disk.

FIG. 5 is a schematic view of a guide mechanism of the positioning device.

A guide 112 guides the stage 111 in one axial direction. Reference numeral 121 denotes a hydrostatic bearing, which is provided on four surfaces of the stage 111 facing the guide 112. The static pressure bearing forms a gap between the static pressure bearing 121 and the guide 112 by flowing out air, and supports the stage 111 slidably with respect to the guide 112.

The stage 111 is driven by a ball screw (not shown).

[0007]

The above-described static pressure guide mechanism is a four-sided guide mechanism having four static pressure surfaces. 4
The surface-constrained guide mechanism is excellent in terms of high rigidity, but is heavy and very expensive. Further, it is difficult to design the guide mechanism of the four-plane constraint so as to apply a thrust to the center of gravity of the stage, which is a movable part, when disposing the positioning device. Further, if the thrust is applied to the center of gravity of the stage by sandwiching the stage between the two positioning devices, the entire device becomes heavy and costly, and the control system becomes complicated due to the need to adjust the thrust balance. .
Alternatively, a structure in which a positioning device is arranged between the two guides is also conceivable, but the cost increases and the space increases.

Accordingly, it has been difficult to adopt a hydrostatic bearing guide mechanism in a linear drive type servo track writer.

An object of the present invention is to improve the above-described conventional servo track writer, and an object of the present invention is to realize a servo track writer with high accuracy, good settling, and high reproducibility.

[0010]

According to the present invention, there is provided a servo track writer comprising: a motor for rotating a disk for recording information; a stage device for holding a head and positioning the head; In the servo track writer for recording information on the disk by relatively moving the head and the disk, the stage device,
A stage that holds and moves the head, a linear motor that drives the stage in the direction of movement, a gravity guide having a reference surface that supports the stage in the direction of gravity, and a guide surface that is orthogonal to the reference surface. A yaw guide for guiding the stage in the movement direction from one side of the stage, a static pressure bearing provided on the stage, and opposed to the gravity guide and the yaw guide, and a preload for applying a preload to the static pressure bearing. And a preload mechanism.

It is desirable that the motor and the stage device are provided on a base, and a mechanism for adjusting the inclination of the stage device with respect to the base is provided.

Preferably, the linear motor is detachably attached to the stage device.
It is preferable that the linear motor has a spacer, and the position at which the thrust of the linear motor is generated can be adjusted by the spacer.

Further, it is preferable that the propulsion generated by the linear motor is disposed so as to pass through the center of gravity of the stage.

It is preferable that the stage device has one linear motor.

Further, it is desirable to have a position measuring means for measuring a position of the stage in the moving direction, and it is preferable that the position measuring means is an encoder.

[0016]

FIG. 1 is a perspective view of a servo track writer according to an embodiment of the present invention.

1 is a base. A column 3 for supporting the sub-base 2 is provided on the base. The sub-base holds a motor 5 for driving the disk 4 to rotate. An encoder (not shown) for measuring the rotation angle of the disk 4 is attached to the motor 5.

Reference numeral 11 denotes a stage on which a head (not shown) is mounted and is movable in one axis direction. Reference numeral 12 denotes a gravity guide that supports the stage 11 on a horizontal reference plane and restricts the attitude in the pitching and rolling directions with respect to the stage traveling direction. The gravity guide 12 is made of a magnetic material, and the reference surface is polished. Reference numeral 13 denotes a yaw guide having a guide surface orthogonal to the reference surface of the gravity guide 12, and restricts yawing in the stage traveling direction. Yaw guide 13
Is made of a magnetic material, and the guide surface is polished. Static pressure bearings (not shown) are provided on two surfaces of the stage 11 facing the gravity guide 12 and the yaw guide 13, and are supported in a non-contact manner. The support of the stage by the hydrostatic bearing will be described later.

Reference numeral 14 denotes an electromagnetic linear motor, which drives the stage 11 linearly without contact. Linear motor 14
Has a linear motor stator fixed to be substantially integrated with the gravity guide 12 and a linear motor movable element fixed to be substantially integrated with the stage 11. The linear motor stator is disposed so as to fit into a recess provided in the gravity guide. The linear motor 14 is disposed so as to penetrate the inside of the stage 11.

Reference numeral 16 denotes an encoder for measuring the position of the stage 11. The encoder 16 measures the position of the stage 11 at a position away from the yaw guide 13.
The encoder 16 has an optical or magnetic linear scale and a head as a detection unit. In the case of an optical encoder, the light source of the detection unit is an LED with excellent durability
It is desirable to use In addition, quartz is used as a material of the scale, and highly accurate and stable position information can be obtained. The positioning control of the stage 11 is performed in a closed loop by feeding back the position information of the stage 11 measured by the encoder 16.

Reference numeral 18 denotes a micro head for adjusting a tilt of a stage device for positioning the stage 11 with respect to the base 1. Microheads are provided at three locations, and the height of the stage device is adjusted by adjusting the height with respect to the base at three points. By performing the tilt adjustment of the stage device, the parallelism between the head (not shown) mounted on the stage and the disk 4 can be adjusted. By adjusting the inclination of the head and the disk, the flying height of the head with respect to the disk can be stably maintained.

FIG. 2 shows a static pressure guide mechanism employed in the present invention.

In FIG. 1, reference numeral 21 denotes a static pressure bearing for uniformly blowing high-pressure gas to the opposing gravity guide 12 or yaw guide 13 to maintain a gap and support the stage 11 in a non-contact manner. As the hydrostatic bearing, a solid lubricated porous material polished is used. 23 is a preload mechanism, which has a metal yoke and a magnet. Preload mechanism 23
Generates a suction force between the guide and a guide made of a magnetic material, applies a preload to a gap formed by the hydrostatic bearing, and increases spring rigidity. Further, the stage 11 is controlled by the preload mechanism 23.
Is preloaded in the yaw guide direction, so that the yaw guide 13 supports the stage 11. Therefore, the yaw guide 13 can be guided in a stable manner although it is one-sided. That is, the static pressure bearing 21 and the preload mechanism 23 provided on the stage 11
Are restricted by two surfaces, a reference surface of the gravity guide and a guide surface of the yaw guide.

FIG. 3 is a schematic view of a stage device used in the present invention.

In the figure, the same components as those in the previous figures are denoted by the same reference numerals as those in the previous figure, and therefore description thereof is omitted.

On the stage 11, an arm assembly 10 for holding a head is mounted. Stage 11
And a concave portion is provided in the gravity guide 12 along the traveling direction,
The linear motor 14 is provided in the space configured by this. The linear motor stator is detachably fixed to the gravity guide 12 by screws, and the linear motor mover is detachably fixed to the stage 11 by screws. That is, the linear motor 14 is detachably fixed to the stage device. The linear motor 14 is arranged so as to apply a propulsive force to the center of gravity of the stage. Also, by inserting the spacer 24 into the linear motor movable element and the spacer 25 into the linear motor stator, it is possible to adjust the position of the thrust applied by the linear motor 14 to the stage. The linear motor 14 employs a moving coil system, in which the linear motor mover has a coil and the linear motor stator has a magnet. The current supply to the coil of the linear motor mover is performed by a flexible cable composed of a flat cable (not shown), and the resistance to the operation of the linear motor mover is very small.

According to the servo track writer of the present embodiment, by employing the static pressure guide, the magnetic recording head held by the arm assembly mounted on the stage can be positioned with high accuracy, and the settling time is greatly reduced. You can make it shorter. In addition, since the frictional resistance is reduced by employing the static pressure guide, the reproducibility of the position of the head driven by the stage is greatly improved.

Further, since the guide of the stage is performed from two orthogonal planes, the overall design freedom including the guide mechanism is increased. In particular, when designing a configuration in which the thrust of the linear motor is applied to the center of gravity of the stage, it is easy to design the thrust to be arranged at the center of gravity of the stage with one linear motor. Further, since the support and guide are performed in a non-contact manner from two orthogonal planes, the stage is not deformed because the stage is not excessively restrained.

Further, since the driving force of the linear motor is applied to the center of gravity of the stage, the resonance frequency of the stage can be set high. In addition, it is possible to suppress a change in posture (yaw, pitch, and rolling) with respect to the traveling direction of the stage. Therefore, head positioning control can be performed at high speed.

Further, the linear motor is mounted by disposing a concave portion (groove) near the center of the horizontal static pressure surface along the traveling direction so that the linear motor can be attached and detached without separating the guide mechanism. . Therefore, the maintenance and replacement of the linear motor can be easily performed without separating and re-adjusting the guide mechanism assembled with high precision. Also, even if the weight of the load changes due to the conditions of the magnetic head, disk, etc., and the position of the center of gravity of the stage changes, the thrust generated by the linear motor is adjusted to pass through the center of gravity of the stage by replacing the linear motor spacer. Therefore, a general-purpose servo track writer can be configured.

In addition, since a solid lubricating and porous static pressure bearing is used for the static pressure guide mechanism, even if the supply of gas is stopped, the static pressure surface is less likely to be nicked and scratched. Further, the static pressure guide mechanism eliminates the need for maintenance for a long period of time, thereby improving productivity.

Also, in this embodiment, the linear scale is installed on the stage side and the detection unit is arranged on the fixed unit side, so that the signal cable of the detector is not pulled even if the stage moves, so that the positioning accuracy and settling can be achieved. The effect on time is small, and the reproducibility of the head position is high.

Further, since the linear motor employs a moving coil system, the linear motor mover is small.
The stage, which is a movable part, can be reduced in weight.

In this embodiment, the magnet is used for the preload mechanism. However, the present invention is not limited to this. For example, a suction force by vacuum suction may be used. In this case, the material of the guide is not limited to the magnetic material.

Although the encoder is used for measuring the position of the stage, the present invention is not limited to this. For example, position information measured using a laser interferometer may be fed back.

In this embodiment, a moving coil type linear motor is used. However, the present invention is not limited to this, and a moving magnet type linear motor may be used. In this case, the magnet is fixed to the stage, which is a movable body, so that wiring for current supply is not required,
Highly accurate positioning can be performed.

Further, in the present embodiment, the inclination angle of the stage device is adjusted by adjusting the height at three places by the micro head. However, the present invention is not limited to this. Only two locations are required.

[0038]

According to the servo track writer of the first aspect of the present invention, since the stage is guided from two orthogonal planes, the degree of freedom in designing the servo track writer is increased. In addition, non-contact support from two planes
Since the guide is provided, do not restrain the stage excessively. Therefore, it is possible to realize a highly accurate servo track writer with less deformation of the stage.

According to the servo track writer of the present invention, since the inclination between the head and the disk can be adjusted, the flying height of the head is stabilized and a high-precision servo track writer is provided. be able to.

According to the servo track writer of the third aspect, maintenance and replacement of the linear motor can be easily performed.

Further, according to the servo track writer of the present invention, since it is possible to cope with a change in the weight of the load on the stage, a servo track writer can be used for general purposes.

According to the servo track writer of the fifth aspect, the resonance frequency of the stage can be set high and the change in the attitude can be suppressed low, so that the positioning control of the head can be performed at high speed.

According to the servo track writer of the sixth aspect, a high-speed and high-accuracy servo track writer can be realized at low cost and in a small space.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a servo track writer of the present invention.

FIG. 2 is a schematic diagram of a static pressure guide mechanism employed in the present invention.

FIG. 3 is a schematic view of a stage device used in the present invention.

FIG. 4 is a schematic diagram of a conventional servo track writer using a linear drive system.

FIG. 5 is a schematic view of a guide mechanism of a conventional servo track writer.

[Explanation of symbols]

 Reference Signs List 1 base 2 sub-base 3 pillar 4 disk 5 motor 10 arm assembly 11 stage 12 gravity guide 13 yaw guide 14 linear motor 16 encoder 18 micro head 21 static pressure bearing 23 preload mechanism 24, 25 spacer

Claims (8)

[Claims] 1. A servo for recording information on a disk, comprising: a motor for rotating and driving a disk for recording information; and a stage device for holding a head and positioning the head. In a track writer, the stage device includes a stage that holds and moves the head, a linear motor that drives the stage in a moving direction, a gravity guide having a reference surface that supports the stage in the direction of gravity, A yaw guide that guides the stage in the movement direction from one side of the stage by a guide surface orthogonal to a reference surface; a hydrostatic bearing provided on the stage and provided to face the gravity guide and the yaw guide; A servo track writer comprising a preload mechanism for applying a preload to a hydrostatic bearing. 2. The servo track writer according to claim 1, wherein said motor and said stage device are provided on a base, and have a mechanism for adjusting an inclination of said stage device with respect to said base. 3. The servo track writer according to claim 1, wherein the linear motor is detachably attached to the stage device. 4. The servo track writer according to claim 3, wherein the linear motor has a spacer, and the spacer can adjust a position at which the driving force of the linear motor is generated. 5. The driving force generated by the linear motor is as follows:
5. The servo track writer according to claim 1, wherein the servo track writer is disposed so as to pass through the center of gravity of the stage. 6. The servo track writer according to claim 1, wherein the stage device has one linear motor. 7. The servo track writer according to claim 1, further comprising a position measuring unit that measures a position of the stage in the moving direction. 8. The servo track writer according to claim 7, wherein said position measuring means is an encoder.