JPH11185445A - Centering device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve centering for maintaining a disk at fixed intervals to the axis of a shaft or the like by providing at least a plurality of sets consisting of two actuator units with a member that can be straightly moved to a position opposing the disk each other, and can be brought into contact with the disk. SOLUTION: A rod 10a is moved in the positive direction of an x axis until the tip of the rod 10a is brought into contact with a disk and the inside edge of the disk is brought into contact with a hub. Then, a rod 10c is moved in the negative direction of the x axis, and a position x1 of the rod is obtained when the tip of the rod 10c is brought into contact with the disk. The rod 10a is separated from the rod 10c. When the rod 10c is moved in the negative direction of the x axis, the tip of the rod 10c is brought into contact with the disk, and, furthermore, the inside edge of the disk is brought into contact with the hub, a position x2 of the rod is obtained. (x1+x2)/2 becomes the target position of the rod 10c. In the same manner, the target position of a rod 10d is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centering device for centering a disk on a hub (shaft), and more particularly, to writing a servo track information on a disk mounted on a magnetic disk device. The present invention relates to a centering device suitable for centering and mounting work.

[0002]

2. Description of the Related Art Conventionally, servo track information is written on a disk which is a recording medium of a magnetic disk device. Normally, in a state where the magnetic disk device is assembled and completed, the head in the device is positioned by a length measuring device to write servo track information. However, this writing operation has the following problems.

First, since the servo track information is written using the head in the magnetic disk device, the accuracy of the servo track information cannot be improved. Therefore, it is difficult to cope with high density. Second, since all the heads of the magnetic disk drive are used to write the servo track information on all the disks, the operation takes time. Therefore, the cost for writing servo track information increases with mass production of disks.

In order to solve the first problem, there has been proposed a system in which servo track information is written on one disk using a dedicated servo track information writing device, and this disk is incorporated in a magnetic disk device. . In this method, since the servo track information is written on a large number of disks, each one of which is mounted on each magnetic disk device, the above-mentioned second problem is also solved at the same time.

[0005]

However, in the conventional method, the eccentricity when the disk is mounted on the hub (shaft) of the servo track information writing device and the disk on which the servo track information is written are transferred to the hub of the magnetic disk device. Eccentricity when mounting is a problem. In general, between the hub and the center circular opening of the disc,
A gap of about 50 to 100 μm is provided. If there is no eccentricity, there is an equal spacing between the hub and the disk opening.
If eccentricity occurs in either the case where the disk is mounted on the writing device and the servo track information is written or the case where the disk is mounted on the magnetic disk device, when the disk is mounted on the magnetic disk device, the servo track information is not read. The written locus becomes eccentric with respect to the shaft of the disk device. For this reason, it is necessary to operate the head for writing / reading information eccentrically with respect to the shaft, which deteriorates characteristics. Further, if the disk is installed eccentrically with respect to the shaft, when the shaft is rotated, vibrations due to the mounting eccentricity occur, and the characteristics are deteriorated.

In order to reduce the eccentricity, the above gap may be reduced. However, when the gap is reduced, the accuracy required for the parts is increased, which not only increases the cost but also causes a problem that the fitting operation becomes difficult.
This problem is not unique to a magnetic disk drive, but also occurs when a disk is mounted on a shaft and requires centering.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a centering apparatus and a method capable of centering a disk with respect to an axis such as a shaft while maintaining a constant gap.

[0008]

According to a first aspect of the present invention, there is provided a centering device for centering a disk on a shaft (corresponding to a hub 14 in an embodiment described later) in a position opposed to the disk. (A rod 10a-1 of the embodiment)
The centering device is characterized by having at least a plurality of sets of two actuator units having a value of 0d (a set including the actuator units 16a and 16c and a set including the actuator units 10b and 10d in the embodiment). The disk can be centered while maintaining a constant gap with respect to the axis by a plurality of actuator units.

According to a second aspect of the present invention, there is provided an example of an arrangement of the actuator units, wherein the plural sets of actuator units of the first aspect are respectively positioned on straight lines passing through the center of an axis and extending in different directions. It is characterized by doing. According to a third aspect of the present invention, there is provided a configuration for setting an operation mode of the centering device according to the first or second aspect, wherein a mode switching unit (1) capable of selecting a control mode of the actuator unit according to a centering situation. A mode switch 83 and a control circuit 94 in an embodiment described later) and control means for controlling the actuator unit in a selected predetermined control mode (corresponding to a control circuit 94 in an embodiment described later). It is characterized by the following.

A fourth aspect of the present invention provides a specific example of the operation mode according to the third aspect, wherein the selected control mode is a position control mode for performing high-speed position movement, or It is characterized in that either one of an output suppression mode (corresponding to a current suppression mode of an embodiment described later) for performing low-speed position movement by suppressing the speed and acceleration is set.

According to a fifth aspect of the present invention, there is provided the centering device according to any one of the first to fourth aspects, wherein the centering device comprises a first and a second centering device.
And in each of the first and second sets, the two actuator units have first and second rods respectively constituting the member, and in the first set, the first and second rods
The position of the second rod in a state where the second rod is in contact with the outer periphery of the disk while the inner rod of the disk is in contact with the disk and the inner periphery of the disk is engaged with the shaft is x1, and the position of the second rod is x1. The position of the second rod in contact with the disk and the inner periphery of the disk engaged with the shaft is x2, and in the second set, the first rod abuts on the disk and the inner periphery of the disk is on the shaft. The position of the second rod in a state where the second rod is in contact with the outer periphery of the disk in the engaged state is defined as y1,
When the position of the second rod in a state where the rods of the second set are in contact with the disk and the inner periphery of the disk is engaged with the shaft is defined as y2, the disk is set to (x1 + x2) / 2, (y
The centering is performed at a centering position of (1 + y2) / 2. It defines a specific example of centering.

According to a sixth aspect of the present invention, the process of contacting each set of rods with the disk and the process of centering at the centering position according to the fifth aspect are executed in an output suppression mode. I do. This enables fine adjustment of the rod, and improves the accuracy of centering. According to a seventh aspect of the present invention, there is provided a motor in which each of the actuator units according to the fifth or sixth aspect can be controlled by a current supply amount (corresponding to each motor of an embodiment described later).
In the output suppression mode operation, the current supplied to the motor is suppressed to adjust the moving speed and acceleration of each set of rods. It defines a specific example of a method for finely adjusting the rod.

According to an eighth aspect of the present invention, in the processing for centering a disk at the centering position by each set of rods according to any one of the fifth to seventh aspects,
The present invention is characterized in that a current supplied to a set for performing centering in advance is smaller than a current supplied to a set for performing centering in the succeeding manner. It defines a specific example of centering when centering by each set of rods is not performed simultaneously.

According to a ninth aspect of the present invention, in the processing for centering a disk at the centering position by each set of rods according to any one of the fifth to seventh aspects,
The current supplied to the set for performing the centering in advance and the set for performing the centering in the succeeding state are fixed, and after the completion of the preceding centering, the rod is retracted from the abutting disk, and the subsequent centering is performed. Item 8. A centering device according to any one of Items 5 to 7. A specific example of centering different from claim 8 in the case where centering by each set of rods is not performed at the same time is defined.

According to a tenth aspect of the present invention, in the centering device according to any one of the first to ninth aspects, a difference between a movement amount input to the actuator unit and an actual movement amount of the member is allowed. It is characterized by having first means (corresponding to the host computer 26 of the embodiment) for judging that the movement of the member has stopped when the deviation amount becomes larger than the deviation amount. The operation of the member (the rod in the embodiment) can be reliably and easily detected.

According to an eleventh aspect of the present invention, in the centering device according to the tenth aspect, the position information of the member at the time when it is determined that the movement of the member has stopped is output.
(Corresponding to the encoder 19c of the embodiment). Position information of the member (rod) can be reliably obtained. According to a twelfth aspect of the present invention, in the centering device according to any one of the first to eleventh aspects, the plurality of sets of actuator units are multilayered in an axial direction and are radially arranged around an axis. (The configuration of the embodiment shown in FIG. 11). By radially arranging, each layer of the multilayered disk unit can be efficiently centered.

According to a thirteenth aspect of the present invention, in the centering device according to any one of the fifth to ninth aspects, each of the first rods of the first set and the first rods of the second set is provided. A centering position is obtained, and means is provided for verifying whether centering has been correctly performed based on the centering positions of all the rods. The quality of centering can be reliably and easily verified.

The invention according to claim 14 is characterized in that the disk is a recording medium. As a result, servo track information and the like can be written in a state where the disk is correctly centered, and when the disk is mounted on each magnetic disk device, the disk can be securely mounted in a centered state. The centering method according to claim 15 is a centering method for centering a disk with respect to an axis, wherein a member capable of moving straight to a position facing each other with respect to the disk and abutting against the disk is provided.
The centering is performed by using at least a plurality of sets each including one actuator unit (corresponding to FIGS. 16, 17, and 18 of embodiments described later). The disk can be centered while maintaining a constant gap with respect to the axis by a plurality of actuator units.

A centering method according to a sixteenth aspect is characterized in that:
16. A process for setting an operation mode of the centering method according to claim 15, wherein the step of selecting a control mode of the actuator unit in accordance with a centering situation; and the step of selecting the control mode of the actuator unit in the selected predetermined control mode. (FIG. 16, FIG. 17, FIG.
8).

A centering method according to a seventeenth aspect is characterized in that:
17. A specific example of the operation mode according to claim 16, wherein the selected control mode is a position control mode for performing high-speed position movement or a low-speed position movement by suppressing speed and acceleration. (A), (b), (c), (c), (c), (c), (c), (c), (c), (c), (c), (c), and (c).

A centering method according to claim 18 is
The centering method according to any one of claims 15 to 17, further comprising a first and a second set of two actuator units, wherein each of the first and the second sets constitutes the member. A first rod having a first rod in contact with the disk and a second rod abutting on the outer circumference of the disk with the inner circumference of the disk engaged with the shaft in the first set; The position of the second rod in the state is x1, the position of the second rod in the state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is x2, and in the second set, A second rod in a state in which the first rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft, and a second rod is in contact with the outer periphery of the disk.
When the position of the second rod is y1 and the position of the second rod in a state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is y2, the disk is ( It is characterized by centering at the centering positions of (x1 + x2) / 2 and (y1 + y2) / 2 (corresponding to FIGS. 16, 17 and 18 of embodiments described later). This defines a specific example of the centering method.

A centering method according to claim 19 is
19. A process in which each set of rods abuts on a disk and a process of centering at the centering position according to claim 18 are executed in an output suppression mode (see FIGS. 16 and 17 of embodiments described later). , FIG. 18). This enables fine adjustment of the rod, and improves the accuracy of centering.

The centering method according to the twentieth aspect is characterized in that:
The actuator unit according to claim 18 or 19,
Each has a motor that can be controlled by the amount of current supplied,
In the output suppression mode operation, the moving speed and the acceleration of each set of rods are adjusted by suppressing the current supplied to the motor (see FIG.
17 and 18). It defines a specific example of a method for finely adjusting the rod.

A centering method according to claim 21 is
21. In the process of centering a disk at the centering position by each set of rods according to any one of claims 18 to 20, a current supplied to a set which performs centering in advance is supplied to a set which performs subsequent centering. It is characterized in that it is smaller than the current (corresponding to FIGS. 17 and 18 of the embodiments described later). It defines a specific example of centering when centering by each set of rods is not performed simultaneously.

A centering method according to claim 22 is
21. A process for centering a disk at the centering position by each set of rods according to any one of claims 18 to 20, wherein a current to be supplied to a set for performing centering in advance and a set for performing centering thereafter is fixed. After the completion of the preceding centering, the rod is retracted from the abutting disk, and the subsequent centering is performed (corresponding to FIGS. 16 and 18 of embodiments described later). A specific example of centering different from claim 21 when centering by each set of rods is not performed at the same time is defined.

[0026]

FIG. 1 is a diagram for explaining the principle of a centering apparatus and method according to the present invention. The illustrated centering device comprises four rods 10a, 10b, 1
0c and 10d. Rods 10a and 10c are hub 1
4 and the disk 12, and the rods 10 b and 1
0d is similarly opposed. Rods 10a and 10c are x
The rods 10b and 10d are movable in the axial direction, and are movable in the y-axis direction orthogonal to the x-axis. Rod 10a ~
The leading end of 10 d can be in contact with the outer periphery of the disk 12. Using these four rods 10a to 10d, the centering position of the disk 12 with respect to the hub 14 is detected as shown in FIG. 2, and the centering is executed as shown in FIG. The hub 14 is set on a shaft (a shaft 13 described later) of the centering unit.

First, the initial state (rod 10a) shown in FIG.
-10d are all remote from disk 12)
As shown in FIG. 2A, the tip of the rod 10a contacts the disk 12, and the inner edge of the disk 12 is
The rod 10a is moved in the positive direction of the x-axis until the rod 10 comes into contact with the rod 4. Next, as shown in FIG.
Is moved in the negative direction of the x-axis, and the tip of the
The position x1 of the rod when it abuts on is determined. Next, as shown in FIG. 2C, the rods 10a and 10c are separated from the disk 12. Then, as shown in FIG. 2 (d), the rod 10c is moved in the negative direction of the x-axis so that the tip of the rod 10c contacts the disk 12, and the inner edge of the disk 12 contacts the hub 14. Is determined.
Then, (x1 + x2) / 2 is the target position of the rod 10c. The target position of the rod 10c is a position at which the rod 10c is moved to these coordinates during a centering operation described later with reference to FIG.

Similarly, the rods 10b and 10d are moved to determine the target position (y1 + y2) / 2 of the rod 10d. Then, the centering operation shown in FIG. 3 is performed. First, as shown in FIG. 3A, the rod 10c is moved to the target position (x1 + x2) / 2, and the rod 10d is moved to the target position (y1 + y2) / 2. Then, as shown in FIG. 3B, the remaining rods 10a and 1
0b is brought into contact with the disk 12. As a result, the disk 12 is correctly centered with respect to the hub 14. That is, the distance between the opening of the disk 12 and the hub 14 is equal at any point.

If the disk 12 is a disk for writing servo track information, the disk 12 can be positioned on the hub 14 of the servo track information writing device without eccentricity. Then, it is fixed to the hub 14 in this state.
In this state, the servo track information written on the disk 12 is written uniformly without displacing in the radial direction of the disk 12.

Next, the effect of the assembling accuracy of the centering device having the above structure on centering will be described with reference to FIG. As shown in FIG.
0a is mounted eccentrically by a distance d from a center line passing through the center of the hub 14, the value of d is
If the width is smaller than the width, the centering accuracy is not affected. Further, as shown in FIG. 4B, the error δ of the gap (both sides) when the rod 10a is inclined at the angle θ is expressed by the following equation.

Δ = (r ₂ −r ₁ ) (1−cos θ) where r ₂ indicates the inner radius of the disk 12 and r ₁ indicates the radius of the hub 14. Now, r ₂ −r ₁ = 100 μm,
If δ ≦ 1 μm, θ ≦ 8.1 °. As described above, since the angle θ is allowed up to 8.1 °, the allowable range of the inclination is large. Therefore, since the influence of rod assembly accuracy on centering is small, an effect is obtained that the centering device can be easily manufactured.

FIGS. 5A and 5B show a first embodiment of the centering device of the present invention using the above principle. FIG. 5A is a plan view and FIG. 5B is a side view. The illustrated centering device includes four actuator units 16a,
16b, 16c and 16d. The actuator units 16a to 16d are rods 10a to 10d, respectively.
d, linear actuators 18a to 18d, and actuator mounting plates 20a to 20d. The linear actuators 18a to 18d are respectively rods 10a to
10d is moved linearly. Each of the actuator mounting plates 20a to 20d is
a to 18d and supported on the base 24. The base 24 also supports the centering unit base plate 22.

FIG. 6 is a diagram showing the configuration of the actuator unit 16c. Actuator unit 16c
Includes the linear actuator 18c and the encoder 19c described above. The linear actuator 18c is
Having a rotating motor 18c ₁ and linear guide mechanism 18c _2. Actuator units having these components are known. Rotary motion of the rotary motor 18c ₁ is converted into linear motion by the linear guide mechanism 18c _2, rod 10
c is linearly moved. The encoder 19c detects the rotational position of the rotary motor 18c _1. Since the linear movement of the rotary motion and the rod 10c of the motor 18c ₁ are in linear relationship, the rotational position of the motor 18c ₁ will indicate the position of the rod 10c (coordinates on the x-axis). The other actuator units 10a, 10b and 10d have the same configuration as the actuator unit 10c.

FIG. 7 is a diagram showing an electric control system of the actuator device according to the first embodiment of the present invention. The illustrated electrical control system includes a host computer 26, a motor control board 28, a counter board 30, and a driver device 32. The host computer 26 composed of a personal computer or the like controls the motor control board 28 according to a program for realizing the operation described with reference to FIGS. Counter board 30 detects the encoder pulses from the encoder 19c shown in FIG. 6, the rotational position of the motor 18c _1, i.e. to detect the position of the rod 10c. The encoder pulse is also used by the host computer 26 to determine whether the rod 10c has contacted the disk 12 as described below.

The motor control board 28 drives the driver device 32 in response to a command from the host computer 26. The driver device 32 outputs a pulse signal to the rotation motor in the actuator units 16a to 16d to rotate the motor. For example, when the operation shown in FIG. 2A is executed, the host computer 26 causes the actuator unit 16a to move the rod 10a in the positive x-axis direction.
Is instructed to move the motor control board 28. The motor control board 28 sets an appropriate nearest target position, drives the driver device 32, and drives the rotation motor (the 18a
Drive ₁ ). Thereby, the rod 10a becomes x
Start moving in the positive direction of the axis. Thereafter, the motor control board 28 continuously updates the latest target position.

The host computer 26 includes a motor control board 28 which outputs the latest target position to the driver 32 and a rod 10 which the counter board 30 outputs.
The current position of a is monitored, and it is always determined whether or not the difference between the two is within a predetermined range. If it is less than the predetermined range, it indicates that the rod 10a is moving toward the nearest target position. By adjusting the degree of updating of the latest target position, the movement amount of the rod per unit time can be controlled. Therefore, for example, when the rod is moved for a long distance, the nearest target position is set so that the speed draws a so-called trapezoidal curve.

The determination as to whether the rod 10a has contacted the disk 12 will be described later. Further, as shown in FIG. 3, the target positions ((x1 + x2) / 2, (y1 + y2) /
When the rod is moved to 2), the host computer 26 sets this target position to the motor control board 2.
Give 8 Then, the motor control board 28 sets an appropriate latest target position, and performs a process of sequentially updating this.

The driver device 32 controls the actuator units 16a to 16d in accordance with the instructions from the motor control board 28, as described above. Also, it receives encoder pulses from each of the actuator units 16a to 16d and outputs them to the counter board 30.
The counter board 30 is provided for each actuator unit 16.
The encoder pulses are counted for each of a to 16d, and the positions of the rods 10a to 10d are detected.

The nearest target position may be coordinate data or data indicating the amount of movement.
For example, in FIG. 6, an amount corresponding to N pulses (N is an arbitrary integer) of the encoder 19c is set as the nearest target position, and whether or not the rod 10c of the actuator unit 16c has moved by N pulses is determined by the output of the encoder 19c. Is counted by the counter board 30 to make a judgment. When the movement for N pulses is detected, an amount corresponding to N pulses (or a value different from N) of the encoder 19c is set as the next nearest target position.

Here, a configuration for determining whether or not the rod 10c has come into contact with the disk 12 using the output pulse of the encoder 19c will be described. If the rod 10c is continuously driven after the rod 10c contacts the disk 12, the rod 10c may be driven in a state where the disk 12 contacts the hub 14 or in a state where the other rod 10a is engaged with the disk 12. 10c is driven, which is not preferable. Therefore, a configuration that can quickly detect that the rod 10c has stopped moving (stopped) is required. This detection is performed by comparing the difference between the latest target position and the actual movement position of the rod 10c, that is, the count value of the output of the encoder 19c (this is defined as a shift amount) with a predetermined threshold value.

FIG. 8 shows time and shift amount (expressed by the number of pulses).
FIG. 9 is a diagram showing the result of actually measuring the relationship with. While the movement of the rod is moving, the actual rod position with respect to the latest target position that is sequentially updated is equal to or less than a predetermined value. On the other hand, when the rod stops, the nearest target position is sequentially updated, so that the deviation amount increases sharply.
Therefore, for example, it is possible to determine that the rod has stopped when the threshold value is set to 100 pulses and the displacement exceeds 100 pulses. Then, the host computer 26 takes in the count value obtained at this time (for example, x ₁ , x ₂ , y ₁ , y ₂ ) from the counter board 30 and stores it.

By detecting the stop state of the rod as described above, it is possible to prevent the rod from forcibly pressing the disk 12. Whether or not the centering has been correctly performed in the above configuration can be verified by the method shown in FIG. The upper side of FIG. 9 shows a state in which the centering is completed, and the lower side shows a state in which the rod 10c is brought into contact with the disk 12 and the inner edge thereof is engaged with the hub 14. In advance, the center of the hub 14 and the four rods 10a to 10
Predetermined marks 34, 36, 38, and 40 are provided on the disk 12 on the line connecting d (only 10c is shown in FIG. 9). Mark 34 when in centering state
And the mark 34 with the inner edge of the disk 12 engaged with the hub 14
Is read optically. Then, the two images are compared by a known pattern matching technique. Thereby, the gap between the inner edge of the disk 12 in the centering state and the hub 14 can be measured. Similarly, the gaps are measured for the marks 36, 38, and 40, and the centering accuracy can be measured by comparing these gaps. The marks 34, 36, 3
8 and 40, for example, affix a seal on which a mark is displayed on the disk 12. Alternatively, a light-dark boundary generated at the inner edge of the disk 12 may be used.

In addition to the method shown in FIG. 9, there is a verification method described below. The centering positions of the rods 10a and 10b are measured in the same manner as the rods 10c and 10d. After the centering, the actual rod 10
The positions of a and 10b are compared with the centering positions of the rods 10a and 10b. If the comparison result is equal to or less than a predetermined value, it is determined that the centering has been performed normally. Judge that there is no. This verification is performed by the host computer 26.

Note that the four rods 10a to 10a
When the centering position is obtained for each of the rods 10d, the four rods 10a to 10d can be simultaneously operated in the centering operation shown in FIG. Next, a centering device according to a second embodiment of the present invention will be described. While the first embodiment has a single-layer configuration including four actuator units 16a to 16d, the second embodiment has a multilayer actuator unit so that a multilayer disk can be centered. . Actuator units 16a to 16d
If the same configuration is simply stacked as it is and multi-layered, the distance between the multi-layered actuator units becomes larger than the distance between the multi-layered disks, and all multi-layered disks cannot be centered. is there.

Therefore, in the second embodiment, FIG.
The actuator units 16a to 16a of the first embodiment shown in FIG.
As shown in FIG. 10B, the actuator units 46a to 46d constituting the second layer are arranged so as to be shifted by a fixed angle θ with respect to 16d. Thus, when viewed from the side, the first layer and the second layer partially overlap each other. Thereby, the interval between the rod of each actuator unit of the first layer and the rod of each actuator unit of the second layer can be matched with the interval of disks (not shown in FIG. 10) stacked on the two layers.

FIG. 11 is a view showing a centering device having a ten-layer structure in which actuator units are radially arranged. For example, the interval between discs having a 10-layer configuration is 4.8 m
m. As shown in FIG. 11A, four sets of first to fifth layers are arranged while shifting the actuator units by 18 degrees. In FIG. 11, all actuator units are indicated by reference numeral 16. In this case 6
The actuator units 16 in the first layer are stacked on the actuator units 16 in the first layer (having the same angle).
In FIG. 11A, 1 to 5 indicate the first to fifth layers, and (6) to (10) indicate the sixth to tenth layers stacked on the first to fifth layers, respectively. I have. The distance between the disks of the first layer and the sixth layer is 4.8 × (6-1) = 24 mm.
Is 24 mm. This interval is a value that can be actually realized.

FIG. 11C is a diagram in which the rod position viewed from the center of the hub is developed on a plane. As shown, 1
The rods of the actuator units 16 of the sixth and seventh layers, the second and seventh layers, the third and eighth layers, the fourth and ninth layers, the fifth and tenth layers are vertically overlapped. I have. The electric control system of the centering device having such a multilayer structure is the same as that shown in FIG. The centering of each layer can be performed simultaneously, can be performed simultaneously for each of a plurality of layers, or can be performed for each layer.

Next, the operation of writing servo track information on a disk using a centering device having a multilayered actuator unit as shown in FIG. 11 and mounting it on each magnetic disk device will be described with reference to FIGS. It will be described with reference to FIG. First, as shown in FIG. 12A, a plurality of disks 12 are mounted on the hub 14. Spacers 50 are interposed between the disks 12. Next, as shown in FIG. 12B, the disk unit of FIG. 12A is set on the shaft 13 of the centering device. Next, as shown in FIG. 12C, a centering operation is performed according to the above-described procedure. The centering operation can be performed simultaneously for each layer, can be performed simultaneously for a plurality of layers, or can be performed for each layer. In addition,
For simplicity, only some of the actuator units 16 are shown. When the centering operation is completed, the rod 10 of each actuator unit 16 is engaged with the outer peripheral edge of the corresponding disk 12, as shown in FIG. In this state, the ring 52 is screwed to the hub 14 and the disk 12 is fixed to the hub 14 in a centered state. Next, as shown in FIG. 12E, the actuator unit 16 is retracted,
The disk unit is removed from the shaft 13 of the centering device.

Next, as shown in FIG. 13A, the disk unit is fixed to the spindle 54 of the servo track information writing device. The servo track information writing device supports a drive unit 56 that drives the spindle 54, a head actuator 60 that generates servo track information and outputs the servo track information to a servo head supported by the actuator, and a drive unit 56 and the head actuator 60. And a base 58. The servo track information is written on the disk 12 by the servo head while rotating the spindle 54. Then, as shown in FIG. 13B, after removing the hub 14 from the spindle 54, the ring 52 is removed and the disk 12 is removed from the hub 14. And FIG.
As shown in (c), after the disk 12 on which the servo track information is written is mounted on each magnetic disk device, the disk 12 is centered on the spindle of the magnetic disk device by the centering device. Thereafter, the disk 12 is fixed to the spindle with screws.

In the above embodiment, the encoder 1
Although the position information of the rod has been acquired using 9c, a configuration in which the position information is optically acquired using a known optical device may be used. Although FIG. 7 shows a configuration for reducing the processing load on the host computer 26, a configuration in which the function of the control board 28 is performed by the host computer 26 may be used.

By the way, the centering device shown in FIG. 1 uses a centering method (operation) as shown in FIGS.
Is executed, it is necessary to consider the following points in addition to the configuration and operation described in the first and second embodiments. First, each rod 10a, 10b, 10
It is necessary to consider the moving distance of c and 10d. FIG.
As shown in (b), the tip of the rod 10c is
2d, and the difference between the tip position x2 of the rod 10c when the inner edge of the disk 12 contacts the hub 14 as shown in FIG. And the maximum travel distance (x direction) of 10c. At the same time, the difference between the positions y1 and y2, that is, the maximum moving distance (y direction) of the rods 10b and 10d is considered. For example, if each of the above differences is 0.1 mm, it is actually necessary to secure an operation range larger than that, and a moving distance of about 0.3 mm is usually required in consideration of settings and the like.

Second, each rod 10a, 10b, 10
It is necessary to consider the operation speeds of c and 10d. As shown in FIGS. 1, 2, and 3, when centering the disk 12, the step of operating each rod (for example, the operation of FIG. 1A) is actually performed 10 times or more. For example, in order to realize the centering of the disk 12 in 20 seconds, it is necessary to perform one rod operation in 2 seconds or less.

Third, it is necessary to consider the positioning accuracy of the disk 12. In order to accurately center the disk 12, it is assumed that the disk 12 is 1 μm in the description of FIG. 4B, but it is necessary to actually position the disk 12 at 0.5 μm or less. In the first embodiment and second embodiment, in order to satisfy the above three points, for example, as described in FIG. 6, linear guide mechanism a rotational motion of the rotary motor 18c ₁ 18
converted into a linear motion by c _2, the encoder 19c is measuring the rotational position of the rotary motor 18c _1. In particular,
A target rotation position P ₀ is commanded by a time function P ₀ (t), and a difference from the actual rotation position P (t) is obtained. _{That, Pe (t) = P 0} (t) -P (t) , and this Pe (t) is a predetermined threshold (this threshold is the condition for satisfying the points of the three) or more In this case, it is determined that the rod 10c has come into contact with the disk 12, and the position P (t) at that time is set to, for example, x1 or x1.
2 is stored. Then, based on x1, x2, y1, and y2 obtained as described above, FIG.
The centering shown in the figure is performed. Note that Pe (t) used to determine whether or not the disk 12 has come into contact with the disk 12
Is a value corresponding to the shift amount described above in FIG.

At this time, the actuator units 16a, 16b, 16c, 1
It is necessary to supply a relatively large current for moving each rod at high speed, that is, a current close to the rated current of the motor, to each rotary motor 6d (see FIGS. 5 and 6). However, when a current close to the rated current is supplied to the motor, the disc 12 may be plastically deformed in a time until it is determined whether or not each rod has contacted the disc 12. Measurement accuracy may deteriorate. Further, as shown in FIG. 3B, when the rods 10a and 10b are finally brought into contact with the disk 12, even if both are operated simultaneously, one of them actually comes into contact first. For example, if the rod 10a and the rod 10c hold the disk 12 first, the rod 10b cannot move due to the effect of the holding force, that is, the disk 12 cannot move to a predetermined position, and the accuracy of centering deteriorates. There is.

Thus, as a third embodiment, a centering device for solving the above problem will be described with reference to the drawings. FIG. 14 is a diagram for explaining the principle of the third embodiment. In the third embodiment, a position control mode control circuit 81 for controlling an operation mode (position control mode) for moving each rod at high speed is provided in a driver device 32 of the electric control system shown in FIG. A configuration including a current suppression mode control circuit 82 for controlling an operation mode (current suppression mode) when each rod is moved at a lower speed than the control mode, and a mode switcher 83 for switching between the modes according to an instruction from the host computer 26. And

The position control mode here is a normal position control operation similar to the first and second embodiments. Normally, in order to realize the high-speed operation of each rod, it is necessary to accelerate / decelerate each rotary motor in a short time. At the time of acceleration / deceleration, a current close to the rated current is supplied to each rotary motor as described above. Need to supply. Therefore, in the position control mode, the preparation operation and the post-processing operation of the operation (centering operation described later) in which each rod contacts the disk 12,
It is optimal for a rough operation such as an operation of moving each rod to the vicinity of the disk 12 and an operation of retracting each rod from the disk 12 after the centering operation is completed.

In the current suppression mode, the current supplied to each rotary motor is suppressed in response to a request from the host computer, and each rod is controlled to operate at a lower speed than in the position control mode. Therefore, the current suppression mode is optimal for a detailed operation such as an operation in which each rod contacts the disk 12 (a centering operation described later).

In this embodiment, a fine operation in which each rod comes into contact with the disk 12 is performed in the current suppression mode, and the operation of moving each rod to the vicinity of the disk 12 or the operation of moving each rod from the disk 12 after the centering operation is completed. Is performed in the position control mode. FIG. 15 shows an electric control system according to the third embodiment. still,
The configuration of the third embodiment is the same as the configuration of the first embodiment described with reference to FIG.
The configuration of the actuator unit shown in FIG.
Since the configuration is the same as that described above, the same reference numerals are given and the description is omitted.

The electric control system of the third embodiment has the same configuration as that of the first embodiment shown in FIG. 7, and includes a host computer 26, a motor control board 28, a counter board 30, and a position Switching between the control mode and the current suppression mode, a predetermined current is supplied to the actuator 16.
Driver device 9 for supplying a, 16b, 16c, 16d
1 is provided.

A host computer 26 such as a personal computer controls the motor control board 28 in accordance with a program (corresponding to FIGS. 16 and 17 described later) for performing a centering operation while switching between the position control mode and the current suppression mode. . In this embodiment,
The current suppression signal A is provided, and the control mode is divided according to the content of the current suppression signal A. For example, when the current suppression signal A is valid, the mode is set to the current suppression mode, and when the current suppression signal A is invalid, the mode is set to the position control mode.

The counter board 30 detects, for example, an encoder pulse from the encoder 19c, and
the rotational position P of c _1, i.e., detects the position of the rod 10c. Further, the encoder pulse is also used by the host computer 26 to determine whether the rod 10c has come into contact with the disk 12 as described in the first embodiment.

[0062] Motor control board 28 drives the driver unit 91 in response to the command value P _L from the host computer 26. The driver device 91 supplies a predetermined current to each rotation motor in the actuator units 16a to 16d. Further, the motor control board 28
Generates an appropriate nearest target position P ₀ of the rod to be moved and drives the driver device 91 to drive each rotary motor. Thereafter, the motor control board 28 continuously updates the nearest target position P ₀ .

The host computer 26 monitors the nearest target position P ₀ output from the motor control board 28 to the driver device 91 and the current position P of each rod output from the counter board 30, and the difference between them is within a predetermined range. Always determine if it is. The host computer 2
No. 6 performs this processing in both the position control mode and the current control mode. In the current control mode operation, the target position ((x1 + x2) / 2, (y1 + y2)
/ 2) to the case of moving the respective rod, the host computer 26 gives the target position on the motor control board 28 sets the motor control board 28 is appropriate immediate target position P _0, sequentially updated so Is performed.

The driver device 91 controls the actuator units 16a to 16d in accordance with the instruction from the motor control board 28, as described above. Also, it receives encoder pulses from each of the actuator units 16a to 16d and outputs them to the counter board 30.
The counter board 30 is provided for each actuator unit 16.
The encoder pulse is counted for each of a to 16d, and the position P of each of the rods 10a to 10d is detected.

FIG. 16 shows the operation of the host computer 26 when executing a program for performing the centering operation while switching between the position control mode and the current suppression mode. For example, when centering the disk 12 by the centering device of the third embodiment, the host computer 26 invalidates the current suppression signal A as a preparatory operation, and sets the operation mode of all the rods 10a, 10b, 10c, and 10d. Is set to the position control mode (S1). In this state, the driver device 81 supplies a current ie close to the rated current to each rotary motor in order to realize a high-speed operation of each rod. Thus, the host computer 26
Moves each rod to the vicinity of the disk 12 in the position control mode (high-speed operation) (S2).

Next, the host computer 26 validates the current suppression signal A and sets all the rods 10a, 10b, 1
The operation modes 0c and 10d are set to the current suppression mode (S3), and the centering operation (in FIG. 16) is started.
First, the host computer 26 determines the centering position ((x1 + x2) / 2, (y1 + y) by the procedure shown in FIG.
2) / 2) is measured (S4).

The operation of the driver device 91 in the position control mode and the current suppression mode will be described with reference to FIG. The description of FIG. 18 focuses on the current suppression mode, which is a point of the present invention. The driver device 91 includes:
When each mode is set by the host computer 26,
All parameters such as the counter current value receiving unit 92 and the command value receiving unit 93 are reset (S31 in FIG. 18). Here, when the motor control board 28 receives the final target position P _L which is a command value from the host computer 26, the motor control board 28 outputs the nearest target position P ₀ at regular intervals, for example, at 1 mS intervals. .
When the command value receiving unit 93 receives the nearest target position P ₀ ,
The calculation unit 95 reads the nearest target position P ₀ and the current position P (corresponding to the actual rotation position P) received by the counter current value reception unit 92 (S32, S33), and calculates the position deviation Pe (S32). S34), the control circuit 94 is notified.
The control circuit 94 calculates a current value ie to be commanded to the drive circuit 96 based on the position deviation Pe (S3).
5). After the calculation, the control circuit 94 checks whether the currently set operation mode is the position control mode or the current suppression mode (S36). If current suppression mode (S36, YES), reads the maximum current i ₀ of the current suppressing mode that has been set in advance (S37). Here, the control circuit 94 operates the drive circuit 9 calculated in step S35.
6 is compared with the maximum current i ₀ , and if ABS (i ₀ ) <ABS (ie) (S3
8, YES), the maximum current i ₀ is set as the command current i to the drive circuit 96 (S39), and ABS (i ₀ )> ABS (i)
e) (S38, NO), the maximum current ie is set as the command current i (S40), and a command is issued to the driver circuit 96 (S40).
41). Therefore, in the current suppression mode, no current greater than i ₀ is applied to each motor. Step S3
In the case of NO at 6, since the camera is operating in the position control mode,
The current during the high-speed operation, that is, the current ie to be instructed to the drive circuit 96 calculated in step S35 is directly used as the command current i to the drive circuit 96 (S40). The ABS indicates an absolute value.

By repeating the operation of the driver device 91, the host computer 26 determines the centering position ((x1 + x2) / 2,
(Y1 + y2) / 2) is measured (S4). In the current suppression mode operation, if the current is suppressed below the current required for acceleration, sufficient acceleration cannot be performed in each lot, and the position deviation Pe becomes apparently large. It may be detected. Therefore, in order to avoid such a problem, it is desirable to set the maximum speed and the maximum acceleration to be sufficiently small in the current suppression mode. For example, if the maximum speed in the current suppression mode operation is set to 1/5 of the maximum speed in the position control mode operation, the current must be increased to reach the maximum speed in the same acceleration time as in the position control mode operation. The maximum acceleration during the suppression mode operation may be set to 1/5 of the maximum acceleration during the position control mode operation. In this way, if the maximum speed is set low in advance, the current during acceleration can be set small. Therefore, even at the time of contact, the current supplied to each motor can be reduced, and the force applied to the disk 12 can be greatly reduced. In addition, the deformation of the disk 12 that occurs at the time of abutment can be reduced by greatly reducing the force applied to the disk 12.
The effect can be reduced.

After measuring the centering position in step S4, the host computer 26 invalidates the current suppression signal A, sets the operation modes of all the rods to the position control mode (S5), and temporarily resets all the rods. The disk is retracted to a position near the original disk 12 (S6). Next, the host computer 26 moves the rods 10c and 10d to the centering position at a high speed according to the procedure shown in FIG. 18 described above (S7). Next, rod 10a and rod 1
0b is set to the current control mode (S8), and the rod 1
0a is brought into contact with the disk 12 (S9), and the rod 10c
And the disk 12 is held by the rod 10a. here,
The host computer 26 once retreats the rod 10a to a predetermined position (as close as possible) (S10), then brings the rod 10b into contact with the disk 12 (S11), and holds the disk 12 with the rod 10c and the rod 10a. (See the operation of FIG. 3). In step S10, the rod 1
The distance for retracting Oa is determined by, for example, using the fact that the pushing force of the rod 10a against the disk 12 and the amount of deformation of the disk 12 are in a proportional relationship, and the distance at which the holding force between the rod 10c and the rod 10a is weakened. For example, 1kgf / μ
When the proportional relationship of m is established, the holding force at the time of abutment is reduced to 0.5 μm by retracting the rod 10a by 0.5 μm.
It can be reduced by 5 μmf. Further, in order to perform centering with higher accuracy, it is desirable to correct the centering position in consideration of the deformation amount. in this case,
The gap between the disk 12 and the shaft is measured by image processing or the like, and is corrected based on the information.

In this state, the disk 12 is fixed to the hub 14 (S12), and the host computer 26 sets the operation mode of all the rods to the position control mode (S1).
3), all the rods are largely retracted (S14). Thereafter, the hub 14 for which centering has been completed is removed from the shaft of this embodiment (S15), and the centering operation while switching between the position control mode and the current suppression mode is completed.

The centering operation shown in FIG. 16 can be replaced with, for example, the centering operation shown in FIG. Note that, in FIG. 17, the same operations as those in FIG. 16 are denoted by the same reference numerals, and description thereof will be omitted. After the operation of steps S3 to S7 is completed, in FIG. 17, the host computer 26 sets only the rods 10a and 10b to the current control mode (S21).
At this time, the current for driving the motors 18a and 18b is set so that the suppression current of the rod 10a <the suppression current of the rod 10b. In this state, the host computer 26 brings the rod 10a into contact with the disk 12 (S22), and holds the disk 12 with the rod 10c and the rod 10a. Subsequently, the host computer 26
The rod 10b is brought into contact with the disk 12 (S23), and the disk 12 is held by all the rods (see the operation in FIG. 3). In this case, since the moving force of the rod 10b is larger than the holding force of the rods 10c and 10a, the disc 12 can be moved, and the accuracy of centering may be deteriorated as in the problem described above. Absent.

In the third embodiment, when the centering position is obtained for each of the four rods 10a to 10d as described above, the four rods 10a to 10d are simultaneously moved as shown in FIG. Can work. In the third embodiment, when operating in the current suppression mode, the control circuit 94 notifies the driver circuit 96 of the command current i. However, the command from the control circuit 94 is not limited to this. The driver circuit 96 may be controlled by voltage.

As described above, according to the third embodiment, the plastic deformation of the disk 12 is suppressed, and the position measurement accuracy at the time of contact does not deteriorate. The rod 10a and the rod 1
Even if 0c holds the disk 12 first, the rod 10b does not become unable to move due to the effect of the holding force, and the accuracy of centering is improved. FIG.
Indicates that the host computer 26 directly receives the current position P from the counter current value receiving unit 92,
0 shows a configuration in which the host computer 26 performs other functions. The operation in this case is shown in FIGS.
7 and FIG. 18, and a description thereof will be omitted for simplicity.

[0074]

As described above, according to the present invention,
It is possible to provide a centering apparatus and a centering method capable of centering a disk with respect to an axis such as a shaft while maintaining a constant gap.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a centering device according to the present invention;

FIG. 2 is a diagram illustrating an operation of detecting a centering position according to the principle of the present invention.

FIG. 3 is a diagram showing an operation of centering a disk at a detected centering position.

FIG. 4 is a diagram for explaining the effect of assembling accuracy of the centering device on centering.

FIG. 5 is a diagram showing a first embodiment of the centering device of the present invention.

6 is a diagram showing a configuration of the actuator unit shown in FIG.

FIG. 7 is a diagram showing an electric control system of the actuator device according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a result of actually measuring a relationship between time and a shift amount (expressed by the number of pulses) regarding detection of an operating state of a rod.

FIG. 9 is a diagram illustrating an example of a configuration for verifying whether centering has been correctly performed.

FIG. 10 is a diagram showing a centering device according to a second embodiment of the present invention.

FIG. 11 is a view showing a centering device having a ten-layer structure in which actuator units are radially arranged.

FIG. 12 is a diagram showing an operation of writing servo track information to a disk using a centering device having a multilayered actuator unit.

FIG. 13 is a diagram showing an operation of mounting a disk on each magnetic disk device using a centering device having a multilayered actuator unit.

FIG. 14 is a diagram for explaining a third embodiment.

FIG. 15 is a diagram showing an electric control system of an actuator device according to a third embodiment of the present invention.

FIG. 16 shows a method of performing a centering operation while switching between a position control mode and a current suppression mode.

FIG. 17 shows a method of performing a centering operation while switching between a position control mode and a current suppression mode.

FIG. 18 is a diagram illustrating an operation flowchart of the driver device.

FIG. 19 is a diagram for explaining a third embodiment.

[Explanation of symbols]

 10a-10d Rod 12 Disc 14 Hub 16a-16d Actuator unit 18a-18d Actuator 19c Encoder 20a-20d Actuator mounting plate 22 Centering unit base plate 22 24 Base 26 Host computer 28 Motor control board 30 Counter board 32 Driver device 81 Position control Mode circuit 82 Current suppression mode circuit 83 Mode switcher 91 Driver device 92 Counter current value receiving unit 93 Command value receiving unit 94 Control circuit 95 Operation unit 96 Drive circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hitoshi Komoriya 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hiroshi Nakamura 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 Fujitsu Co., Ltd. (72) Inventor Takao Hirahara 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Fujitsu Co., Ltd.

Claims (22)

[Claims] 1. A centering device for centering a disk with respect to an axis, wherein at least a plurality of sets each including two actuator units each having a member capable of moving straight and abutting on the disk at a position facing each other with respect to the disk. A centering device characterized by the following. 2. The centering device according to claim 1, wherein the plurality of sets of actuator units are respectively located on straight lines passing through the center of an axis and extending in different directions. 3. The control device according to claim 1, further comprising: a mode switching unit that can select a control mode of the actuator unit according to a centering situation; and a control unit that controls the actuator unit in a selected predetermined control mode. The centering device according to claim 1. 4. The selected control mode is one of a position control mode for performing high-speed position movement and an output suppression mode for performing low-speed position movement by suppressing speed and acceleration. 4. The centering device according to claim 3, wherein the mode is set to the following mode. 5. The centering device has a first set and a second set, and in each of the first set and the second set, two actuator units respectively form the first and second sets constituting the member.
In the first set, the first rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft, and the second rod is in contact with the outer periphery of the disk. The position of the second rod is x1, and the position of the second rod in the state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is x2.
In the second set, the second rod in a state where the first rod contacts the disk and the inner periphery of the disk engages with the shaft and the second rod contacts the outer periphery of the disk The position is y1, and the position of the second rod in a state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is y2.
In this case, the disc is (x1 + x2) / 2 by each set of rods,
5. The centering device according to claim 1, wherein the centering is performed at a centering position of (y1 + y2) / 2. 6. The centering apparatus according to claim 5, wherein a process of contacting each set of rods with a disc and a process of centering at the centering position are performed in an output suppression mode. 7. The actuator unit according to claim 1, wherein each of the actuator units includes a motor that can be controlled by a current supply amount. When the output suppression mode is operating, the current supplied to the motor is suppressed, so that the moving speed of each set of rods is adjusted. 7. The centering device according to claim 5, wherein the acceleration and the acceleration are adjusted. 8. In the processing of centering a disk at the centering position by each set of rods, a current supplied to a set that performs the preceding centering is made smaller than a current supplied to a set that performs the subsequent centering. The centering device according to any one of claims 5 to 7, wherein: 9. A process of centering a disk at the centering position by the rods of each group, wherein a current supplied to a group for performing centering in advance and a group for performing centering in subsequent steps are fixed, and the centering of the preceding centering is terminated. The centering device according to any one of claims 5 to 7, wherein the rod is retracted from the abutting disk to perform subsequent centering. 10. The method according to claim 1, further comprising: determining that the movement of the member has stopped when a difference between the movement amount input to the actuator unit and the actual movement amount of the member is larger than an allowable deviation amount. The centering device according to any one of claims 1 to 9, further comprising: 11. The centering device according to claim 10, further comprising a second unit that outputs position information of the member when it is determined that the movement of the member has stopped. 12. The apparatus according to claim 1, wherein the plurality of sets of actuator units are multilayered in an axial direction.
12. The centering device according to any one of claims 11 to 11. 13. The first set of first rods and second rods.
10. A means for determining a centering position for each of the first rods of the set and verifying whether centering has been correctly performed based on the centering positions for all the rods. The centering device according to the item. 14. The centering device according to claim 1, wherein the disk is a recording medium. 15. A centering method for centering a disk with respect to an axis, wherein at least a plurality of sets of two actuator units each having a member capable of moving straight and contacting the disk at a position facing each other with respect to the disk are used. A centering method characterized by performing centering. 16. The method according to claim 15, further comprising: selecting a control mode of the actuator unit according to a centering situation; and controlling the actuator unit in the selected predetermined control mode. Centering method. 17. The selected control mode is one of a position control mode for performing high-speed position movement and an output suppression mode for performing low-speed position movement by suppressing speed and acceleration. 17. The centering method according to claim 16, wherein the mode is set to: 18. It has a first and a second set of two actuator units, and each of the first and the second sets has a first and a second rod constituting the member, respectively. In the first set, the position of the second rod in the state where the first rod contacts the disk and the inner periphery of the disk engages with the shaft and the second rod contacts the outer periphery of the disk is determined. x1, and the position of the second rod in a state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is x2.
In the second set, the second rod in a state where the first rod contacts the disk and the inner periphery of the disk engages with the shaft and the second rod contacts the outer periphery of the disk The position is y1, and the position of the second rod in a state where the second rod is in contact with the disk and the inner periphery of the disk is engaged with the shaft is y2.
In this case, the disc is (x1 + x2) / 2 by each set of rods,
18. The centering method according to claim 15, wherein centering is performed at a centering position of (y1 + y2) / 2. 19. The centering method according to claim 18, wherein a process in which each set of rods abuts a disk and a process in which the rods are centered at the centering position are executed in an output suppression mode. 20. The actuator unit, wherein each of the actuator units has a motor that can be controlled by a current supply amount, and in an output suppression mode operation, the current supplied to the motor is suppressed to thereby move the rods in each set. 20. The centering method according to claim 18, wherein the acceleration and the acceleration are adjusted. 21. In the process of centering a disk at the centering position by each set of rods, a current supplied to a set which performs centering in advance is made smaller than a current supplied to a set which performs centering subsequently. 21. The centering method according to claim 18, wherein: 22. In the processing of centering a disk at the centering position by the rods of each set, a current supplied to a set for performing centering in advance and a set for performing subsequent centering are fixed, and the end of the preceding centering is ended. The centering method according to any one of claims 18 to 20, wherein the rod is retracted from the abutting disc and subsequent centering is performed.