JPS6249664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a swing actuator that can perform high-speed positioning operations stably and safely.

[Conventional technology]

In magnetic disk drives, mechanisms for positioning a magnetic head at a predetermined track position include a linear actuator and a swing actuator. Conventionally used linear positioners have a large number of parts that make up the guide system, have complex mechanisms, and require a long operating range.
There were limits to miniaturization. On the other hand, the swing actuator has a simple mechanism and is therefore advantageous in terms of size and weight reduction.

FIG. 1 shows an example of a swing actuator. In this figure, 1 is a magnetic disk, 2 is a magnetic head,
This magnetic head 2 is fixed to an arm 3, and is driven around a swing shaft 5 by a linear motor composed of a coil 4 and a magnetic circuit (not shown). Normally, a plurality of magnetic disks 1 and arms 3 are stacked, and positional information is written in advance on one disk surface (servo disk), and this positional information is read by a dedicated head (servo head), and based on this positional information. , by feedback control that controls the current flowing through the coil 4,
It is positioned at a predetermined track position.

[Problem that the invention seeks to solve]

In a feedback control system, if there is mechanical resonance of a certain amplitude level or higher in the mechanical system, the control system will oscillate and stable positioning operations will not be possible. In a linear actuator, the vibration mode is tension/compression mode (longitudinal vibration), whereas in a swing actuator, a lateral force acts on the swing shaft or movable body, so vibration is in the bending mode (lateral vibration). Easy to appear. In structures, transverse vibrations appear at lower frequencies than longitudinal vibrations, so vibration suppression has been a major issue in the mechanical configuration of swing actuators.

The present invention eliminates the above-mentioned drawbacks and provides a swing actuator that is capable of highly accurate and stable head positioning control by increasing the rigidity of the actuator mechanism and raising the mechanical resonance point.

[Means for solving problems]

A swinging body is constructed by stacking one or more swingable arms equipped with magnetic heads that write data on a magnetic disk and read information from the magnetic disk, and the swinging axis of this swinging body is the center of rotation. In the swing actuator that positions the magnetic head on a predetermined track by a swing motion, a linear motor that swings the swing body is provided, and the housing of the linear motor is connected to the center axis of the swing shaft and the linear motor. The upper end of the housing and the upper end of the swing shaft are configured symmetrically with respect to a plane passing through the center of the motor and the center of the linear motor. They are connected via a connecting plate.

[Effect]

The upper end of the highly rigid shell-shaped housing of the linear motor and the upper end of the swing shaft are connected via a connecting plate, resulting in a structure in which the swing shaft is supported at both ends, reducing the rigidity of the swing shaft. It can be significantly improved.
Therefore, the resonant frequency of transverse vibration can be increased and vibration can be suppressed.

In addition, the upper end of the swing shaft is now fixed with a connecting plate that is symmetrical in the swing direction of the arm, so the structure for fixing the swing shaft is a pseudo-symmetrical structure in the axial direction of the swing shaft. At the same time, the structure becomes symmetrical with respect to the swinging direction of the arm, and the coupled effect of vibrations in the swinging direction and vertical vibrations can be reduced.

〔Example〕

FIGS. 2 and 3 are a partially cutaway side view and top view showing an embodiment of the present invention.
In these figures, 6a is a data arm having a data head installed at its tip A, and 6b is a servo arm having a servo head installed at its tip A, and the entire arm 6 is shown. 7 is a swing shaft, 8a and 8b are bearings arranged at the upper and lower parts of the swing shaft 7, and 9 is a rotatable sleeve fixed to the outer ring of the bearings 8a and 8b. The servo arm 6b is located approximately at the center in the stacking direction, and has a lever 10 integrally formed on the opposite side of the tip A with respect to the swing center O, and fixes a bobbin 12 around which a drive coil 11 is wound around the lever 10. do. The arm 6 is fitted into the sleeve 9 and stacked, and is integrated by a connecting pin 13 and a connecting screw 14, and the arm 6, sleeve 9, drive coil 11, and bobbin 12 constitute a swinging body 15. Denoted at 16a and 16b are two permanent magnets arranged one above the other, and the drive coil 11 is movably arranged within the opposing interval between the two permanent magnets. The permanent magnets 16a, 16b and the drive coil 11 constitute a linear motor 17. And the swing axis 7
The linear motor 17 is fixed to the base 18, and the upper end of the housing 23 of the linear motor 17 and the upper end of the swing shaft 7 are firmly connected via a connecting plate 19. Reference numeral 20 denotes a pawl, which is integral with the lever 10 and arranged approximately symmetrically with respect to the center line P of the arm 6;
Reference numeral 1 denotes a stopper, which is preferably made of a highly elastic material in order to buffer the impact force. Stoppa 2
1 is attached to a support leg 22 whose one end is fixed to the base 18, and is arranged so as to restrict the swingable range by engaging with the pawl 20.

Since the housing 23 can be configured in a shell shape, it can have significantly higher rigidity than the swing shaft 7. Therefore, by connecting the swing shaft 7 to the housing 23 via the connecting plate 19, the rigidity of the swing shaft 7 can be greatly increased. FIG. 4 shows a concrete implementation effect example. The vertical axis in FIG. 4 indicates the excitation force f when the coil 11 is excited by applying a sinusoidal current
It is the ratio (inertance) of the response acceleration α at the tip A of the servo arm to the servo arm, and the horizontal axis is the frequency. 4a is the case when the connecting plate 19 is not used, and FIG. 4b is the case when the connecting plate 19 is used.
It is. The resonance point of the first-order mode (lowest frequency) is 1 kHz in a of Fig. 4, while it is 1.8 kHz in b of Fig. 4, and the effect of increasing rigidity by the connecting plate 19 is remarkable. I understand that. FIG. 5 is an example of actual measurements of vibration modes at the resonance points of the respective primary modes shown in FIG. In FIG. 5A, the swing shaft is tilted due to vibration, but in FIG. 5B, it can be seen that the magnitude of the tilt is becoming smaller.

Further, according to the present invention, the swing shaft 7 is supported in a pseudo symmetrical structure at both ends in the axial direction, and is fixed in the swing direction of the arm by the left-right symmetrical housing 23 and the connecting plate 19. for,
The following advantages arise. In other words, even if an accident occurs in which the oscillator 15 runs out of control due to a malfunction of the feedback control system and the pawl 20 violently collides with the stopper 21, the coupled effect of the vibration in the oscillation direction and the vibration in the vertical direction is maintained. Because it is small, it is coupled to the vibration in the rocking direction excited by the collision,
No vertical vibration occurs. Therefore, the relative positional relationship between the magnetic head and the magnetic disk does not shift, and the safety of high-speed relative movement between the magnetic head and the magnetic disk is enhanced.

The connecting plate 19 of the present invention can be easily assembled by simply tightening screws from above after assembling the swing shaft 7 and the housing 23, and is suitable for mass production.

[Effects of the Invention] As explained in detail above, according to the present invention, the rigidity of the actuator mechanism can be greatly improved, and the vertical vibration that occurs in conjunction with the vibration in the swinging direction of the arm can be suppressed. This greatly improves the stability of the positioning control system, making it possible to achieve highly accurate head positioning. Therefore, if the swing actuator of the present invention is used, the stability and safety of the positioning operation can be increased simply, and the positioning operation can be made with higher precision and faster. It is possible to achieve high performance.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing the configuration of a swing actuator, Fig. 2 is a partially sectional side view showing an embodiment of the present invention, and Fig. 3 is a partially sectional view of Fig. 2. The plan view and FIG. 4 are examples of practical effects of the present invention, and FIG. 5 is a detailed explanatory diagram of the practical effects of FIG. 4. In the figure, 1 is a magnetic disk, 2 is a magnetic head, and 6
a is a data arm, 6b is a servo arm, 7 is a swing shaft, 8a, 8b are bearings, 10 is a lever, 11 is a drive coil, 12 is a bobbin, 15 is a swing body, 16
a, 16b are permanent magnets, 17 is a linear motor, 1
8 is a base, 19 is a connecting plate, 20 is a pawl, and 21 is a stopper.

Claims (1)

[Claims] 1 A rocking body is constructed by stacking one or more swingable arms equipped with magnetic heads that write data on a magnetic disk and read information from the magnetic disk, and the rocking axis of this rocking body is rotated. In a swing actuator that positions the magnetic head on a predetermined track by a swing motion about the center, a linear motor that swings the swing body is provided, and the housing of the linear motor is connected to the center axis of the swing shaft and the The upper end of the housing and the upper end of the swing shaft are configured symmetrically with respect to a plane passing through the center axis of the swing shaft and the center of the linear motor. A swing actuator characterized in that the actuator is connected via a shaped connecting plate.