JPS6228505B2 - - Google Patents

Description

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

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), 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.

If the position information is disturbed by a defect in the position information on the magnetic disk 1 or by disturbances caused by vibrations induced by the rocking motion or disk rotational motion, the rocking body will run out of control due to malfunction of the feedback control system. A high-speed collision may occur with the stopper that restricts the swing angle range. In a high-speed positioner, the collision speed reaches several m/sec, and at this time, a force hundreds of times the gravitational acceleration is applied to the magnetic head 2, so the magnetic head 2 is struck against the surface of the magnetic disk 1, causing the magnetic head 2 to collide with the surface of the magnetic disk 1. and magnetic disk 1
was damaged and became unusable. Furthermore, in order to improve safety, the positioning speed must be lowered, which has been an obstacle to increasing the speed of the actuator.

In order to eliminate the above-mentioned drawbacks, this invention prevents runaway collisions and high-speed rocking motions in the vertical direction of the disk surface of the magnetic head by appropriately arranging the point of application of the driving force and the position of the stopper. The purpose is to provide a high-speed rocking actuator with excellent safety. This invention will be explained below.

FIGS. 2 and 3 are a partially cutaway side view and top view showing one 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 a bobbin 12 around which a driving coil 11 is wound around the lever 10. Fix it. The arm 6 is inserted 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, driving coil 11, and bobbin 12 constitute a swinging body 15. 16a, 16b are 2 above and below
The driving coil 11 is movably arranged within the opposing interval between the permanent magnets arranged one by one. A linear motor 17 is constituted by the permanent magnets 16a, 16b and the drive coil 11. The swing shaft 7 and the linear motor 17 are fixed to a base 18, and the upper end of the housing of the linear motor 17 and the upper end of the swing shaft 7 are firmly connected via a connecting plate 19. 20 is an arm 6 integrated with the lever 10.
The pawls 21 are stoppers arranged approximately symmetrically with respect to the center line P of the holder, and are preferably made of a highly elastic material in order to buffer the impact force. One end of the stopper 21 is attached to a support leg 22 fixed to the base 18, and is arranged so as to restrict the swingable range by engaging with the pawl 20.

Next, the effect will be explained. Positioning of the magnetic head is performed by controlling the current flowing through the drive coil 11 using the position information read by the servo head, but if the feedback control system malfunctions, the oscillator will run out of control and the pawl 20 will collide with the stopper 21. I will do it. As described above, the swing actuator of the present invention has high symmetry in the vertical direction, so it has the following vibrational advantages. That is, in the event of a runaway collision, the oscillator 15 will stop at the stopper 21.
However, since the stopper 21 is located near the vertical center of inertia (center of gravity) of the rocking body 15, the bending moment acting on the rocking body 15 is small, and almost no vertical displacement of the arm 6 occurs. do not have. In addition, since the oscillator 15 has high symmetry in the vertical direction, the coupling effect of the vibration in the oscillating direction and the vibration in the vertical direction is small, and therefore, the coupling effect between the vibration in the oscillating direction and the vibration in the oscillating direction induced by a collision is small. Therefore, vibrations in the vertical direction are less likely to occur. Furthermore, since the stopper 21 is located away from the magnetic head mounting position,
The elastic vibration waves generated at the collision point are sufficiently attenuated by the time they reach the mounting position of the magnetic head, and less elastic vibration is transmitted to the magnetic head.

The pawl 20 can be easily formed integrally with the lever 10 for attaching the bobbin 12, and sufficient strength can be easily obtained. Further, since the arm 6 having the claw 20 can be constructed by simply stacking the arm 6 on the sleeve 9 without requiring any special parts, assembly is easy.

In the event of a runaway collision, force also acts on the swing shaft 7 via the bearings 8a, 8b. The connecting plate 19 is a member for increasing the rigidity of the swing shaft 7 and suppressing deformation and vibration of the swing shaft 7 by connecting the upper end of the swing shaft 7 and the upper end of the linear motor 17. This further enhances the structural symmetry of the entire actuator,
The above advantages become even more remarkable.

As described in detail above, according to the present invention, it is possible to configure a rocking body with small vertical displacement and vibration induced by a runaway collision of the actuator, so that the magnetic head This makes it possible to prevent damage caused by contact between the magnetic disk and the magnetic disk. Further, since the symmetry of the entire structure can be increased, less vibration is induced in the positioning operation, and the stability of the positioning operation can be improved. Further, in this invention, the housing of the linear motor and the upper end of the swing shaft are connected by a connecting plate, so the overall rigidity is increased and the resonance point is raised, so that more stable operation can be obtained. Further, in this invention, the housing of the linear motor and the upper end of the swing shaft are connected by a connecting plate, so the overall rigidity is increased and the resonance point is raised, so that more stable operation can be obtained. Therefore, by using the swing actuator of the present invention, the stability and stability of the positioning operation can be increased simply, and the speed of the positioning operation can be correspondingly increased. can be achieved.

[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. FIG. In the figure, 1 is a magnetic disk, 2 is a magnetic head, and 6 is a magnetic disk.
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. A swing actuator for positioning the magnetic head on a predetermined track by swinging motion about a center, a lever for mounting a driving coil on the opposite side of the swing shaft from the mounting position of the magnetic head; A pawl integrally formed with the arm is provided on this lever, and the arm on which this pawl is formed is placed in a vertically symmetrical position with respect to the rocking body, and engages with the pawl on the fixed side so that the rocking body can swing. A swing actuator characterized by being provided with a stopper that defines a range.