JPS6093683A - Actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a head positioning mechanism (hereinafter referred to as an actuator) for a magnetic disk drive, and particularly to a guide mechanism for a carriage in which an actuator is installed.

[Background of the invention]

In a magnetic disk device, positioning of a magnetic head to a target track on a magnetic disk is performed by driving a voice coil motor based on a servo signal written on the magnetic disk.

A conventional actuator will be explained with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing a conventional actuator,
FIG. 2 is a sectional view of FIG. 1 viewed from the direction of arrow X.

The movable parts of the actuator include a magnetic head 1 that reads and writes information, a head arm 8 that supports the magnetic head 1, and a head arm 8 that supports the magnetic head 1.
A head arm mounting part 9 to which the head arm 8 is attached, a head arm mounting part 9, and the coil 2 of the voice coil motor.
The coil 2 is comprised of a carriage 3 that connects the coils 2 and 2. This movable part is moved by electromagnetic force obtained by passing a current through the coil 2 in the magnetic field generated by the permanent magnet 6 of the voice coil motor.

The moving direction of the movable part is determined by guiding the carriage 3. That is, the carriage 3 has a prismatic section 1
A guide rail 7 is provided on the slope of the prismatic portion lO, and a bearing 4 attached to the gear ridge guide 5 rotates on the guide rail 7, so that the carriage 3 moves in the direction of arrow A. Guide it to move only in the theta direction shown. Note that the protrusion 11' of the fin-like support 11 is formed as a stopper when the carriage 3 runs out of control due to a seek error or the like.

However, such a bearing 4, carriage guide 5
, guide rail 7 is mounted in a narrow space inside the coil 2, so the carriage 3 and carriage guide 5 are small and have a complicated shape.

Due to high density recording in recent magnetic disk drives, Iμr
Head positioning accuracy of n or less is required, and to achieve this, the natural frequency of the carriage 3 in the theta direction must be 5~
7 K l (v) degree is required, and the carriage guide 5 is also required to have a certain rigidity to prevent disturbance. It is necessary to perform a vibration analysis, but if the shape is complex, this analysis will be a difficult task, and since the carriage guide 5 is mounted in a narrow space, increasing its rigidity will also be a difficult task.

As described above, the conventional actuator has the drawback that B i14 requires time and effort, and once a problem occurs, it takes a huge amount of time to solve the problem. Furthermore, the structure of the carriage itself is complicated and difficult to manufacture.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above,
An object of the present invention is to provide an actuator that has a simple structure, is easy to manufacture, and allows high-speed, high-precision access.

[Summary of the invention]

To achieve the above object, the present invention provides an actuator for a magnetic disk drive that includes a magnetic head, a carriage on which the magnetic head is mounted, and a voice coil motor that drives the carriage. A cylindrical carriage having the same diameter as the coil, the cylindrical carriage and the coil are connected so that their diameters match, and a guide rail and a guide mechanism for supporting and guiding the guide rail are provided on the outside of the carriage. It is distinctive in that it was established.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.

FIG. 153 is a perspective view showing the movable part of the actuator according to the first embodiment of the present invention.

The hem 1 to the arm 8 are attached to the navel arm receptacle 1 part 9, and the head arm receptacle part 9 and the carriage 12 are joined. The carriage 12 has a cylindrical shape with a narrow core having the same diameter as the coil 2, and is joined to the coil 2 with the same axis. In this way, the carriage]2 according to this embodiment is
Since it is cylindrical and does not have a prismatic column IO with a large mass as in the conventional example shown in FIG. 2, it is lightweight and allows high-speed and high-precision access.

Four guide rails 13 are provided on the outside of the carriage 12 and the coil 2, respectively. By rotating the bearing 4 on this guide rail 13, the carriage 12 can move linearly only in the theta direction shown by arrow A.

Reference numeral 14 denotes a stopper mounted on the carriage 12, which is engaged with a stopper receiving portion (not shown) provided on a carriage guy 1-]5, which will be explained next, to control the amount of movement of the carriage 12. regulate. 6 is a permanent magnet as a component of the voice coil motor.

FIG. 4 is a cross-sectional view of an actuator showing the first embodiment of the present invention, with a carriage guy 15 for guiding the movable part shown in FIG. 3 added thereto. Figure 5 (,) is a cross-sectional view taken along line B-B in Figure 4, and Figure 5 (b) is B-B.
A diagram for explaining the acting force of each hair ring in the B-line cross section. It is a figure for explaining the acting force of a bearing.

The bearing 4 shown in FIG. 3 is supported by a carriage guide 15, as is clear from FIGS. 4 to 6. There are a total of 18 bearings 4, of which 5 are rotatably attached directly to the carriage guide 15, and the other 3 are attached to the bearing support 16 in order to eliminate "backlash" in the carriage 12. rotatably supported,
The bearing support body 16 is configured to be preloaded by a spring 17 to suppress the coil 2 and the carriage I2.

By the way, as shown in FIG. 5(b), in the cross section taken along line B-B, four guide rails 13 and bearings 4
, the acting force of the bearing 4 is at the center axis 0 of the carriage 12.
It is configured so that it can be used without any trouble.

The two bearings tilting to the right rotate the carriage 12 to the right, and the two bearings tilting to the left rotate the carriage 12 counterclockwise. It's out of place. By making the rotational forces in both the left and right directions equal, rotation of the carriage 12 can be prevented.

On the other hand, as shown in FIG. 6(b), the guide rail 13 provided on the coil 2 is configured so that the acting force of the bearing supporting it is all directed toward the center of the coil 2. . Therefore, the slight rotation θ of coil 2
The deviation in the X direction (theta direction) can be suppressed to a minimum.

The shape of the carriage guide 15 is such that its cross section is that of the coil 2,
The coil 2 and the carriage 12 are placed in a hole (cylindrical hole) formed by the inner circumference of the carriage guide 15. It has been inserted. In this state inserted into the cylindrical hole, a guide groove 18 is formed at a position corresponding to the guide rail 13 provided on the coil 2 and the carriage 12.
The above-mentioned bearing 4 is provided.

In addition, the bearing 4, guide rail 13, guide groove 18
The reason why four sets of guide mechanisms for guiding the movable part, each consisting of a movable part guide mechanism, are provided on both the carriage 12 and the coil 2 is to move the movable part linearly in the theta direction. Therefore, one of the four sets of guide mechanisms can avoid the position of the coil 2, and four sets of car 11 mechanisms may be provided at two points in the length direction of the carriage 12, respectively.

Also, the guy 1 mechanism is connected to the coil 2 and the carriage 12.
The reason why four sets are provided at approximately equal angles on the outer periphery is to prevent the carriage 12 from rotating in a plane perpendicular to the theta direction, as described above.

However, the number of guide mechanisms is not limited to four, and may be any number that can prevent the movable parts such as the carriage 12 from rotating.

FIG. 7 is a diagram showing a second embodiment of the present invention.

In this embodiment, an air bearing is used as a guide instead of the bearing 4 used in the first embodiment, and the guide rail 13' is formed in the shape of a fin. Precise guide surfaces 19 are provided in the guide grooves 18 of the carriage guide 15 in very close proximity to both sides of the fin-shaped guide rail 13', and the high-pressure air supplied from the air supply hole 2o allows both sides of the fin-shaped guide rail 13' to be An air bearing is formed between the guide surface 19 and the guide surface 19, so that the entire movable part moves smoothly and with high precision.

As described above, in the above two embodiments, the shape of the carriage 12 is cylindrical, and its axis is the same as the axis of the coil 2, so that the electromagnetic force generated in the coil 2 can be directly transmitted to the head 1. Complex vibrations are less likely to occur and the vibration characteristics are improved, allowing highly accurate access. When the vibration characteristics were evaluated using a prototype device, the resonant frequency was 5~
It was good at 6KH2. Furthermore, since the shape is a simple cylinder, vibration analysis during manufacturing is easy, and manufacturing costs can be reduced. In addition, Carriage Guy 1-15
Since it is located outside the movable part and is relatively large, its rigidity can be easily increased and access accuracy can be improved. Furthermore, the movable parts are lightweight, allowing high-speed access.

〔Effect of the invention〕

As explained above, according to the present invention, the carriage has a cylindrical shape and the guide mechanism for the carriage is provided in one stage on the outside of the carriage, so that the structure is simple and easy to manufacture, and at high speed and high speed. An actuator that can be accessed with precision can be realized.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional actuator, FIG. 2 is a sectional view of FIG. 1 viewed from the X direction, and FIG.
A perspective view showing a movable part of an actuator according to an embodiment of
FIG. 4 is a sectional view of the actuator according to the first embodiment of the present invention, FIG. 5 is a diagram for explaining the state of the cross section taken along the line B-B in FIG. 4, and FIG. 6 is a cross-sectional view taken along the line C-- FIG. 7 is a cross-sectional view showing a '2nd embodiment of the present invention. 2: Voice coil motor coil, 4: Bearing, 6
: Permanent magnet of voice coil motor, 12: Carriage,
13. 13' guide rail, 15: Carriage guide, 16: Bearing support, 17: Spring, 18 Guide groove, 19: Guy 1 surface, 20: Air supply hole. '7J'J-1 Figure 2 Figure 3 / Figure 5 Figure 6 Figure 7 Continuation of Figure 1 [Phase] Inventor Yoshiyuki Hirano Kokubunji City Higashi-Koi Game Research Institute 0 Inventor Hiroshi Seo Right Kokubunji City Higashi-Koi Game Research Institute Inventor: Hiroshi Kawakubo - Kokubunji City Higashikoi Ke; Central Research Institute

Claims (1)

[Claims] (1) In an actuator for a magnetic disk drive that has a magnetic head, a carriage on which the magnetic head is mounted, and a voice coil motor that drives the carriage, the carriage has a cylindrical shape with the same diameter as the coil of the voice coil motor. , the cylindrical carriage and the coil are connected so that their respective axes coincide with each other, and a guide rail and a guide mechanism for supporting and guiding the guide rail are provided on the outside of the carriage. actuator.