JPH07287946A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To make a head arm inexpensive and mass-producible by making a head arm oscillating part of a self-aligning construction and simplifying the method for applying a preload to bearing. CONSTITUTION:The magnetic head arm 10 is equipped with an oscillating shaft part of two balls 16 force-fitted into a core tool 15 and arm main bodies 11A and 11B of press-formed articles calked at both ends of the core tool 15 respectively. A bearing part is a pivot ball bearing 5 inserted into steel plates respectively on the side of a base plate 2 and on the side of a yoke 3. The yoke 3 has an L-shape, and the pivot ball bearing 5 is inserted into an upper part of a vertical part in the figure, while a permanent magnet 4 is being held by its attracting force on the right side surface in a middle part of the vertical part, and then the right end surface of a horizontal part is brought into contact with the surface of the base plate 2. The yoke 3 is pressed and fixed to the base plate 2 via the magnetic attracting force worked between the yoke 3 and the base plate 2 by the permanent magnet 4, and at the same time, this attracting force becomes a preload to the pivot ball bearing 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to two spherical bodies provided on the arm main body of a magnetic head arm, in particular, a pair of rotary members for swinging the magnetic head arm, and a base plate side and two spherical bodies for supporting the spherical body from both sides. Self-aligning is possible with the pivot ball bearing provided on the yoke side, and the preload for the pivot ball bearing is constructed based on the magnetic attraction force of the permanent magnet of the voice coil motor, and the magnetic head arm is inexpensive. The present invention relates to a magnetic disk device having a mass-producible structure and having a size of 3.5 inches or less.

[0002]

2. Description of the Related Art In a conventional example, a magnetic head arm and a rotating pair part associated with its swing are constructed as follows. One of the magnetic head arms is a die-cast component whose arm body is made of an aluminum alloy or a magnesium alloy, and is subjected to precision machining. The other rotating pair, which is associated with swinging, has a structure in which a shaft processed with high precision is supported by two single-row deep groove type radial ball bearings provided on the arm body side. Further, in order to increase the rigidity of the radial ball bearing and remove the play, preload is applied as follows. That is, first the jig is used to position the radial ball bearing with respect to the housing on the arm body side, the adhesive is injected while applying preload to the outer ring or the inner ring, and after the adhesive is hardened, the jig is Remove.

[0003]

On the other hand, with respect to one magnetic head arm, there is a problem in that the arm body requires precision machining, resulting in high cost and poor mass productivity. As for the rotating pair part related to the other swing, since the radial ball bearings are positioned and bonded with an adhesive while applying a preload, the work is troublesome and requires skill and man-hours, and a jig is used. However, the positioning accuracy of the radial ball bearing with respect to the housing on the arm body side is difficult to obtain, and there is a problem that axial misalignment easily occurs (because it depends on the processing accuracy of the housing). In addition,
This axial misalignment is due to the smooth swinging of the magnetic head arm,
This becomes a factor that impairs the positioning accuracy with respect to the magnetic disk and eventually reduces the reliability of the device.

The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, to make the rotational pair associated with the swinging of the magnetic head arm self-centering, and to assemble the respective parts. It is an object of the present invention to provide a magnetic disk device having a simple structure for applying a preload to the bearing and a magnetic head arm having an inexpensive and mass-producible structure.

[0005]

SUMMARY OF THE INVENTION The present invention is a device in which an oscillating magnetic head arm is driven by a voice coil motor, and a rotating pair related to oscillating positions each center on an oscillating axis. And two spheres provided on the arm body of the magnetic head arm, and a pair of spheres are provided coaxially with the swing axis at parallel positions on the yoke side and the base plate side of the voice coil motor, respectively. It consists of a supporting pivot ball bearing.

Further, in the present invention, the yoke is L-shaped, the permanent magnet is provided on one of the linear portions, the one linear portion is parallel to the base plate, and the other linear portion is the swing axis line. They are positioned so that they are parallel to each other, and the magnetic attraction acting between the base plate and the permanent magnet causes the base plate to be directly attached to the base plate at the end face of one straight line portion and the set of the end portions of the other straight line portion and each pivot. It is pressed and fixed through the ball bearings. Furthermore, in the present invention, the magnetic head arm includes an arm body that is press-molded or plastic-molded, and a swinging core tool that is provided in the arm body and holds a sphere. Still further, according to the present invention, a magnetic head arm, two spheres provided on the magnetic head arm, and pivot ball bearings for supporting these spheres from both sides are arranged between the holding members fitted to the outer ring of each pivot ball bearing. It is composed of units by combining.

[0007]

According to the present invention, the two spheres provided on the arm main body of the magnetic head arm with their centers located on the swing axis are respectively provided on both sides of the sphere on the yoke side and the base plate side in parallel with each other. Since it is supported by the provided pivot ball bearing, the swing axis of the magnetic head arm is automatically aligned.

Further, in the present invention, the L-shaped yoke is positioned such that one straight line portion is parallel to the base plate and the other straight line portion is parallel to the swing axis, and magnetic attraction is exerted between the straight plate and the base plate based on the permanent magnet. The force is pressed and fixed to the base plate at the rotational pair position of the swing and the end surface position of the other straight portion, and a preload based on the magnetic attraction force is applied to the pivot ball bearing. Further, according to the present invention, the magnetic head arm having a rotating pair portion in which two spherical bodies provided on the magnetic head arm are swingably supported by the pivot ball bearings from both sides by coupling the holding members to each other.・ Unit is configured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic disk device according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an essential part of the embodiment, that is, a rocking bearing part of a magnetic head arm and its periphery. In the figure, the magnetic head arm 10
Has two sets of magnetic heads and can simultaneously support both surfaces of the magnetic disk 1. The magnetic head arm 10 includes a swinging shaft portion composed of a bushing-shaped core tool 15 and two balls 16 of steel balls lightly press-fitted therein, and each arm body 11A fixed by caulking to both ends of the core tool 15. , 11B and each arm body 11A,
The head unit 12 is connected to the tip of the 11B. The head unit 12 is an elastic plate member having a magnetic head at the tip. Right arm body
The coil 9 is attached to the lower part of the 11B in the figure. The swing bearing portion and each arm body 11A, 11B will be described in detail later.

The bearing portion that supports the swinging shaft portion of the magnetic head arm 10 is a pivot ball bearing 5 that is inserted into the base plate 2 side and the yoke 3 side, respectively. The base plate 2 is made of a steel plate which is a magnetic material. The yoke 3 is L-shaped, and the pivot ball bearing 5 is inserted at the upper end of the vertical part in the figure with the axis line horizontal, and the permanent magnet 4 is attracted or bonded to the right side surface (inner surface) of the middle part of the vertical part. It is fixed by an agent, and the right end surface of the horizontal portion is in contact with the left side surface of the base plate 2. As shown, the yoke 3 is positioned so that the vertical portion is parallel to the base plate 2 and the horizontal portion is parallel to the swing axis, and the magnetic attraction that acts between the yoke 3 and the base plate 2 is based on the permanent magnet 4. It is fixed to the base plate 2 by force. More specifically, the right end surface of the horizontal portion of the yoke 3 is directly pressed against the left side surface of the base plate 2, and the upper end portion of the vertical portion is pressed against the base plate 2 via the pivot ball bearing 5 and the ball 16. It is fixed without using any fastening means such as screws or adhesives. In addition, the base plate 2, the yoke 3, the permanent magnet 4, and the magnetic head arm
The coil 9 attached to the 10 constitutes a voice coil motor, and its driving moment causes the magnetic head arm to move.
10 is rocked. Magnetic disk 1 and magnetic head arm
10 and parts such as the pivot ball bearing 5 including the yoke 3,
It is covered and protected by the cover 8 from the left side.

Further, the embodiment will be supplementarily described with reference to the plan view of FIG. In FIG. 4, the magnetic head arm 10 is an axis line of the pivot ball bearing 5 inserted in the yoke 3.
A magnetic head that swings around (at right angles to the paper surface) and is fixed to the tip of each head unit 12 on the front side and the side not facing is a radial circle along each surface of the magnetic disk 1. Move in an arc. The coil 9 shown by the broken line is attached to the lower end of the arm body 11B on the opposite side in the figure (see FIG. 1). Note that cross-sectional views relating to the cross sections P-P and Q-Q shown in the drawings are FIGS. 2 and 3 described below.

FIG. 2 is a cross-sectional view of the rotating pair portion according to the swing of the embodiment, that is, a P-P cross-sectional view of FIG. A hole is coaxially formed at a swinging position of each arm body 11A, 11B of the magnetic head arm 10, and a machined or forged bushing-like core 15 is fixed by caulking. At both ends of this core 15, a bottomed hole is coaxially formed, and a ball 16 of a steel ball is lightly press-fitted into this hole. The two balls 16 form, so to speak, both ends of the pivot shaft. Two pivot ball bearings 5 are arranged coaxially with the axis connecting the centers of the balls 16 so as to support the set of balls 16 from both sides. The pivot ball bearing 5 is a mechanical element unit having a self-centering function, in which a plurality of balls 5a of small steel balls are housed in an outer ring 5b composed of a case and a lid. The right-hand pivot ball bearing 5 is fitted in the hole formed in the backing plate 6 and is inserted into the base plate 2, and the left-hand pivot ball bearing 5 is fitted in the hole formed in the frame 7. , Take a form to be inserted into the yoke 3. The support plate 6 and the frame 7 will be described below with reference to FIG.

FIG. 3 is another cross-sectional view of the rotating pair portion according to the swing of the embodiment, that is, a Q-Q cross-sectional view of FIG. In the figure, the receiving plate 6 is a stainless steel strip plate member, and the frame 7 is a U-shaped stainless steel plate member in which each leg end is bent at a right angle. Can be assembled. Insert the outer ring 5b of the pivot ball bearing 5 into the backing plate 6 and the frame 7, respectively, and hold the pair of balls 16 from each side by each pivot ball bearing 5 and lightly sandwich them so that no pressing force is applied.
At that time, the bent end of the frame 7 is brought into contact with the surface of the receiving plate 6, and this portion is joined by welding. Instead of welding, adhesion or screw fastening may be used. Assembled in this way, a unit composed of the magnetic head arm 10, the ball 16, the pivot ball bearing 5, the receiving plate 6 and the frame 7 is constituted. When the base plate 2 and the yoke 3 are arranged on both sides of this unit so as to be fitted to the outer rings 5b of the respective pivot ball bearings 5, as shown in FIG. 1, the base plate 2 and the yoke 3 have the permanent magnets 4 acting therebetween. It is fixed via the magnetic attraction force. Moreover, it is important that a preload based on this magnetic attraction force is applied to the pivot ball bearing 5. Therefore, as compared with the conventional example, the assembly of the rotating pair part and the method of applying the preload to the bearing part are accurate and easy, which facilitates the smooth swinging of the magnetic head arm 10 and the reduction of the assembly man-hours. .

By the way, each arm body 11A, 11B is a plate-shaped member made of a press-formed aluminum alloy, magnesium alloy or stainless steel, or a plastic-made plate-shaped member. This is caulked and fixed to the core 15 of stainless steel or brass that has been machined or forged with high precision. Therefore, it has the same or higher accuracy than the conventional die-cast arm body, and is further inexpensive and excellent in mass productivity.

[0015]

According to the present invention, the two units are provided on the arm body of the magnetic head arm with their centers located on the swing axis.
Since the individual spheres are supported by pivot ball bearings respectively provided on both sides of the sphere on the yoke side and the base plate side in parallel with each other, the swing axis of the magnetic head arm is automatically aligned. In addition, the L-shaped yoke is positioned such that one straight line portion is parallel to the base plate and the other straight line portion is parallel to the swing axis line. The pivotal pair bearing is pressed and fixed by the rotational pair portion of the swing and the end surface portion of the other straight portion, and a preload based on the magnetic attraction force is applied to the pivot ball bearing. Furthermore, a magnetic head arm unit having a rotating pair part in which two spheres provided on the magnetic head arm are swingably supported by the pivot ball bearings from both sides by connecting the holding members to each other. Composed.

Therefore, the swinging of the magnetic head arm can be performed smoothly and with high positioning accuracy with respect to the magnetic disk, and the reliability of the apparatus can be improved. Therefore, the number of parts required for assembling the swinging portion is reduced, and the number of assembling steps is reduced. In addition, the cost can be significantly reduced, the space can be saved, and the device can be downsized. Preloading the pivot ball bearing is accurate and easy, and the magnetic head arm can be swung smoothly and the number of assembly steps can be reduced. , The magnetic head arm consists of a press-molded or plastic-molded arm body and, for example, a swing core of a precision machined part or a precision forged part, compared to a conventional die-cast arm body. A rotary pair part for swinging the magnetic head arm, which has the same or better accuracy and is more inexpensive and mass-producible. From form consists in one of the units provided, assembled on, handling on the course quality control, the effect can be expected also convenient ── that from the standpoint of production management.

[Brief description of drawings]

FIG. 1 is a side view of an essential part of an embodiment according to the present invention.

FIG. 2 is a cross-sectional view of a rotating pair portion according to rocking of the embodiment.

FIG. 3 is another cross-sectional view of the rotating pair part according to the swing of the embodiment.

FIG. 4 is a plan view of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnetic disk 2 base plate 3 yoke 4 permanent magnet 5 pivot ball bearing 5a ball 5b outer ring 6 receiving plate 7 frame 8 cover 9 coil 10 magnetic head arm 11A, 11B arm body 12 head unit 15 core tool 16 ball

Claims (5)

[Claims] 1. An oscillating magnetic head arm is a device driven by a voice coil motor, wherein a rotating pair related to oscillating is located on an arm body of the magnetic head arm with each center positioned on an oscillating axis. It consists of two spheres provided, and a pivot ball bearing which is provided on each of the yoke side and the base plate side of the voice coil motor which are parallel to each other and is coaxial with the swing axis to support the set of spheres from both sides. Magnetic disk device characterized by. 2. The apparatus according to claim 1, wherein the yoke is L-shaped, one of which is provided with a permanent magnet, one of which is parallel to the base plate, and the other of which is linear. Are positioned so as to be parallel to the swing axis, and the magnetic attraction between the base plate and the base plate due to the permanent magnet causes the base plate to be directly attached to the end face of one of the straight portions and to the end portion of the other straight portion. A magnetic disk drive characterized in that each is pressed and fixed through a set of spheres and each pivot ball bearing. 3. The apparatus according to claim 1 or 2, wherein
The magnetic head arm is a press-molded arm body,
A magnetic disk device, comprising: a swing core member provided on the arm body to hold a sphere. 4. The device according to claim 1, wherein
The magnetic head arm includes a plastic-molded arm main body and a swinging core tool that is provided on the arm main body and holds a spherical body. 5. The apparatus according to claim 1, wherein the magnetic head arm, the two spherical bodies provided on the magnetic head arm, and the pivot ball bearings for supporting these spherical bodies from both sides are the same. A magnetic disk device comprising a unit formed by coupling holding members fitted to the outer ring of each pivot ball bearing.