JPH01300483A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent thermal off-track in a device from being generated by forming the receiving plane of a magnetic disk on the hub of a spindle motor in projecting circular arc shape, and providing notches continuing from the receiving plane of the disk on the side plane of the cylinder part of the hub. CONSTITUTION:The cross-secitonal shape of the working face of a hub flange part 27 with the magnetic disk 6 is formed in the same shape as the working face of a disk clamp 5 with the magnetic disk 6 by forming in the projecting circular arc shape, which changes face working to line working. In other words, it is constituted in such a way that the inclination of a disk plane does not depend on that of the working face of the hub flange part 27 with the magnetic disk 6. Next, the notches continuing with continuous planes from the projecting circular arc plane of the hub flange part 27 are provided on a hub cylindrical part 28, and a spring property is attached by thinning the thickness of a cylinder to connect the hub cylindrical part 27 to the hub flange part 27, thereby, the displacement of the hub flange part 27 can be prevented from affecting on the deformation of the shape of the hub cylindrical part 28. In such a way, it is possible to prevent the thermal off-track due to the inclination of the disk plane from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and in particular, to prevent the tilting of a magnetic disk recording surface due to changes in the environmental temperature of the device, and to prevent thermal occlusion caused by the tilting of the magnetic disk recording surface. The present invention relates to a magnetic dice laminated fixing structure suitable for preventing the occurrence of tracks.

[Conventional technology]

Regarding the magnetic disk stacked structure of conventional magnetic disk devices, a flange is provided at one end of the hub of the spindle motor that stacks the magnetic disks, the magnetic disk is placed on this flange, and then a disk spacer and the magnetic disk are placed on the hub. The magnetic disk is stacked alternately along the cylindrical part of the hub, and is secured from the other end of the hub with a disc clamp. The space between the cylindrical part and the hub had a rigid structure. An example of this is JP-A-61-121955.

This can be seen in Japanese Patent Application Laid-open No. 129765/1983.

[Problem to be solved by the invention]

In general, for stacking and fixing magnetic disks in a magnetic disk drive, a flange is provided at one end of the hub of the spindle motor that stacks the magnetic disks, and magnetic disks and disk spacers are alternately stacked on the hub as the bottom surface of this flange. A method is adopted in which it is fixed with a disk clamp from the other end. In this method, the disk clamp is fastened to the top of the hub with a screw, and the load generated by bending the disk clamp forces the magnetic disk and disk spacer downward, that is, against the flange surface of the hub, fixing the magnetic disk to the hub. . Looking at the materials that make up these parts, the magnetic disk, disk spacer, hub, and disk clamp are made of low-density materials such as aluminum to reduce weight, while the screws that fix the disk lamp are A material with high tensile strength, such as SCM, is used for this purpose.

If the environmental temperature of the device changes, the coefficient of thermal expansion of the components becomes an issue. Aluminum has a coefficient of thermal expansion of approximately 24.
x10'/℃, whereas SCM is 11 x 10
−”/℃, and there is a big difference between the two.For this reason,
For example, if the environmental temperature rises, the disk clamp, hub, magnetic disk.

Compared to the disk spacer, the amount of thermal expansion of the disk clamp fixing screw is smaller, and as a result, the amount of deflection of the disk clamp increases, resulting in an increase in clamp load. As the clamping load increases, the downward force applied to the hub flange surface increases, causing the hub flange surface to drop, and a moment is applied to the hub flange surface, causing the outer periphery of the flange surface to tilt downwards more than the inner periphery. Furthermore, this effect causes deformation in the vicinity of the flange of the hub cylindrical portion. As a result, especially when looking at the lowest magnetic disk that shines directly onto the flange surface, the disk surface will not be tilted to the hub flange, and the outer circumferential side of the magnetic disk will be lower than the circumferential side, which will cause This was one of the causes of thermal off-track in the equipment. The above explanation of the phenomenon is the same when the environmental temperature of the device decreases, and in this case, the clamping load of the disk clamp decreases due to the difference in the thermal expansion coefficient of the parts.
Due to the relative decrease in the force applied to the hub flange, the flange rises upward, and a moment is applied that tilts the outer circumferential side of the flange upwards more than the inner circumferential side, causing the flange surface to incline and the hub cylindrical section to tilt upward. Deformation occurs near the flange, and the outer circumferential side of the lowermost magnetic disk follows the flange surface and rises higher than the inner circumferential side, resulting in thermal off-track of the fruiting device.

An object of the present invention is to eliminate the above-mentioned inclination of the magnetic disk surface that occurs when the environmental temperature of the device changes, and to provide a structure in which the stacked magnetic disks are always kept parallel. The purpose is to prevent the occurrence of trucks.

[Means to solve the problem]

In order to achieve the above object, the following structure is adopted as a magnetic disk stacked structure. First, the cross-sectional shape of the contact surface of the hub flange with the magnetic disk is a convex arc, for example, a convex arc with a radius of 2.5+m+, which is the same shape as the contact surface of the disk clamp with the magnetic disk. By changing the contact with the magnetic disk from a surface light to a line light, the inclination of the disk surface is made to be independent of the inclination of the contact surface of the hub flange portion or the disk clamp with the magnetic disk. Next, a notch with a width Q of 5 mm and a depth of 1 m is provided in the hub cylindrical portion in a continuous plane from the convex arc surface of the hub flange, and the cylindrical wall connecting the hub cylindrical portion and the hub flange is made. By making the thickness thin, for example 1 m, spring properties are created between the hub cylindrical part and the hub flange part, so that the displacement and inclination of the hub flange part do not affect the shape deformation of the hub cylindrical part. Make it. Furthermore, the contact surface of the disk spacer with the magnetic disk is made into a flat shape as in the conventional example, and the contact between the disk spacer and the magnetic disk is surface contact, and the inclination of the disk surface follows the surface of the disk spacer, so that each disk surface It also has the function of maintaining a parallel relationship with both. By adopting the above structure,
Even when the environmental temperature of the device changes, the stacked magnetic disks are always kept parallel to each other to prevent the occurrence of thermal off-track due to the inclination of the disk surface.

[Effect]

The behavior of the magnetic disk stacked structure of the present invention when the environmental temperature changes will be explained. When the environmental temperature rises, the clamping load of the disk clamp increases due to the difference in thermal expansion coefficients of the parts as described above. As a result, the downward force applied to the hub flange surface increases and the hub flange surface lowers, and a moment is applied to the hub flange surface, causing the inner peripheral side of the flange surface to tilt downward. At this time, in the magnetic disk laminated structure of the present invention, as described above, by reducing the thickness of the cylinder that connects the hub cylinder part and the hub flange part, springiness is imparted between the hub cylinder part and the hub flange part. Therefore, the effects of the drop of the flange surface and the inclination of the flange surface are absorbed by this thin, springy portion and do not cause deformation of the hub cylindrical portion.

That is, the deformation of the hub cylindrical portion near the flange caused by the lowering and inclination of the flange surface, which was observed in the conventional example, does not occur in the structure of the present invention. In addition, the cross-sectional shape of the contact surface of the hub flange part with the magnetic disk is a convex arc shape, and the hub flange part and the magnetic disk are in line contact, so the bottom disk surface is in contact with the top surface. It follows the surface of the disk spacer, and the disk spacer does not tilt because the hub cylindrical portion is not deformed as described above. Therefore, the behavior of the bottom disk surface is no longer tilted, but only parallel movement, and the same amount of parallel movement occurs for the heads laminated on the aluminum carriage bridge. As a result, the relative positional relationship between the disk surface and the head can be maintained at the same position as before the temperature change, and the occurrence of thermal off-track due to the inclination of the disk surface can be prevented. The other magnetic disks and disk spacers are also stacked on the bottom magnetic disk and the disk spacer above it, and there is no inclination, and the other disk spacers are guided by the hub cylindrical part, and Since the influence of the inclination of the hub flange part is removed from the hub cylindrical part, each magnetic disk follows the surface of the disk spacer which is in parallel contact with each other. The disc surface will no longer tilt. Furthermore, regarding the contact between the uppermost magnetic disk and the disk clamp, as with the lowermost magnetic disk and the hub flange,
By making the cross-sectional shape of the contact surface of the disk clamp with the magnetic disk into a convex arc shape, and by making the uppermost magnetic disk and the disk clamp in line contact, the uppermost disk surface is in contact with the surface of the disk spacer that is in contact with the surface below. That will happen. As mentioned above, since each disk spacer maintains a parallel relationship, the uppermost disk surface will not tilt due to temperature rise. For these reasons, the multiple stacked magnetic disks are no longer tilted and only move in parallel, and the relative positional relationship between the disk surface and the head becomes the same position as before the temperature change, similar to the bottom disk surface described above. This makes it possible to prevent thermal off-track from occurring due to the inclination of the disk surface.

The above description of the phenomenon is also the same when the environmental temperature of the device decreases. In this case, the clamping force of the disk clamp decreases due to the decrease in environmental temperature, which causes the hub flange surface to rise and the outer periphery of the flange surface to be tilted upwards than the inner periphery.However, as mentioned above, the hub cylindrical Due to the springiness provided between the hub flange and the hub flange, no deformation occurs on the hub cylindrical surface. Therefore, the multiple magnetic disks that are in close contact with each disk spacer are stacked on the hub cylindrical surface while maintaining parallel states, and the bottom magnetic disk and the top magnetic disk are stacked on the hub flange surface and the disk clamp respectively. Because they are held in place by a straight line, they are not affected by the inclination of the hub flange surface or disc clamp. For these reasons, any of the plurality of stacked magnetic disks will not suffer from thermal off-track due to the inclination of the disk surface when the environmental temperature of the device decreases.

As described above, according to the magnetic disk stacked structure of the present invention, a plurality of stacked magnetic disks can always be maintained in parallel even when the environmental temperature of the device changes, and the relative positional relationship between the disk surface and the head can be maintained. Since it is possible to maintain the same position as before the temperature change, it is possible to prevent the occurrence of thermal off-track in the device caused by the inclination of the magnetic disk surface.

〔Example〕

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

FIG. 7 is a perspective view showing the entire device. The cover 1 and the base 2 are screwed together, and a head disk assembly (hereinafter referred to as HDA) is constructed by incorporating a plurality of magnetic heads, a plurality of magnetic disks, and two mechanism circuits for controlling and controlling both of them. (abbreviated as ).

The HDA is attached to the frame 3 via a vibration isolating rubber 21 to prevent frame vibrations from being transmitted to the HDA. Further, a package board 4 is attached to the lower part of the base 2 for data transfer with a host model and for activating and controlling the magnetic disk device.

FIG. 8 is a diagram showing the internal structure of the above-mentioned IDA. The base 2 includes a spindle motor 8 and a pivot base 9.
is fixed with screws. A predetermined number of magnetic disks 6 and disk spacers 7 are alternately stacked on the hub 22 of the spindle motor 8 and fixed by a disk clamp 5. At this time, the disc clamp 5 is fastened to the hub 22 via the screw 23, and at this time, a clamping load is generated due to the deflection of the disc clamp 5. The magnetic disk 6 and the disk spacer 7 are fixed by pressing the cylindrical surface of the hub 22 downward against the guide by this clamp load. On the other hand, a carriage assembly 16 equipped with a magnetic head 11 having a head core 10 for writing and reading data on the magnetic disk 6 is inserted into the pivot base 9, and controls the current flowing to the coil 19 of the voice coil motor 20. By doing so, the carriage assembly 16 is rotated around the shaft, and the head core 1o is attached to the magnetic disk 6.
Move 2 to an arbitrary radial position. The magnetic head 11 maintains its posture above the magnetic disk 6 by a gimbal spring 12, and is pressed onto the recording surface of the magnetic disk 6 by a load arm 13. The load arm 13 is fixed to a head arm 14, and the head arm 14 is stacked on a carriage hub 24 and fixed by a head clamp 15. The carriage hub 24 is fixed to the shaft of the pivot base 9 via a bearing, and with the above configuration, the magnetic heads 11 are stably supported on the recording surface of each predetermined magnetic disk 6. Furthermore, carriage assembly 16
A read/write amplifier board 17 on which read/write amplifiers 1 to 1 are mounted is fixed to the side surface of the HDA, and data signals and carriage assembly control signals are led out to the outside of the HDA through a flexible printed circuit 18.

H
Configure DA. At this time, the shaft 25 of the spindle motor 8 and the shaft 26 of the pivot base 9 are also connected to the cover 1.
Screws are tightened from the top of the shaft to support both ends of the shaft.

An embodiment of the magnetic disk stacked structure of the present invention in the above magnetic disk device will be described next.

FIG. 1 shows an embodiment of the magnetic disk stack structure of the present invention. Further, FIG. 2 shows an enlarged view of the flange portion 27 of the hub 22 of the embodiment and the vicinity of the flange portion 27 of the cylindrical portion 28 of the hub 22. Examples will be explained as follows. First, the magnetic disk 6 of the hub flange portion 27
The cross-sectional shape of the contact surface is a convex arc, for example, radius 2.5
The hub flange portion 27 has the same convex arc shape as the contact surface of the disk clamp 5 with the magnetic disk 6.
By making the contact between the magnetic disk 6 and the magnetic disk 6 linear, the inclination of the disk surface is made independent of the inclination of the hub flange portion 27 and the disk clamp. Next, in the hub cylindrical portion 28, make a thin cut that continues in a continuous plane from the convex arc surface of the hub flange portion 27, for example, a width of 0.5 +.
nm and depth Im, and the wall thickness of the cylinder connecting the hub cylindrical part 28 and the hub flange part 27 is reduced, for example, by 1 m.
By setting m, spring properties are provided between the hub cylindrical portion 28 and the hub flange portion 27, so that the displacement and inclination of the hub flange portion 27 do not affect the shape deformation of the hub cylindrical portion 28. do.

Furthermore, the contact surface of the disk spacer 7 with the magnetic disk 6 is made into a planar shape similar to the conventional example, and the inclination of the disk surface follows the surface of the disk spacer 7, maintaining a parallel relationship with each disk surface. Make it functional.

FIG. 5 shows the behavior of the magnetic disk surface when the environmental temperature changes in the above-described embodiment of the magnetic disk stacked structure. The disk clamp 5 is fastened to the upper surface of the hub 22 with a screw 23, and the load generated by bending the disk clamp 5 forces the magnetic disk 6 and disk spacer 7 downward, that is, against the flange portion 27 of the hub 22, and the magnetic disk 6 is pressed against the hub 22. It is fixed at 22. The materials and thermal expansion coefficients of the parts that make up these parts are as follows: the magnetic disk 6, the disk spacer 7, the hub 22°, and the disk clamp 5, which is made of aluminum and has a coefficient of 24 x 10-
'/'C, the screw 23 is SCM435 (chromium molybdenum steel) and has a temperature of 11X10-'/°C. Due to this difference in thermal expansion coefficient, for example, when the environmental temperature rises, the disc clamp 5, the hub 22. The amount of thermal expansion of the screw 23 is smaller than that of the magnetic disk 6 and the disk spacer 7, and as a result, the amount of deflection of the disk clamp 5 increases, thereby increasing the clamping load. When the clamp load increases, the downward force applied to the flange portion 27 of the hub 22 increases, and as the hub flange portion 27 lowers, a moment is applied to the hub flange portion 27, and the outer circumferential side of the flange surface is stronger than the inner circumferential side. It will tilt downward. At this time, as described above, the hub cylindrical portion 28 and the hub flange portion 27
Since a spring property is provided between the hub cylindrical part 28, the influence of the lowering of the flange part 27 and the inclination of the flange part 27 is absorbed by the part provided with the spring property, and the hub cylindrical part 28 is not deformed. . In addition, the cross-sectional shape of the contact surface of the hub flange portion 27 with the magnetic disk 6 is a convex arc shape as shown in the figure, and since the hub flange portion 27 and the magnetic disk 6 are in line contact, the lowermost disk surface is It will follow the surface of the disk spacer 7 that is in contact with the top surface,
Furthermore, the disk spacer 7 is attached to the hub cylindrical portion 28 as described above.
It does not tilt because no deformation occurs. For this reason, the fifth
As shown in the figure, the bottom disk surface no longer tilts, and the behavior of the bottom disk surface is only parallel movement. The amount of parallel displacement is offset by the same amount of parallel displacement occurring in the magnetic head 11 stacked on the carriage hub 24, which is also made of aluminum like the hub 22, and as a result, the relative displacement between the disk surface and the head is The positional relationship can be maintained at the same position as before the temperature change. The above-mentioned action can prevent the occurrence of thermal off-track due to the inclination of the disk surface. The other magnetic disks 6 and disk spacers 7 are also stacked on the lowermost magnetic disk 6 and the disk spacer 7 above it, and are not tilted. The condition is that the hub cylindrical part 28 is guided by the hub flange part 27 and that the influence of the inclination of the hub flange part 27 is removed. 7, and the disk surface will not tilt due to temperature rise. Furthermore, as for the uppermost magnetic disk 6, since the contact with the disk clamp 5 is linear, the uppermost disk surface follows the surface of the disk spacer 7 which is in contact with the disk spacer 7 below. The surface of the uppermost magnetic disk 6 does not tilt.

From the above, as shown in FIG. 5, the predetermined number of stacked magnetic disks 6 can maintain a parallel relationship even when the environmental temperature of the device increases, and the relative positional relationship between the disk surface and the head. Since it is possible to maintain the same position as before the temperature change, thermal off-track due to the inclination of the disk surface does not occur.

The above description of the phenomenon is also the same when the environmental temperature of the device decreases. In this case, the clamping force of the disk clamp 5 decreases due to the decrease in the environmental temperature, and as a result, the hub flange portion 27 rises and the outer circumferential side of the flange portion 27 tilts upward more than the inner circumferential side. However, as described above, due to the springiness provided between the hub cylindrical portion 28 and the hub flange portion 27, the hub cylindrical portion 28 is not deformed. As a result, the same behavior as in the case where the environmental temperature rises (FIG. 5(a)) occurs, and as a result, as shown in FIG. When decreasing (
The parallel relationship can also be maintained in Figure 5 (b)), and the relative positional relationship between the disk surface and the head can be maintained at the same position as before the temperature change, so thermal off-tracking due to the inclination of the disk surface occurs. Never.

FIGS. 3 and 4 show the magnetic disk stack structure of the conventional example, and FIG. 6 shows the behavior of the magnetic disk surface in the conventional example when the environmental temperature of the apparatus changes.

In the conventional example, the hub flange portion 27 and the magnetic disk 6 are flat, and the space between the hub cylindrical portion 28 and the hub flange portion 27 is rigid. Therefore, for example, when the equipment environment temperature rises above H, an increase in the clamping load applies a downward force to the hub flange portion 27 as shown in FIG. The tilting moment is very bad. For this reason, deformation occurs including the vicinity of the flange portion 27 of the hub cylindrical portion 28, and the magnetic disk 6 and disk spacer 7 are affected by these deformations. In particular, the disk surface of the lowermost magnetic disk 6 has its outer circumference lower than its inner circumference. There is a stronger tendency towards this than other magnetic disks. When the device environment temperature decreases, the opposite displacement occurs as shown in FIG. 6(b), and the disk surface of the lowermost magnetic disk 6 becomes
As a result, the outer circumference is tilted higher than the inner circumference. As described above, in the conventional example, the disk surface tilts due to changes in the ambient temperature of the device, which causes thermal off-track in the device.

As described above, according to the present invention, even when the environmental temperature of the device changes, the disk surfaces of each magnetic disk 6 can maintain a parallel relationship with each other, and the relative positional relationship between the disk surface and the head can be maintained. Since it is possible to maintain the same position as before the temperature change, it is possible to prevent the occurrence of thermal off-track due to the inclination of the disk surface.

〔Effect of the invention〕

According to the magnetic disk stacked structure of the present invention, even if the environmental temperature of the magnetic disk drive changes, the relationship between the stacked multiple magnetic disks can always be maintained parallel to each other, so the relative relationship between the disk surface and the head can be maintained. Since the positional relationship can be maintained at the same position as before the temperature change, it is possible to prevent thermal off-track of the device caused by the inclination of the magnetic disk surface.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic disk laminated structure according to an embodiment of the present invention, FIG. 2 is an enlarged view of the hub flange portion in FIG. 1, and FIG. 3 is a cross-sectional view of a conventional magnetic disk laminated structure. Fig. 4 is an enlarged view of the hub flange portion in Fig. 3, Fig. 5 is an explanatory diagram of phenomena related to disk surface behavior when the environmental temperature of the device according to an embodiment of the present invention changes, and Fig. 6 is an illustration of the conventional example. FIG. 7 is a perspective view of the entire apparatus according to an embodiment of the present invention, and FIG. 8 is an explanatory diagram showing the internal structure of the Herad disk assembly of FIG. 7. 1. Cover, 2. Base, 3. Frame, 4. Package board, 5. Disk clamp, 6. Magnetic disk, 7. Disk spacer.
8 ・Spindle motor, 9... Hiho 1 base,
10. Head core, 11. Magnetic head, 12 Gimbal spring, 13 Load arm, 14. Hella door 11.
15. Head clamp, 16. Carriage assembly, 17. Read/write amplifier board, 18. Flexible printed circuit, 19.
Coil, 20 Voice coil motor, 21 Anti-vibration rubber, 22 Hub, 23
Screw, 24 Carriage hub, 25 - Shirt 1 ~ (spindle motor), 26 - Shaft (pivot base), 27 - Hub flange part, 28... Hub cylindrical part, 29 Notch.

Claims (1)

[Claims] 1. A disk-shaped magnetic disk for recording information, a spindle motor for stacking and clamping a plurality of the magnetic disks on a hub and rotating the hub and the magnetic disk at a constant rotation speed; A magnetic head for writing and reading data on the magnetic disk, a gimbal spring for keeping the magnetic head stable, and a load arm for pressing the magnetic head onto the magnetic disk and making it fly at a constant flying height. , a head arm for fixing the load arm, a carriage for fixing the head arm, a coil installed on the carriage, and a motor configured by the coil and a permanent magnet circuit, thereby rotating the load arm. A mechanism for positioning the magnetic head at an arbitrary radial position on the magnetic disk is configured, and the spindle motor and each shaft, which is a center of rotation of the carriage, have a structure in which both upper and lower ends are supported and fixed to a base and a cover, respectively. In the magnetic disk drive having the above, the shape of the magnetic disk receiving surface of the hub of the spindle motor is made into a convex arc shape to be equal to the shape of the magnetic disk contacting surface of a disk clamp for clamping the magnetic disk, and
By providing a notch continuous from the disk receiving surface on the side surface of the hub cylindrical portion, spring properties are imparted between the disk receiving surface and the hub cylindrical portion, and the shape of the magnetic disk contacting surface of the disk spacer is flat. A magnetic disk device with a characteristic magnetic disk stacked structure.