JPH043027B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic disk storage device awaiting a magnetic head positioning mechanism, and particularly to cooling of a positioning mechanism section within an enclosure of a self-circulating magnetic disk storage device. The present invention relates to a magnetic disk storage device having a novel positioning mechanism that uniformizes temperature distribution and efficiently removes internal foreign particles.

[Background of the invention]

In recent years, 8.0
Small magnetic disk storage devices using inch diameter, 5 inch diameter and 3 inch diameter magnetic disks are becoming popular. Magnetic disk storage devices have the same physical and electrical interfaces as flexible disk devices, making it possible to design highly compact, high-density, high-capacity magnetic disk storage devices. must be developed. Such miniaturized high-density, large-capacity magnetic disk storage devices are technically more difficult than large-sized magnetic disk storage devices. Under these circumstances, 5-inch magnetic disk storage devices with small capacity and relatively slow access times have entered the market, but in the market, 5-inch magnetic disk storage devices with small capacities and relatively slow access times are becoming popular. The demand for compact, energy-saving equipment is becoming increasingly strong, and companies are competing with each other to advance their development.

Conventional compact magnetic disk storage devices of about 5 inches have low storage density, and because they do not use a servo positioning method, they have a large track interval margin and the spindle and magnetic head positioning mechanism are slightly tilted, resulting in off-track phenomenon (thermal Even if there is a deviation from the desired track address position due to displacement, etc., making it impossible to read the desired track address information, it is possible to read up to about 10 μm without any problem, and there is no servo head even if the spindle housing rigidity is a little small. Therefore, servo vibration is not generated. On the other hand, in order to achieve high density at low cost, the track spacing and track width must be made very small. As a result, the track spacing margin becomes a small value of about 1.5 μm. Therefore, off-track phenomena caused by temperature changes or temperature distribution differences, which would not be a problem when the recording density is low and the track spacing margin is relatively large, become a problem. This phenomenon is caused not only by the inclination of the spindle as described above, but also by the thermal displacement of the magnetic head positioning mechanism that accesses and positions the servo head at high speed, causing an off-track phenomenon.

A typical example of such a magnetic head positioning mechanism is described in Japanese Patent Laid-Open No. 47-32809. In the magnetic head positioning mechanism memorized in this publication, the carriage support member has a 〓-shape, so it is deformed into a 〓-shape (thermal displacement) due to temperature distribution differences or temperature changes within the sealing body.
This causes the pivot shaft, which is the support shaft that allows the carriage to rotate, to tilt. The reason for this difference in temperature distribution is that the temperature inside the sealed body rises by approximately 15 degrees Celsius due to wind damage caused by the rotation of the magnetic disk, etc.
Moreover, this temperature increase is not uniform within the seal, creating a temperature gradient, for example, between the base member surface and the seal cover. For this reason, thermal displacement occurs at the top and bottom of the cross-shaped member of the carriage support member (made of aluminum or the like), causing the pivot shaft to tilt. In addition, since it has a square shape, the upper part of the square that supports the pivot shaft, which is a rotational support shaft, has a cantilevered structure and has low rigidity, so the natural frequency also forms a sealed body. The frequency approaches the natural frequency of the mechanical part and magnetic head, which induces servo head vibration. Further, in this publication, a rotary positioning structure using a voice coil motor is adopted in order for the magnetic head positioning mechanism to access the magnetic head at high speed and perform accurate positioning.
For this reason, pure iron is mainly used as the material for each yoke that constitutes the magnetic circuit that is the drive source for the voice coil. Since such iron-based material is attached to the side surface of the above-mentioned shape-shaped carriage support member (made of light alloy such as aluminum), thermal deformation occurs due to the bimetallic effect due to the bonding of dissimilar metals, and as a result, the carriage support member Thermal deformation occurs and the pivot shaft, which is the pivot shaft, becomes tilted.
Furthermore, when current is supplied to the voice coil,
The carriage member is accessed and positioned at high speed so as to rotate in the radial direction of the magnetic disk by the electromagnetic force generated between the voice coil and the magnetic flux forming portion of the magnetic circuit. For this reason, the voice coil and magnetic circuit section will experience an extreme temperature rise. In this publication, since the magnetic circuit section is configured to be fastened to the carriage support member as described above, the temperature of the carriage support member is extremely high compared to other parts, and the temperature of the carriage support member or This results in thermal displacement of the base member.
As a result of the tilting of the pivot shaft due to each of the above-mentioned factors, the magnetic head deviates from the reference position and an off-track phenomenon occurs, and the above-mentioned factors also induce a servo head vibration phenomenon.

Furthermore, the parts housed in the sealing body of the head disk assembly of a magnetic disk storage device using hard magnetic disks must be clean. Further, foreign particles must not be generated inside the sealing body or foreign particles must not enter from the outside. This means that between the magnetic disk surface and the magnetic head surface,
It floats due to the air bearing effect while maintaining a flying height of 0.5 μm, and if a foreign particle gets between the magnetic disk surface and the magnetic head surface, which are rotating at high speed in close proximity, it can cause damage to the magnetic disk surface. It becomes impossible to read or write information to the magnetic disk surface through the magnetic head. For this reason, the parts housed in the sealed body are usually subjected to ultrasonic washing and cleaning, and all the assembled parts are assembled in a very clean atmosphere in a dust-proof room.

However, even if assembly work is carried out with such care, a certain amount of foreign particles will still be present, which will significantly impair the reliability of the device, so it is necessary to remove even extremely small amounts of foreign particles. be. Conventional magnetic disk storage devices of this type are mainly based on self-circulating air systems. This self-circulating air system circulates air (pumping effect) using a pressure difference between the inner and outer circumferences of a magnetic disk rotating at high speed within the sealed body. This is because it is necessary to quickly and completely remove foreign particles within the sealed body and to circulate the air inside the sealed body in order to keep the temperature within the sealed body constant. This kind of structure is
For example, it is described in Japanese Patent Application Laid-open No. 159879/1983.

In order to make this system compatible and replaceable with flexible disk devices, there is a size limit on the height of the device itself, and the air circulation method is to circulate on the side of the base member at the bottom of the device. ing. In this method, air flows in from the bottom of the hub where the spindle shaft is attached, multiple through holes are provided on the side of the hub, and multiple through holes are provided in multiple disk spacers to circulate the internal air. Things are the subject. However, this method creates a very negative pressure between the outer diameter of the spindle housing and the hub, so the high-speed rotation of the spindle bearing can cause oil droplets from the base oil of the bearing grease, and foreign particles can flow into the sealing body from the outside. This will encourage Furthermore, the plurality of through holes provided in the side surface of the hub reduce the rigidity of the hub and cause vibration. A structure similar to this is published in JP-A No. 47-32809.
It is also stated in the publication.

Furthermore, in the conventional device, the structure is such that airflow generated by the rotation of the magnetic disk does not easily flow around the magnetic head positioning mechanism housed in the sealed body, so that air pockets occur around the positioning mechanism. As described above, this reduces the air circulation efficiency within the sealed body, reduces the dust collection efficiency, and makes the temperature distribution within the sealed body uneven. Furthermore, since the voice coil motor, which is a heating element, is housed in the sealed body, the temperature of the part where high-precision positioning is performed is extremely high. This will lead to an off-track phenomenon. As mentioned above, conventional devices have various drawbacks.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk storage device that can improve the air circulation efficiency within the sealed body of the magnetic disk storage device and keep the temperature inside the sealed body constant.

Another object of the present invention is to reduce the local temperature rise of the voice coil motor section, which is a heat source within the sealed body.

[Summary of the invention]

In order to achieve these objects, the present invention has a carriage (movable member) that fixes a magnetic head at one end and moves the magnetic head to a predetermined position on a magnetic disk, a coil attached to the other end of the carriage, and a magnetic head. In a magnetic disk storage device having a non-movable member consisting of a circuit section and a carriage support member, fins are formed in the portion of the non-movable member facing the magnetic disk. The shape of the fins is, for example, formed in a direction extending in a direction parallel to the disk surfaces, and is shaped to extend and be inserted between a plurality of disks.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic disk storage device having a high-precision magnetic head positioning mechanism according to the present invention will be described in detail below with reference to the drawings.

(A) In the magnetic disk storage device according to this embodiment, as shown in FIGS. 1 and 2, a magnetic disk assembly 1 is attached and fixed to a rotation drive section 2. The rotation drive unit 2 includes a magnetic disk drive motor 3
and spindle portion 4 are integrally constructed.
In addition, in order to obtain high-speed and accurate rotation, a pair of ultra-precision bearings 6 and 7 are used to support the spindle shaft 5 above and below, and to ensure accurate positioning of the bearings 6 and 7 in the radial and axial directions. Appropriate preload is applied by spring 8 to suppress vibration and increase the rigidity of bearings 6 and 7. The spindle housing 9 has a linear expansion coefficient of the iron-based cylindrical spindle housing 100, which is the first member, of the bearing 6,
Use a ferrous material (for example, stainless steel, etc.) that is equivalent to the material of the outer ring in item 7. Therefore, even if there is a temperature change, the first member 100 and the bearings 6, 7
Since the amount of thermal displacement is the same, no gap is generated between the two, and it is possible to prevent the spindle shaft 5 from tilting due to thermal displacement. Further, the first member 100 is made of iron-based material and has a cylindrical shape to increase the rigidity of the housing.

Therefore, the natural frequency of the spindle portion 4 can be increased, and the influence on servo vibration can also be reduced. Since the second member 101 of the spindle housing 9 is a member for fixing and fastening the spindle portion 4 to the base member 10, it is necessary to prevent thermal deformation (bimetal effect) of the base member 10 due to a difference in coefficient of linear expansion. The same aluminum material (for example, aluminum die-casting, etc.) is used. By eliminating dissimilar combinations of metals in this way,
The base member 10 is thermally deformed due to the bimetal effect, and the relative position between the magnetic head positioning mechanism mounted on the base member 10 and the magnetic disk 11 does not change, and off-track phenomenon can be prevented. At the same time, the off-track phenomenon caused by the inclination of the spindle shaft 5 can also be prevented.

Further, in order to fix and rotate a plurality of magnetic disks 11 on the number of times drive unit 2 configured as described above, a hub 1 is installed on the upper part of the spindle shaft 5.
2 is fastened by shrink fitting or the like. In order to prevent the scattering of the base oil droplets of the bearing grease generated by the high speed rotation of the bearings 6 and 7, a grease material is selected for the part connected to the hub 12, and a grease type with less base oil droplets is used. With,
In addition, a non-contact magnetic sealing member 200 is provided to prevent foreign particles from entering the sealing body 13 due to temperature and pressure differences between the external atmosphere and the inside of the sealing body 13.
is provided between the spindle shaft 5 and the spindle housing 9, and a sealed structure is adopted to prevent oil droplets, external foreign particles, etc. from entering the sealing body 13 of the head disk assembly.
In addition, in this embodiment, as an air circulation system within the sealing body 13 of the head disk assembly,
By providing a hole 22 in the disk clamp 21 for positioning and fixing the magnetic disk 11 and disk spacer 16 without allowing air to flow in from the lower part of the hub 12, the sealing body 1
A method is adopted in which air is introduced from the upper part of the magnetic disk 3 onto the surfaces of the plurality of magnetic disks 11. In order to guide air from the hole 22 onto the surface of the magnetic disk 11, the structure is as follows.

(B) That is, in this embodiment, the hub 12
The outer circumferential side surface 20 of the magnetic disc 11 is an inclined surface, and a tapered air flow path is formed between the plurality of magnetic disks 11 and the guide portion 19 that positions and guides the plurality of disk spacers 16. The air flow path is tapered, and the flow path is wide at the top where the airflow is high, and narrow at the bottom where the airflow is low, so that an appropriate airflow is conducted between the 11 surfaces of each magnetic disk. It will be destroyed. Further, the guide portion 19 is formed in a convex shape and serves as an impeller. Therefore, the convex guide portion 19 also provides an appropriate amount of circulating air. Furthermore, the hub 12 has a wall thickness that does not reduce rigidity, and is rib-shaped to further increase rigidity. A plurality of through holes 17 are provided in each disk spacer 16 in order to guide air from the tapered airflow passage onto the surface of each magnetic disk 11. The air inside the sealing body 13 passes through the tapered air flow path from the hole 22 of the disk clamp 21, passes through the through hole 17 of the disk spacer, passes between the surfaces of the magnetic disk 11, and passes through a dust filtering mechanism (not shown). Since the air circulates back to the through hole 22 and there is no need to provide a through hole for air circulation in the hub 12 as in conventional mechanisms,
The rigidity of the hub 12 is not reduced. Further, since there is no circulation of air between the outer diameter of the spindle housing 9 and the hub 12, negative pressure does not develop on the bearing side of the spindle portion 4. Therefore, the bearing 6,
The flow of oil droplets of the base oil No. 7 or foreign particles from the outside of the sealing body 13 into the sealing body 13 of the head disk assembly is suppressed and at the same time is completely blocked by the magnetic seal member 200.

(C) Inside the sealing body 13 of the head disk assembly configured as described above, the novel magnetic head positioning mechanism 24 of this embodiment is installed on the base member 1.
0, further enhancing the above effect. FIG. 1 shows a plan view of a head disk assembly of a magnetic disk storage device according to an embodiment of the present invention with a sealing body cover removed, and FIG. 2 shows a partial sectional view of the device. Figures 1 and 2
In the figure, an access arm 26 on which a plurality of magnetic heads 23 are mounted is connected to the carriage member 25 at one end, and a voice coil section 27 at the other end.
The rotation support shaft of the pivot shaft 28 is disposed at the center of gravity of these two parts. In this embodiment, a rotary positioning mechanism is employed. In this rotary positioning mechanism, since the magnetic head 23 moves in an arc on the surface of the magnetic disk 11, the magnetic head 23 moves on the track on the magnetic disk 11 (on the circumference where desired information is written or read). The disadvantage is that the magnetic disk surface always tilts by a small angle (hereinafter referred to as yaw angle) with respect to the tangential direction of the magnetic disk surface (there are several hundred tracks/surface). The occurrence of this yaw angle causes instability in the flying height of the magnetic head 23, causing the magnetic head 23 to become unstable.
3 and the magnetic disk 11, as well as inducing a head crushing phenomenon and a head vibration phenomenon.
Since the track width to be read substantially differs between the inner and outer peripheries of the magnetic disk 11, a phenomenon occurs in which instability is induced in the information recording/reproducing signal. Experiments have shown that the limit for these phenomena is a yaw angle of 13 degrees.
Therefore, in this embodiment, the yaw angle is set small when the magnetic head 23 is floating on the inner circumference side, and the yaw angle is set large on the outer circumference side, where the peripheral speed is fast, the flying height is high, and the recording and reproducing characteristics are relatively good. is designed to. In addition, in order to balance the first moment between the magnetic head 23 side and the voice coil section 27 side around the pivot shaft 28, which is a rotation support shaft, the voice coil bobbin section 29 is provided with a counter mass (brass etc. in the embodiment). (not shown in the figure) is attached. Therefore, the device can be operated in any mounting direction, and a carriage lock to prevent problems caused during transfer is unnecessary, making it possible to manufacture the device at low cost. Further, a pivot shaft 28, which is a pivot shaft for the carriage member 25, is fastened onto a carriage support member 31. The main carriage support member 31 of the present invention is a member for fastening the magnetic head positioning mechanism 24 onto the base member 10, and is a member for fastening the magnetic head positioning mechanism 24 onto the base member 10.
In order to prevent thermal deformation due to the bimetallic effect, the base member 10 is made of the same material. Since the carriage support member used in the conventional device has a cross-shaped shape as described in Japanese Patent Laid-Open Publication No. 47-32809, it has the above-mentioned drawbacks. The present invention provides a novel magnetic head positioning mechanism 24 that overcomes these drawbacks.

(D) Novel carriage support member 3 according to this embodiment
1 has a gate post shape as shown in FIGS. 3, 4, and 5 as a means to prevent tilting due to thermal displacement, so that the pivot shaft 28, which is a pivot shaft, does not tilt. , eliminating the need to fasten the magnetic circuit section 38, which is the drive source of the voice coil 30, to the flat surface of the carriage support member 31 using the three screws shown in the figure, and fasten it to the side surface of the gatepost section of the support member 31. are doing. The magnetic circuit section 38 is composed of two permanent magnets, one center yoke, and a pair of side yokes, and further includes a closed loop member in order to reduce magnetic flux leakage and downsize the magnetic circuit. A rotating closed loop magnetic circuit 38 is formed. The material of each of the yokes constituting the magnetic circuit 38 is designed to mainly use pure iron. When such iron-based material is attached to the side surface of the gate post shape (〓 shape), thermal deformation occurs due to the bimetallic effect due to the dissimilar combination of metals, and as a result, the carriage support member 31 is thermally deformed and becomes a pivot shaft. The pivot shaft 28 will be tilted. Therefore, in the present invention, as described above, the magnetic circuit 38 is fastened to a flat surface that does not affect the tilt using three screws at the positions shown in the figure. Furthermore, when current is supplied to the voice coil 30, the carriage member 25 is rotated at high speed in the radial direction of the magnetic disk 11 due to the electromagnetic force generated between the voice coil 30 and the magnetic flux forming section of the magnetic circuit section 38. accessed and located. At this time, since a current flows through the voice coil 30, the temperature of the voice coil 30 and the magnetic circuit section 38 increases extremely. Therefore, it is necessary to make the temperature distribution within the sealing body 13 uniform so that no thermal displacement occurs, and it is also necessary to prevent the above-mentioned thermal deformation due to the bonding of dissimilar metals from occurring. By increasing the heat dissipation effect according to the present invention, the sealed body 1
As a means for uniformizing the temperature distribution within the carriage support member 31, a magnetic circuit section 3 is provided on the flat surface of the carriage support member 31.
As shown in the figure, the part with the largest heat dissipation area in 8 is 3.
Fasten with real screws to prevent thermal deformation.
In addition, the magnetic circuit section 38 is configured to have a gap between the gate post-shaped side parts, and in order to further enhance the heat dissipation effect from the magnetic circuit section 38, as shown in FIG. A concave portion 300 having a curvature larger than the outer diameter of the plurality of magnetic disks 11 is provided in the portion, and a plurality of convex portions 300 have a curvature smaller than the curvature.
01 and configured so that the convex part 301 is inserted between the surfaces of the magnetic disk 11, the convex part 301 serves as a heat dissipation fin and is cooled by the wind speed or volume of the magnetic disk 11. . Therefore, the temperature distribution around the magnetic circuit section 38 is also made uniform, and thermal deformation due to extreme temperature rise does not occur. Therefore, the pivot shaft 28, which is a pivot shaft, is not tilted, and the off-track margin can be improved and the temperature distribution within the sealed body can be made uniform. Furthermore, by improving the heat dissipation effect, it has become possible to miniaturize and improve the performance of the magnetic circuit.

(E) Furthermore, a pair of highly rigid bearings 33 and 34 are inserted into the carriage member 25 at predetermined positions. These bearings 33 and 34 rotate on the pivot shaft 28, which is a rotation support shaft, but if the shape of the carriage support member 31 is a square shape like the conventional device, the rigidity is weak. In positioning using a voice coil motor that has a low natural frequency and performs servo control, a resonance phenomenon is likely to occur due to the coincidence of the natural frequency of these mechanical systems and the natural frequency of the servo head. This appears as vibrations in the servo head. This resonance phenomenon occurs due to the low rigidity of the spindle portion, the base member, and the carriage support member. As a means to reduce this head vibration,
The carriage support member 31 has a gatepost shape (cross-shaped shape) as shown in the figure to increase rigidity, and also has a plurality of convex portions 301 (the magnetic circuit portion 38 (similar to the part that obtains the heat dissipation effect), the rigidity can be increased and the natural frequency can be increased at the same time, and it can be set to a high vibration range that does not match the natural frequency of the servo head, eliminating the servo head vibration phenomenon. It became possible.

(F) Furthermore, in this embodiment, a recess 300 having the curvature larger than the outer diameter of the plurality of magnetic disks 11 is provided at the other end of the gatepost shape (cross-shaped shape) of the carriage support member 31. By providing this, it becomes possible to efficiently collect the airflow generated by the rotation of the magnetic disk 11 without any loss. Further, the magnetic head positioning mechanism 24 configured in this manner is fastened to the base member 10 forming the sealing body 13 as shown in FIG. The base member 10 has a rib structure to reduce weight and increase rigidity. Since the rib structure can increase the surface area for forming the sealing body 13, it is also useful for improving the heat dissipation effect within the sealing body 13. In order to further increase the rigidity of the base member 10, the end face of the base member 10 is further raised as shown in the drawing. Further, in order to form the sealing body 13, a cover 18 and a gasket 39 are provided.
has been fixed through. This cover 18 is also made of the same material as the base member 10 in order to avoid dissimilar metal bonding with the base member 10. As shown in FIG. 1, such a base member 10 has a base protrusion 302 ( The magnetic head positioning mechanism 24 and the base protrusion 302 are fastened together with a small gap 303 between the magnetic head positioning mechanism 24 and the base projection 302. Configure it so that With this configuration, part of the airflow due to the rotation of the magnetic disk 11 passes through the magnetic head 23 and enters the magnetic head positioning mechanism 24, but the gate pillar shape of the carriage support member 31 Most of the dust along the curvature of the portion 300 and the curvature of the base protrusion 302 is collected into an internal dust collection port 304 (collection structure not shown). Further, since a small gap 303 is provided between the magnetic head positioning mechanism 24 and the base protrusion 302, the gate-post-shaped recess 30 of the carriage support member 31
Since a very high air velocity flows along the curved surface of the base protrusion 302 and the curved surface of the base protrusion 302, the airflow that flows into the magnetic head positioning mechanism 24 from the small gap 303 is as follows. , the dust is completely blown out by the "mist blowing effect" without creating any air pockets, and the dust is removed from the dust collection port 30.
Leads to 4. For this purpose, new improvements in air circulation efficiency, uniformity of temperature distribution within the sealing body 13 of the head disk assembly, and improvement in cooling efficiency were achieved by simply making improvements to each member as described above. Since no parts are required, it has become possible to realize an inexpensive magnetic disk storage device having a highly reliable and high performance magnetic head positioning mechanism.

〔Effect of the invention〕

As described above, according to the present invention, the airflow generated by the rotation of the magnetic disk is utilized to seal the heat of the voice coil motor by the fins provided on the non-movable member facing the disk of the magnetic head positioning mechanism. It can be diffused into the sealed body to make the temperature inside the sealed body uniform.

[Brief explanation of drawings]

1 is a plan view showing an embodiment of a magnetic disk storage device according to the present invention, FIG. 2 is a side sectional view of FIG. 1, FIG. 3 is a perspective view of the magnetic head positioning mechanism of the present invention, and FIG. 5 and 5 are diagrams showing various parts of the positioning mechanism of FIG. 3. 24... Magnetic head positioning mechanism, 31... Carriage support member, 38... Magnetic circuit section, 300
...Concave portion with a large curvature, 301...Convex portion with a small curvature, 302...Base protrusion, 3
03...Small gap.

Claims (1)

[Claims] 1. A movable member that fixes a magnetic head to one end and moves the magnetic head to a predetermined position on the magnetic disk, a coil member attached to the other end of the movable member, and a motor together with the coil member. What is claimed is: 1. A magnetic disk storage device having a non-movable member including a magnetic circuit section constituting a magnetic circuit, characterized in that a portion of the non-movable member facing the magnetic disk is provided with a fin.