JPH07130136A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To attain super high speed access by arranging a 1st shaft supporting plural disks and a 2nd shaft supporting a carriage so as to be almost parallel to one of two sides other than the shortest side of a casing. CONSTITUTION:The disks 2 are integrally mounted on the shaft 3 keeping specific spaces, and the shaft 3 is arranged almost in paralled to the longest side L3 of the casing 1. Plural projecting arms 12 to which heads 11 are respectively fixed at the tips, are provided on the carriage 10, and a pair of coil supporting parts 13 is provided on both ends at the opposite side of the arm 12, and a movable coil 9 is arranged on the supporting parts 13. The dimensions of the mobile coil 9 and a fixed magnet 8 in the direction of the longest side L3 are set longer than the shortest side L1 of the casing 1. Since the shaft 3 of the disk 2 and the carriage 10 are arranged so as to be parallel to the longest side L3 of the casing 1 in such a manner, the effective length of the coil 9 can be made longer, then a torque constant and a acceleration constant are increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device used as an external storage device such as a computer.

In recent years, the capacity of magnetic disk devices has been increasing as the areal recording density of recording media has increased. However, the access time is slowly growing due to the structure of the actuator, dimensional restrictions of the device, etc., and the average access time is currently about 8 ms as the upper limit. Therefore, it is desired to speed up the access time.

[0003]

2. Description of the Related Art A magnetic disk device includes a plurality of rotatably supported information recording media, a motor for integrally rotating the plurality of disks, and a plurality of heads for reading and writing information from and to the disks. It is configured to include an actuator and a housing that houses these actuators.

The actuator has a driving means composed of a fixed magnet and a movable coil provided so as to face the fixed magnet, and a plurality of projecting arms to which heads are respectively fixed at their tips, and an intermediate portion is rotatably supported. Along with
The movable coil is attached to the opposite side of the arm, and is composed of a carriage which is swung about the rotation axis by the driving means.

By the way, since the magnetic disk device may be built in a workstation, a personal computer or the like, its housing has a predetermined form factor in order to ensure compatibility in physical shape between different models. Often designed according to.

[0006] Here, the form factor means a dimensional standard established by some organization or the like or a dimensional standard customarily adopted by the industry (generally, it is often followed by a leading maker). Currently, 82.
6 mm x 146.1 mm x 203.2 mm (5.25 inch form factor), 41.3 mm x 101.6 m
m x 146.1 mm (3.5 inch form factor), and 25.4 mm x 73.0 mm x 101.6 m
m (2.5 inch form factor) and the like are known.

In the conventional magnetic disk device, by accommodating a disk having a diameter as large as possible with respect to the size of the housing, it is possible to increase the capacity.
The disk and the actuator were arranged so that their respective rotation axes were parallel to the shortest side of the housing. The shortest side of the housing is small (thin) as is clear from the above description of the form factor, and may accommodate a plurality of disks in order to accommodate a large capacity. It is provided inside a substantially cylindrical member that supports the disk.

[0008]

However, in the conventional disk device, since the rotation axes of the disk and the actuator are set parallel to the shortest side of the housing, the capacity can be increased by increasing the diameter of the disk. However, a large stroke for the head to move on the disk hinders the shortening of access time.

The motor for rotating the disk is
Since it is provided in the hub, the torque constant (torque generated per unit current) cannot be increased due to dimensional constraints, and the current at startup is large, making it difficult to design a high-speed rotation type motor.

Further, the wind loss, which is the loss due to the friction between the disc and the air due to the rotation of the disc, is generally proportional to the disc diameter and the number of revolutions of the disc. And the motor power consumption was increased.

When the movable coil of the actuator driving means is a vertical coil arranged in the rotational axis direction of the actuator, the effective coil length is limited by the dimension of the shortest side of the housing, and the acceleration constant (per unit current) The acceleration that occurs) was limited.

Due to these problems, conventionally,
A disk device having an average access time of 8 ms or less could not be realized. The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problems described above and speed up the access time.

In the specification of the present application, the torque constant and the acceleration constant are values defined as follows. That is, when the mass of the movable portion is m, the generated acceleration is α, the generated force is F, the magnetic flux density is B, the current is i, and the effective coil length is 1, the torque constant is defined by F / i = Bl. The acceleration constant is a value defined by α / i = Bl / m.

[0014]

In order to achieve the above object, the following constitution is provided. That is, a plurality of discs as information recording media rotatably supported by the first shaft, a spindle motor that integrally rotates the plurality of discs, and a plurality of heads that read and write information on the discs, respectively. A driving means including a fixed magnet and a movable coil provided so as to face the fixed magnet, and a plurality of protruding arms to which the heads are fixed, respectively, at the tip thereof, and the movable coil is provided on the opposite side of the arm. Installed,
In a disk device configured to house a carriage swingable about the second axis by the drive means in a housing having a shortest side and two sides longer than the shortest side,
The first axis and the second axis are arranged substantially parallel to one of two sides of the housing other than the shortest side.

[0015]

According to the present invention, the first shaft supporting the plurality of disks and the second shaft supporting the carriage are arranged substantially parallel to one of the two sides other than the shortest side of the housing. It is possible to accommodate a large number of small-diameter disks, the diameter of which is restricted by the shortest side of the housing, in the housing. Therefore,
The stroke of the head can be reduced without reducing the storage capacity.

In general, the access time is proportional to the 1/2 power of the stroke of the head and is proportional to the 1/2 power of the torque constant. Therefore, it becomes possible to perform an ultra-high speed access as compared with the conventional case.

Since the stroke of the head is small,
The movable coil of the drive means can be oscillated at the peak of the magnetic flux density of the magnetic circuit, which also makes it possible to increase the acceleration constant, which is the acceleration generated per unit current. Therefore, it is possible to obtain the acceleration of, and shorten the access time.

The effective coil length of the movable coil of the driving means (the length of the portion directly related to the generation of the driving force in relation to the fixed magnet) is conventionally restricted by the dimension of the shortest side of the housing. However, since this restriction is eliminated and the effective coil length can be made longer than in the conventional case, the acceleration constant can be improved, and this also makes it possible to shorten the access time.

Since the spindle motor does not have to stick to the in-hub type, the dimensional constraint is greatly reduced as compared with the conventional one, and the force generating portion R (the portion where the force is generated by the coil and the magnet of the spindle motor). It is possible to employ a large-sized motor having a large distance (distance from the output shaft), and therefore a torque constant can be increased.

Further, since the disk has a small diameter, the windage loss is significantly reduced, the load on the motor is reduced, and the rotational speed of the disk can be increased. Therefore, the rotation waiting time (time required for half rotation of the disk) to access the target data on the disk can be reduced,
The access time can be shortened.

As an example of a specific numerical value for the windage loss, the windage loss of a conventional one having an effective area (recordable area) of 18800 mm ² using two 3.5 inch disks. Is 2.16W, while 1.
Although 20 3-inch disks were used and the effective area was set to 18040 mm ² which was almost the same as the conventional one, the wind loss was 0.1
It is very small, 3 W, and the benefit of adopting the present invention is very large.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing the configuration of the first embodiment of the present invention. In the figure, reference numeral 1 denotes a housing, and the housing 1 has a shortest side (L1) of 41 mm and an intermediate side (L
2) is set to 110 mm and the longest side (L3) is set to 147 mm.

Reference numeral 2 is a 1.3-inch disk (area recording density is 300 Mb / in ² , storage capacity is 50 MB) as an information recording medium, and disk 2 is 1 GB.
20 sheets are provided to realize the storage capacity of. These discs 2 are integrally attached to a shaft 3 with a constant space therebetween, and both ends of the shaft 3 are rotatably supported by a subframe 5 via inner ring rotary bearings 4. The shaft 3 is arranged substantially parallel to the longest side L3 of the housing 1.

A spindle motor 6 is provided at one end of the shaft 3, and the output shaft of the spindle motor 6 is connected to the shaft 3. The spindle motor 6 is constructed by fixedly disposing a coil around the output shaft and disposing a magnet around the coil with a predetermined gap, and as shown in FIG. 1, it is provided outside the shaft 3. A large motor is used as compared with the conventional motor provided in the hub.

Reference numeral 7 denotes an actuator. The actuator 7 has a driving means composed of a fixed magnet 8 and a movable coil (shaft parallel type coil) 9 arranged to face the fixed magnet 8 with a predetermined gap, and a carriage 10. It consists of and.

As shown in FIG. 2A, the carriage 10 is provided with a plurality of projecting arms 12 to which heads 11 are fixed, respectively, as shown in FIG.
A pair of coil supporting portions 13 is provided at both ends on the opposite side of the above, and the movable coil 9 is installed on the coil supporting portions 13. A shaft 14 formed integrally with the carriage 10 is rotatably attached to the subframe 5 via an inner ring rotary bearing 15.

By appropriately energizing the movable coil 9 of the driving means, the carriage 13 is swung within a predetermined angle range, and the head 11 at the tip of the arm is positioned on a desired track of the disk 2.

As the movable coil, a shaft parallel type coil as shown in FIG. 3A or 3B is adopted, and the dimension of the movable coil 9 and the fixed magnet 8 in the longest side L3 direction is the same as that of the casing 1. It is set to be longer than the shortest side L1. In FIG. 3A or 3B, the dotted line indicates the swing (rotation) center of the carriage 10, that is, the central axis of the shaft 14.

Further, in FIG. 1, reference numeral 16 is a circuit board for controlling the operations of the spindle motor 6, the driving means (8, 9), the head 11 and the like, and other circuit boards. In addition,
In this embodiment, the magnetic circuit gap magnetic flux density of the driving means is 0.9 T, and the moment of inertia of the movable portion is 140 gc.
m ² , acceleration constant 60 G / A, head stroke 6.
3 mm, peak current is 1 A, and power consumption is 9 W. The disk rotation speed is 12000 rpm.

FIG. 4 shows a conventional wide stroke type in which the dimension in the direction orthogonal to the moving direction of the coil is the shortest side L1 of the housing.
It is a diagram for explaining the characteristics of the driving means shorter than
(A) is a developed view of the magnetic circuit, (B) is a Bg (gap magnetic flux density) distribution diagram, and (C) is a Bl distribution diagram obtained by integrating Bg with the effective coil length (l). In FIG. 1A, 1 is a housing, 8'is a fixed magnet, 9'is a movable coil, S is a stroke, and 1 is an effective coil length which is the length of an effective portion of the coil (shown by diagonal lines). is there.

FIG. 5 shows the conventional driving means in which the stroke S is narrowed to 1/4 so that the effective portion of the coil is located at the peak portion of Bg. (A) shows a magnetic circuit. Figure 2 (B) is Bg (gap magnetic flux density)
A distribution diagram, (C) is a Bl distribution diagram obtained by integrating Bg with the effective coil length (l). In FIG. 3A, 8 ″ is a fixed magnet, 9 ″ is a movable coil, S is a stroke, and 1 is an effective coil length which is the length of an effective portion of the coil (shown by diagonal lines).

FIG. 6 shows the drive means adopted in this embodiment. The stroke S is narrowed to 1/4 of that of the conventional drive means so that the effective portion of the coil is located at the peak portion of Bg. And the effective coil length l is made longer than the shortest side L1 of the housing 1.
(A) is a developed view of the magnetic circuit, (B) is a Bg (gap magnetic flux density) distribution diagram, and (C) is a Bl distribution diagram obtained by integrating Bg with the effective coil length (l). In FIG. 3A, 8 is a fixed magnet, 9 is a movable coil, S is a stroke, and 1 is an effective coil length which is the length of an effective portion of the coil (shown by diagonal lines).

As is apparent from FIGS. 4 to 6,
The stroke length S of FIG. 5 is shorter than that of the conventional stroke stroke of FIG. 4, and Bl is higher in the embodiment shown in FIG. 6 in which the effective coil length 1 is longer. There is.

As described above, the shaft 3 of the disk 2 and the shaft 14 of the actuator 7 (carriage 10).
Is arranged so as to be substantially parallel to the longest side L3 of the housing 1, and a 1.3-inch disk whose diameter of the disk 2 is smaller than the conventional 3.5-inch is used. The stroke S can be shortened, and since there is no restriction due to the dimension of the shortest side L1 of the housing 1 as in the conventional case, the effective coil length 1 of the movable coil 9 can be increased and Bl can be significantly improved. . Therefore, the torque constant and the acceleration constant can be increased, and the access time can be significantly improved.

The average access time in the configuration of this embodiment is 4 ms for cores and 1 m for fine (settling).
s, 5 ms in total, which was the upper limit of the conventional configuration 8
Ultra-high-speed access far exceeding ms has been realized.
Moreover, the average rotation waiting time is 2.5 ms, which is 1/3 of the one using the conventional 3.5-inch disk.
It is below.

Further, in the prior art, an in-hub structure (a structure in which the motor is provided inside the hub) is adopted for the motor for rotationally driving the disk because of dimensional constraints (constrained by the dimension of the shortest side of the housing). Therefore, the R of the torque generating portion of the motor is small and it is difficult to secure sufficient torque. Especially, in the high-speed rotation type motor, the current at the time of steady rotation becomes large, but by applying the present invention, Since the dimension of the disk in the direction of the rotation axis is large, the spindle motor 6 can be arranged outside the shaft 3 to which the disk 2 is fixed as in this embodiment, and therefore R of the torque generating portion of the spindle motor can be set. Can be made bigger, etc.
There are few design restrictions. With this, 12000 rpm
It is possible to use a highly efficient spindle motor that can sufficiently cope with the above high speed rotation.

Further, the shaft 3 is solid, and unlike the conventional hub (substantially cylindrical member), has high rigidity and can realize high speed rotation. Further, as for the bearing that rotatably supports the shaft, it is possible to use a bearing having high rigidity and low cost because the dimensional constraint is relaxed.

It is possible to secure an empty space by reducing the number of disks 2 or reducing the arrangement interval of the disks 2, and providing a cache memory and a circuit board for an interface in this empty space. Is also possible.

Next, in this embodiment, the dimensions of the movable coil 9 and the fixed magnet 8 in the direction of the longest side L3 of the housing 1 are longer than those of the conventional one, and the effective coil length 1 is long, as described above. Therefore, in the configuration shown in FIG. 2A in which the movable coil 9 is supported on the carriage 10 by the pair of coil support portions 13 with respect to the carriage 10, a problem occurs due to the vibration of the movable coil 9. There is no denying the possibility.

Therefore, as shown in FIG. 2B, the carriage 1 is wound with the movable coil 9 wound around the bobbin 17.
It is advisable to increase the number of coil supporting portions 13 of the carriage 10 that supports the movable coil 9 at 0.
With this configuration, the resonance frequency of the movable coil can be increased, and it is possible to reduce adverse effects on the positioning accuracy of the head.

Further, in this embodiment, 20 disks 2 each having a small diameter (1.3 inch) are provided, so that the storage capacity of two conventional 3.5 inch disks can be substantially matched. From the shaft 3 of the disc 2
It is conceivable that the mounting accuracy will be a problem. That is, generally, the disks 2 are arranged on the shaft 3 via the interval ring so as to have a predetermined interval sequentially from the one end side. However, as the number of disks increases, errors accumulate and the positional relationship with the head 11 of the actuator 7, for example. May cause problems.

In order to deal with such a problem, the structure shown in FIG. 7 can be used. That is, the positioning reference (protrusion) 18 is provided in the central portion of the shaft 3, and the disc 2
Are sequentially inserted from both ends of the shaft 3 through the spacing rings 19 and attached. By doing so, the accumulation of errors is reduced, and the above problems can be solved.

The positioning reference 18 can be provided at a portion other than the central portion, or a plurality of positioning references 18 can be provided by devising the structure of the shaft.

The carriage 10 of the actuator 7
Similarly, when the plurality of arms 12 forming a part of the shaft 7 are sequentially inserted into the shaft 14 via the spacing ring, the shaft 14 of the actuator 7
The same effect can be obtained by providing a similar positioning reference in the.

In the first embodiment, the shaft 3 of the disk 2 and the shaft 14 of the actuator 7 are also included.
Are arranged so as to be substantially parallel to the longest side L3 of the housing 1, but it goes without saying that they may be arranged so as to be parallel to the middle side L2 of the housing 1.

FIG. 8 is a partially cutaway perspective view showing the structure of the second embodiment of the present invention. The substantially same parts as those in the first embodiment are designated by the same reference numerals, and only different parts will be described.

That is, in this embodiment, two disk units each having 20 1.3-inch disks with a disk-to-disk pitch of 2.5 mm are arranged side by side in a size area based on the 3.5-inch form factor. There is.

Even if the thickness of the spindle motor is added by setting the pitch between the disks to 2.5 mm, it is 7
It fits in a length of 0 mm and is about half the dimension of the longest side of the 3.5 inch form factor, so that a disk device composed of two disk units can be constructed. With this configuration, it is possible to realize a storage capacity (2 GB) that is twice as large as that of the first embodiment. In the figure, reference numeral 20 is a cover, and in this second embodiment, the circuit board 16 is provided below the housing 1.

In addition to the first or second embodiment, although not shown, by applying the present invention,
Since a dimensional allowance can be provided in the housing, it is possible to further speed up the access time by devising a driving method such as providing two actuators and independently driving them.

In the first or second embodiment, the description has been given of the case where the 1.3-inch disk is used for the 3.5-inch form factor, but the present invention is not limited to this. Instead, for example, it can be configured as follows.

That is, a 1.8-inch disk is used for a 5.25-inch form factor (82.6 mm × 146.1 mm × 203.2 mm), or
2.5 inch form factor (25.4 mm x 73.
0 mm x 101.6 mm) at least 25.4
It can be configured to use discs with a diameter smaller than mm.

[0052]

Since the present invention is configured as described above in detail, it is possible to realize an access time that greatly exceeds the access time that has been conventionally limited. Further, there is an effect that the storage capacity can be increased and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a partially broken perspective view showing a configuration of a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a part of the actuator of the first embodiment of the present invention, in which (A) shows a general configuration and (B) shows a general configuration.
Indicates a configuration in which the influence of vibration is reduced.

FIG. 3 is a diagram showing an example of a movable coil adopted in the driving means of the first embodiment of the present invention.

4A and 4B are diagrams showing characteristics of a driving unit in the related art, where FIG. 4A is a development view of a magnetic circuit, and FIG. 4B is a Bg distribution diagram;
(C) is a Bl distribution chart.

FIG. 5 is a diagram showing the characteristics of a part of the driving means in the prior art that is modified, FIG. 5A being a development view of a magnetic circuit;
(B) is a Bg distribution chart, and (C) is a Bl distribution chart.

6A and 6B are diagrams showing characteristics of the driving means in the first embodiment of the present invention, FIG. 6A is a development view of a magnetic circuit, and FIG. 6B is Bg.
Distribution chart, (C) is a Bl distribution chart.

FIG. 7 is an enlarged cross-sectional view of the vicinity of the disc mounting portion in the first embodiment of the present invention.

FIG. 8 is a partially broken perspective view showing a configuration of a second embodiment of the present invention.

[Explanation of symbols]

 1 Case 2 Disc 3 Disc Shaft 4 Inner Ring Rotating Bearing 5 Subframe 6 Spindle Motor 7 Actuator 8 Fixed Magnet 9 Moving Coil 10 Carriage 11 Head 12 Arm 13 Coil Support 14 Actuator Shaft 15 Inner Ring Rotating Bearing 16 Circuit Board 17 Bobbin 18 Positioning reference (projection) 19 Spacing ring L1 Shortest side L2 Middle side L3 Longest side S Stroke l Effective coil length

Claims (5)

[Claims] 1. A plurality of disks (2) as information recording media rotatably supported by a first shaft (3), and a spindle motor (6) for integrally rotating the plurality of disks (2). ), A plurality of heads (11) for reading and writing information on the disk (2), a fixed magnet (8) and the fixed magnet, respectively.
(8) is provided with a driving means composed of a movable coil (9) and a plurality of protruding arms (12) to which the head (11) is fixed, respectively, at the tip of the driving means. The movable coil (9) is attached to the opposite side of the carriage (10) and is oscillated about the second shaft (14) by the driving means.
And a shortest side (L1) and two sides (L2,
A magnetic disk device configured to be housed in a housing (1) having L3), wherein the first shaft (3) and the second shaft (14) are
A magnetic disk device characterized in that it is arranged substantially parallel to one of two sides (L2, L3) other than the shortest side (L1) in (1). 2. The magnetic disk device according to claim 1, wherein the disk (2) is integrally attached to the first shaft (3), and the first shaft (3) rotates. The spindle motor (6) is movably supported by the first shaft.
A magnetic disk device, which is arranged outside (3). 3. The magnetic disk device according to claim 1, wherein the dimension of the shortest side (L1) and the other two sides (L2, L3) of the housing (1) is 82.6 mm × 146.1 mm. × 203.2 mm, 4
1.3 mm x 101.6 mm x 146.1 mm and 2
A magnetic disk device characterized by having a size of 5.4 mm × 73.0 mm × 101.6 mm. 4. The magnetic disk drive according to claim 2, wherein the first shaft (3) has a reference protrusion (18) for disk positioning at an intermediate portion of the first shaft (3). A magnetic disk device characterized in that 5. The magnetic disk drive according to claim 1, wherein the movable coil (9) of the drive means is fixed to the carriage (10) while being wound around a bobbin (17). Characteristic magnetic disk device.