JPS59227077A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To cause no capacitive disadvantage, no increase of the number of parts, nor complication of an assembly, etc., and to reduce a position shift of a magnetic head by placing a base in the center part of a device, and placing a magnet of a voice coil motor VCM, a carriages, a motor assembly, etc. in the upper and lower completely symmetrical type, on the base. CONSTITUTION:A VCM magnet 2 is fixed in the upper and lower completely symmetrical type to an opening part made on a base 1. A carriage 4 is connected to a coil 3 going in and out to and from a magnet 2, placed in the opening part so that the upper and lower parts become a complete symmetrical type, and the base 1 is inserted through the center part of a magnetic head. Also, a spindle motor assembly 10 of a direct driving system for rotating a disk 5 is fixed in the upper and lower complete symmetrical type to the base 1, and a spindle shaft 11 projects upper and lower. Two flanges 12 are attached to the shaft 11, and the disk 5 is incorporated. Accordingly, the base 1 is inserted through between a servo-surface 9 of the disk 5 and a data surface 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magnetic disk drive, and more particularly to a mounting structure for a voice coil motor, a carriage, and a spindle motor assembly to a base.

[Technical background of the invention and its problems]

FIG. 1 is a diagram showing an example of a conventional magnetic disk device. A magnet 2 of a voice coil motor (VCM) is fixed on a base 1, and a carriage 4 is connected to a coil 3 that goes in and out of the magnet 2. This carriage 4 is placed on a base 1 so as to be movable, and also includes a plurality of data heads 6 for reading and writing data onto a disk 5 and a servo head 7 for reading positional information written on the servo disk surface. It is equipped with. These data head 6 and servo head 7 move together with the carriage 4, which moves by the driving force F generated by the coil 3 of the VCM. At this time, since the center of gravity q1 of the disk assembly, the center of gravity G2 of the carriage, the point of application of the VCM center of gravity G3 and the driving force F are above the neutral axis XX of the base 1, the data head 6,
As the servo hend door moves, the base 1 is slightly curved as shown in FIG. Further, the curvature of the base 1 is also caused by thermal expansion caused by a temperature difference between the upper surface side and the lower surface side of the base l. Such curvature of the base 1 causes misalignment of each head as shown in Fig. 2, where ε is the misalignment between the data head 6 at the top and the servo head 7 below It shows the amount.

In addition to the above-mentioned causes, misalignment of the magnetic head also occurs due to the following causes. In other words, the device is constructed using multiple types of materials from the viewpoint of durability and performance.
Due to the difference in linear expansion coefficient of each material, temperature changes inside the device cause tilting of the spindle shaft, carriage, etc. that rotate the disk, which causes the positional deviation of the magnetic head.

As a conventional technique for eliminating such misalignment of the magnetic head, there is a method in which the disk assembly and the carriage are supported in a symmetrical supporting structure. However, this method has other drawbacks such as an increased number of parts, complicated assembly, and increased costs.

FIG. 3 shows another conventional method for eliminating misalignment of a magnetic head. This method has a structure in which the servo head 7, which was at the lowest position in FIG. 1, is moved to an intermediate position as shown in the figure.

With this structure, even if the positional deviation of the magnetic head as shown in Fig. 2 occurs, the amount of positional deviation between the servo head 7 and the data head 6 above and below it will be as shown in Fig. 1. This can be reduced to 1/2 compared to a structure with a similar structure. However, if a data hept 6 (indicated by reference numeral 8 in FIG. 3) is attached to the back of the servo head 7 for reading and writing on the disk surface, noise from the servo head 7 will be generated when writing data to the data head, causing a seek error. The disadvantage is that the disk surface 8 cannot be used as a data surface.Therefore, the disk surface 8 facing the servo surface 9 cannot be used, resulting in the disadvantage that the capacity of the device is reduced.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above drawbacks, an object of the present invention is to provide a magnetic disk device that reduces misalignment of a magnetic head without reducing capacity, increasing the number of parts, or complicating assembly.

[Summary of the invention]

The present invention has a vertically symmetrical structure of the device so that the center of gravity of the spindle motor assembly, carriage, and VCM and the point of application of the carriage driving force are aligned with the neutral axis of the base, thereby reducing the positional deviation of the head caused by the curvature of the base. By positioning the servo surface in the middle of the disk, the amount of head misalignment caused by tilting of the spindle shaft and carriage due to temperature changes can be halved. The above object is achieved by adopting a structure in which a stand is interposed so that all disk surfaces can be utilized.

[Embodiments of the invention]

An embodiment of the magnetic disk device of the present invention will be described below with reference to the drawings, using the same reference numerals for the same parts as those of the conventional example.

FIG. 4 is a configuration diagram showing an embodiment of the magnetic disk device of the present invention, and FIG. 5 is a perspective view thereof. A base 1 of the magnetic disk device is located at the center of the device, and a VCM magnet 2 is fixed vertically and completely symmetrically to an opening formed in the base 1. The carriage 4 is connected to a coil 3 that goes in and out of the magnet 2, and the carriage 4 is also arranged in the opening so that the top and bottom are completely symmetrical, and the magnetic head mounted on the carriage 4 is based on the center part. The stand 1 is inserted. Furthermore, a disk 5 is mounted on the base 1.
A direct drive type spindle motor assembly 10 for rotating the motor is fixed in a vertically perfectly symmetrical manner, and a spindle shaft 11 protrudes vertically. Two flanges 12 are attached to this spindle shaft 11,
A disk 5 is assembled into these flanges 12.

Therefore, the base 1 is connected to the servo surface 9 and the data surface 8 of the disk 5.
In addition, the servo head 7 mounted on the carriage 4 is placed in the middle of the head group.

According to this embodiment, the spindle motor assembly 10 and the magnet 2 of the carriage 4.70M are vertically and completely symmetrically arranged with respect to the base 1, and the center of gravity G1 of the disk rotation system is
, the center of gravity of the carriage G2, the center of gravity of the VCM magnet G3, and the point of application of the force F that drives the carriage 4 are all placed on the neutral axis X-X of the base 1, so that the neutral axis X-XK
The carriage 4
The curvature of the base 1 caused by the movement of the servo head 5 and the temperature difference between the top and bottom of the base 5 can be reduced to almost zero without increasing the number of parts and complicating the assembly. is located at the middle position of the magnetic head group, so even if the position of the magnetic head is shifted due to the inclination of the spindle shaft 11 or carriage 2 due to the difference in the i-expansion coefficient of each component material due to temperature changes within the device, The amount of displacement can be halved compared to the amount of displacement when the servo head 7 is brought to the lowest (or highest) position of the disk 5.

Moreover, since the base 1 is interposed between the servo surface 9 and the data surface 8, the write current of the data head 6 on the data surface 8 does not ride on the servo head 7, and no seek error occurs. , the amount of positional deviation can be halved without reducing the disk capacity. Therefore,
The amount of positional deviation of the entire magnetic head can be reduced without causing any disadvantages in terms of capacity, increase in the number of parts, or complication of assembly.

〔Effect of the invention〕

As described above (according to the magnetic disk device of the present invention,
A base is placed in the center of the device, and the VCM magnet, carriage, motor assembly, etc. are arranged vertically and completely symmetrically on the base to drive the VCM center of gravity, the carriage center of gravity, the center of gravity of the disk rotation system, and the carriage. By placing the point of application of the force on the neutral axis of the base, it is possible to significantly reduce the misalignment of the magnetic head without causing any disadvantages in terms of capacity, increase in the number of parts, or complication of assembly. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional magnetic disk device, and FIG. 2 is a block diagram showing an example of a disk device in which the misaligned state of a magnetic head is detected. Equality system, 5 years old 4 years old 4 (fan i raft Wσ)
. 1...-base, 2... magnet, 4... carriage, 5... disk, 6... data head, 7...
・Servo head, 8...Data side, 9...Servo side, 10...Spindle motor assembly agent Patent attorney Noriyuki Chika Fumoto (and 1 other person)

Claims (1)

[Claims] (Li) A base placed across the center of the device, a voice coil motor, a carriage on which a magnetic head is mounted, and a spindle motor assembly are arranged completely symmetrically on both sides of the base. A magnetic disk device characterized in that the center of gravity of the spindle motor assembly, carriage, and voice coil motor, and the point of application of the carriage driving force by the voice coil motor are aligned with the neutral axis of the base. (2) Among the plurality of disks rotated by the spindle motor, a servo surface is arranged in the center of the device, and the base is interposed between this servo surface and a data surface facing thereto. A magnetic disk device according to claim 1, characterized in that: