JPH06251531A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To provide a magnetic disk device capable of uniformalizing the fixing force acting on magnetic recording media in a circumferential direction and preventing the waving deformation of the magnetic recording media to be the cause for an output fluctuation. CONSTITUTION:This magnetic disk device 5as a motor 15 which is housed in a hermetic spacing 7 in a housing 2, the magnetic recording media 30a to 30c which are mounted coaxially on the outer periphery of a rotor 20 of the motor and are rotated integrally with the rotor and a fixing member 35 which is coaxially mounted across the magnetic recording media and the rotor and insert and fix the magnetic recording media between the member and the rotor. The device is provided with plural set screws 38 which are screwed into the rotor through plural points spaced in the circumferential direction of the fixing member and press the fixing member to the magnetic recording media. The fixing member is constituted of a member having high rigidity.

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 a storage device for portable electronic equipment such as a portable computer, and more particularly to a structure for fixing the magnetic recording medium to a motor.

[0002]

2. Description of the Related Art As a storage device of a laptop or book type portable computer, there is known a storage device employing a magnetic disk device having a storage capacity much higher than a floppy disk device and high-speed accessibility.

This type of magnetic disk device has a box-shaped housing, and the inside of this housing forms a clean airtight space which is shielded from the outside air. The airtight space accommodates various functional components such as a disk-shaped magnetic recording medium, a motor for rotating the magnetic recording medium, and a magnetic head for recording / reproducing data on / from the magnetic recording medium. .

The motor has a rotor that rotates integrally with the magnetic recording medium. This rotor is rotatably supported on the outer periphery of the motor shaft via a ball bearing. One end of the motor shaft is supported by the motor bracket in a cantilevered manner, and the motor bracket is screwed to the bottom surface of the housing.

The magnetic recording medium rotated by the motor has a fitting hole at the center of rotation, and the fitting hole is fitted to the outer periphery of the rotor so that the magnetic recording medium is supported coaxially with the motor. There is. And in the conventional magnetic disk device,
Since the motor shaft is supported by the housing in a cantilevered state as described above, the other end, which is the free end of the motor shaft,
The central portion of a disk-shaped fixing member having a spring property is coaxially attached via a screw, and the spring force of the fixing member is used to sandwich and fix the magnetic recording medium with the rotor. .

That is, the fixing member has an outer diameter larger than that of the rotor, and when the central portion of the fixing member is tightened with a screw, the outer peripheral portion of the fixing member is elastically attached to the upper surface of the magnetic recording medium. It is being pushed against. At this time, since the central portion of the fixing member is screwed to the motor shaft, the spring force applied to the contact portion with the magnetic recording medium, that is, the pressing force becomes uniform along the circumferential direction. It is possible to securely fix the rotor to the rotor without causing distortion.

By the way, since the conventional portable computer handles a smaller amount of information than a large-sized computer system, the storage capacity required for the magnetic disk device is also small, which is 2.5 to 40-130 megabytes.
Inch type magnetic disk devices were often used. However, recent improvements in the performance of portable computers are remarkable, and the performance required for magnetic disk devices tends to increase accordingly.

The first performance required is to increase the storage capacity. As is already known, the housing of the portable computer is designed to be compact in order to enhance portability, so the magnetic disk device can be easily installed in the compact housing to achieve a large capacity. Therefore, it is necessary to increase the recording density.

In order to realize the high recording density, it is required to suppress the vibration of the motor and the whirling of the magnetic recording medium based on the vibration. To meet this requirement,
It is effective to change the motor shaft of the motor from conventional cantilever support to both-end support.

[0010]

However, when both ends of the motor shaft are supported by the housing, the central portion of the fixing member for fixing the magnetic recording medium cannot be screwed to the other end surface of the motor shaft. Therefore, this fixing member
There is no choice but to fix it to the end surface of the rotor via screws at a plurality of locations spaced apart in the circumferential direction.

When the fixing member is fixed to the rotor by a plurality of screws in this way, the fixing force of the portion where the screws are present is the fixing force of the portion distant from the screws, specifically, the portion located between the screws. Therefore, the fixing force applied to the magnetic recording medium via the fixing member varies along the circumferential direction. Therefore, distortion may occur in the inner peripheral portion of the magnetic recording medium with which the fixing member is in contact, and the magnetic recording medium itself may be undulated and deformed when the magnetic recording medium is fixed.

Then, when the magnetic head levitates, the flying height fluctuates many times during one rotation of the magnetic recording medium, so that the followability of the magnetic head with respect to the magnetic recording medium deteriorates, and the reproduction output of the magnetic head. Will undesirably fluctuate.

The present invention has been made under such circumstances, and the fixing force applied to the magnetic recording medium can be equalized along the circumferential direction, and the waviness of the magnetic recording medium causing the output fluctuation. An object of the present invention is to provide a magnetic disk device that can prevent deformation.

Another object of the present invention is to provide a magnetic disk device capable of preventing the tightening tool (screw member) from loosening and maintaining the fixing force of the magnetic recording medium constant.

Still another aspect of the present invention is to provide a magnetic disk device capable of preventing the magnetic recording medium from being displaced from the rotation center of the motor and improving the positioning accuracy of the magnetic head on the magnetic recording medium. is there.

[0016]

In order to achieve the above object, a magnetic disk device according to a first aspect of the invention has a housing having an airtight space which is shielded from the outside air, and is housed in the airtight space of the housing. A motor having a rotor that rotates in the direction around the axis of the motor shaft, a magnetic recording medium that is coaxially mounted on the outer periphery of the rotor and that rotates integrally with the rotor, and between the magnetic recording medium and the rotor. A fixing member that is mounted coaxially over the magnetic recording medium and that fixes the magnetic recording medium by sandwiching it between the rotor and a plurality of positions that are spaced apart in the circumferential direction of the fixing member. A plurality of fasteners that are screwed into the rotor and press the fixing member against the magnetic recording medium are provided, and the fixing member is configured by a member having high rigidity.

According to another aspect of the magnetic disk device of the present invention, a housing having an airtight space that is shielded from the outside air is housed in the housing, and the magnetic disk device is housed in the airtight space of the housing and rotated in the axial direction of the motor shaft. A motor having a rotor, a magnetic recording medium that is coaxially mounted on the outer periphery of the rotor, is rotated integrally with the rotor, and is coaxially mounted across the magnetic recording medium and the rotor. A fixing member for sandwiching and fixing the magnetic recording medium between the rotor and the magnetic recording medium, and screwed into the rotor through a plurality of circumferentially-spaced portions of the fixing member to magnetically fix the fixing member. And a plurality of screw members that press the recording medium.

The fixing member is made of a material having high rigidity, and a spring washer for preventing the screw member from loosening is interposed between the fixing member and the screw member.

A third aspect of the present invention is characterized in that, in the first or second aspect, both ends of the motor shaft are supported by the housing.

According to a fourth aspect of the present invention, in the above-mentioned third aspect, the shaft length of the motor shaft is 15 mm or more.

Further, in the magnetic disk device according to a fifth aspect of the present invention, a housing having an airtight space which is shielded from the outside air inside is housed in the airtight space of the housing,
A motor having a rotor that is rotated around the axis of the motor shaft, a magnetic recording medium that is coaxially mounted on the outer periphery of the rotor, and that rotates integrally with the rotor, and between the magnetic recording medium and the rotor. A fixing member which is mounted coaxially over the fixing member and which fixes the magnetic recording medium by sandwiching the magnetic recording medium with the rotor, and the fixing member which penetrates through a plurality of positions spaced apart in the circumferential direction of the fixing member. A plurality of fasteners screwed into the rotor and pressing the fixing member against the magnetic recording medium.

The fixing member is made of a material having high rigidity, and the difference in the coefficient of thermal expansion between the fixing member for fixing the magnetic recording medium to the rotor and the parts including the fastener is 8 ×. 10 ^- is characterized in ⁶ / ° to C set below.

According to a sixth aspect of the present invention, there is provided a magnetic disk device comprising a housing having an airtight space which is shielded from the outside air, and a rotor which is housed in the airtight space of the housing and which is rotated in the axial direction of the motor shaft. A motor that has
The magnetic recording medium is coaxially mounted on the outer circumference of the rotor, is rotated integrally with the rotor, and extends over at least one magnetic recording medium on which servo sectors are preliminarily written, and between the magnetic recording medium and the rotor. And a coaxial fixing member for fixing the magnetic recording medium by sandwiching it between the rotor and the fixing member, and screwing into the rotor through a plurality of circumferentially spaced portions of the fixing member. A plurality of fasteners that press the fixing member against the magnetic recording medium, and float on the magnetic recording medium when the magnetic recording medium rotates.
It has a magnetic head for recording and reproducing data.

The fixing member is made of a material having high rigidity, and the fixing force applied to the magnetic recording medium via the fixing member is determined by the number of mounted magnetic recording media.
Is defined as m × 20 Kgf or more.

[0025]

According to the structure described in claim 1, since the fixing member for pressing the magnetic recording medium is made of a highly rigid member which is difficult to be deformed even when a force is applied from the outside, this fixing member. Although the fixing member is fixed to the rotor via a plurality of fasteners, the fixing member does not deform at the portion where the fastener is present, and the fixing force of this portion is far from the fastener. Can be prevented from exceeding the fixing force of. Therefore, the fixing force applied to the magnetic recording medium through the fixing member can be equalized in the circumferential direction, and the magnetic recording medium can be prevented from being distorted.

According to the structure described in claim 2, since the screw member is screwed into the rotor through the spring washer, the screw member is not loosened even when external impact or vibration is applied to the magnetic disk device. It can be prevented. Therefore, although the magnetic recording medium is made of a highly rigid member that cannot absorb shocks and vibrations, it is possible to prevent the fixing force for the magnetic recording medium from decreasing.

According to the third and fourth aspects of the invention, since both ends of the motor shaft are supported by the housing, the vibration of the motor shaft and the vibration in the frequency range not synchronized with the rotation speed of the motor are reduced. can do. For this reason, whirling of the magnetic recording medium can be prevented, which is convenient for increasing the recording density of the magnetic recording medium.

According to the fifth aspect of the present invention, the coefficient of thermal expansion of the components for fixing the magnetic recording medium to the rotor, such as the fixing member and the fastener, is substantially the same, so that the magnetic disk device Even if the heat of the motor is transferred to the fixing member during operation, it is possible to prevent the tightening tool from loosening. Therefore, the fixing force applied to the magnetic recording medium can be maintained constant, and the magnetic recording medium can be firmly fixed to the rotor.

According to the structure described in claim 6, since the fixing member is a member having high rigidity, the fixing force applied to the magnetic recording medium is set to a large value obtained by multiplying 20 Kgf by the number of mounted magnetic recording media. Even when a large shock or vibration is applied to the magnetic disk device from the outside, the coaxiality of the magnetic recording medium with respect to the rotation center of the motor can be sufficiently secured. Therefore, it is possible to prevent the servo sector written on the magnetic recording medium from being eccentric from the rotation center of the motor, and to reliably determine the magnetic head on the magnetic recording medium.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings applied to a 2.5-inch magnetic disk device used in a portable computer.

1 and 3 show a 2.5-inch type magnetic disk device 1. This magnetic disk device 1
Has a housing 2 made of metal. The housing 2 of this embodiment has a height of 19 mm, a width of 70 mm, and a length of 100.
It has a flat rectangular box shape of mm. The housing 2 is composed of a base plate 3 having an open top surface and a top cover 4 that covers the top opening of the base plate 3. The top cover 4 is fixed to the base plate 3 via a plurality of screws 5, and a packing 6 is interposed between the base plate 3 and the top cover 4. Therefore, the inside of the housing 2 is a clean airtight space 7 that is shielded from the outside air.

As shown in FIGS. 1 and 4, a motor mounting hole 8 is formed in the bottom wall 3a of the base plate 3.
A motor bracket 9 is attached to the motor mounting hole 8. The motor bracket 9 has a motor mounting hole 8
A disc-shaped body portion 10 fitted to the
And a flange portion 11 connected to the outer peripheral portion of 0. The flange portion 11 is fixed to the upper surface of the bottom wall 3a of the base plate 3 via screws 12. By this fixing, the motor bracket 9 is attached to the base plate 3 in a state where the motor mounting hole 8 is airtightly closed.

As shown in FIG. 2, an in-hub type motor 15 is supported on the motor bracket 9. The motor 15 is arranged in the airtight space 7 of the housing 2.
The motor 15 includes a motor shaft 16. The lower end of the motor shaft 16 is the body portion 1 of the motor bracket 9.
In addition to being fixed to 0, the upper end is abutted against the lower surface of the top cover 4 and is fixed via a screw 17. For this reason, the motor shaft 16 is supported by the housing 2 at both ends.
The axial length L of is set to 15 mm or more. And
If the motor shaft 16 is supported at both ends in this way, the vibration of the motor shaft 16 itself can be reduced, and the effect of reducing this vibration is particularly remarkable when the shaft length L of the motor shaft 16 is 15 mm or more. Become.

As shown in FIG. 2, a rotor 20 is rotatably supported on the outer periphery of the motor shaft 16 via first and second ball bearings 18 and 19. Ball bearing 1
Reference numerals 8 and 19 denote inner rings 1 fitted to the outer peripheral surface of the motor shaft 16.
8a, 19a and an outer ring 18 that rotates integrally with the rotor 20
b, 19b, and these inner rings 18a, 19a and outer ring 1
Ball-shaped rolling element 18 interposed between 8b and 19b
c, 19c. The ball bearings 18, 19 are
The ball spacers 18 and 19 are arranged apart from each other in the axial direction of the motor shaft 16, and a cylindrical spacer 21 is interposed between the outer rings 18b and 19b of the ball bearings 18 and 19. In the case of this embodiment, the first and second ball bearings 18, 19
The arrangement interval S is set to be 6 mm or more, and the longer the arrangement interval S of these ball bearings 18 and 19, the more effectively vibration of the rotor 20 with respect to the motor shaft 16 can be reduced.

The rotor 20 has a cylindrical rotor yoke 23.
And a cylindrical bearing support 24 arranged coaxially inside the rotor yoke 23. The rotor yoke 23 has a receiving portion 23 a that projects outward in the radial direction on the outer peripheral surface of the lower portion of the rotor yoke 23.
The upper end portions of 4 are integrally connected by a connecting wall 25. On the upper surface of the connecting wall 25, a ring-shaped guide wall 25a is coaxially projected. Bearing support 24
Are fitted to the outer circumferences of the outer rings 18b and 19b of the ball bearings 18 and 19, and by this fitting, the rotor 20 is rotatably supported outside the motor shaft 16. And
A magnet 26 that rotates integrally with the rotor yoke 23 is attached to the inner peripheral surface of the rotor yoke 23.

A stator 27 is arranged between the magnet 26 and the bearing support portion 24. The stator 27 is
The laminated core 28 and the coil 29 wound around the laminated core 28 are provided. The laminated core 28 is fixed to the body portion 10 of the motor bracket 9.

In such a motor 15, the rotor 20 is switched to 4000 by switching the energization of the coil 29 sequentially.
It is designed to rotate at a rotation speed of at least 4 / revolution / minute, preferably 4200 rotations / minute.

On the outer peripheral surface of the rotor yoke 23 of the rotor 20, three disk-shaped magnetic recording media 30a, 30b,
30c is fitted coaxially. These magnetic recording media 30a, 30b, 30c have a wall thickness T of about 0.9 mm, and the magnetic recording media 30a, 30b, 3
Circular fitting holes 31a, 31b, and 31c that are fitted to the outer circumference of the rotor 20 are concentrically opened at the center of 0c. Each magnetic recording medium 30a, 30b, 30c has a structure shown in FIG.
, A plurality of tracks T arranged concentrically
R0 to TRn are formed, and in the present embodiment, the number of tracks per inch is set to 3500 or more. Further, a plurality of servo sectors ST0 to STn for positioning control are written on each magnetic recording medium 30a, 30b, 30c at intervals in the circumferential direction. The servo sectors ST0 to STn include magnetic recording media 30a, 30b,
The servo sectors ST are arranged radially in 30c.
0 to STn extend so as to direct the rotation center X1 of the rotor 20. The rotation center X1 is located on the axis of the motor shaft 16. The magnetic recording media 30a, 30b, 30c as described above are provided with the spacer ring 32.
The magnetic recording media 30a, 30b, 30c, which are stacked on top of each other via a, 32b, have an arrangement interval I of 2.
It is set to 5 mm or less.

As shown in FIG. 2, a fixing member 35 is coaxially arranged on the upper surface of the rotor 20. The fixing member 35 is made of a highly rigid member such as stainless steel. The fixing member 35 is in the shape of a ring having a guide hole 36 through which the motor shaft 16 passes at the center thereof. The guide hole 36 is fitted on the outer periphery of the guide wall 25, and the fitting allows the rotor 20 and the fixing member 35 to be positioned.

The fixing member 35 is the connecting wall 25 of the rotor 20.
The support portion 35a located above and the pressing portion 35b which is continuous with the support portion 35a and contacts the upper surface of the uppermost magnetic recording medium 30a are integrally provided. As shown in FIG. 3 and FIG. 4, eight insertion holes 37 are opened in the support portion 35a. In the insertion hole 37, four fixing screws 38 as fastening tools are inserted every other one. These fixing screws 38
The insertion ends of the four screw holes 39 are formed in the connecting wall 25.
Is screwed into. By this screwing, the fixing member 3
The pressing portion 35b of No. 5 is pressed against the uppermost magnetic recording medium 30a.
Of the magnetic recording media 30a, 3
Center of rotation of 0b and 30c and spacer ring 32
It firmly inserts a and 32b. Therefore, the magnetic recording media 30a, 30b, 30c are integrated with the rotor 20 in a state where the intersections of the extension lines of the servo sectors ST0 to STn are located on the rotation center X1 of the rotor 20, and rotate together with the rotor 20. It is supposed to do.

In the case of this embodiment, the magnetic recording medium 3 is used.
The fixing force for 0a, 30b, 30c is set to 60 Kgf or more, which is larger than that of the conventional device. The value of this fixing force is empirically set to 20 Kgf from the reference value when tightening.
In this case, the number of mounted magnetic recording media 30a, 30b, 30c is m, that is, a value obtained by multiplying by 3 in the case of the present embodiment.

Further, in this embodiment, since the fixing member 35 is a member having high rigidity, the four fixing screws 38 are screwed into the screw holes 39 via the spring washers 40, respectively. As shown in FIG. 2, the spring washer 40 includes a fixing screw 38
It is compressed between the head portion 38a of the rotor and the connecting wall 25 of the rotor 20 to prevent the fixing screw 38 from loosening.

Further, in this embodiment, the magnetic recording medium 30 is used.
It has been attempted to reduce the difference in thermal expansion of the components required to fix the a, 30b, and 30c to the rotor 20. This component includes magnetic recording media 30a, 30b, 30c, spacer rings 32a, 32b, and a fixing member 3.
5, the fixing screw 38, and the spring washer 40, and the thermal expansion coefficients of these components are specifically determined as follows. The magnetic recording medium 30a, 30b, 30c: 9.9 × 10 - 6 / ° C spacer ring ^{32a, 32b: 17.3 × 10 -} 6 / ° C fixing member 35: 17.3 × 10 ^{- 6} / ° C fixed screw 38: 17.3 × 10 ^{- 6} / ° C spring washer 40: 15.8 × 10 ^{- 6} / ° C from this, the thermal expansion coefficient of the component to fix the magnetic recording medium 30a, 30b, and 30c to the rotor 20 Difference of 8 × 1
0 ^- is set to a value lower than ⁶ / ° C.

As shown in FIGS. 1 and 5, in the airtight space 7 of the housing 2, the magnetic recording media 30a, 30b, 30c.
A carriage assembly 45 is housed adjacent to the carriage assembly. The carriage assembly 45 includes a carriage 46. The carriage 46 has a cylindrical boss portion 47, and a pair of ball bearings 48 a,
A support shaft 49 is rotatably inserted through 48b. The lower end of the support shaft 49 is fixed to the base plate 3 via a screw 50, and the upper end of the support shaft 49 is fixed to the top cover 4 via another screw 51. Therefore, the carriage 46 is configured to rotate around the support shaft 49.

As shown in FIG. 1, the carriage 46 has four arm portions 52a, 52 connected to the outer peripheral surface of the boss portion 47.
It has b, 52c and 52d. Arm parts 52a, 5
2b, 52c, and 52d are arranged in parallel with each other with a gap in the axial direction of the boss portion 47, and these arm portions 5
Magnetic recording medium 30 between 2a, 52b, 52c and 52d
The outer peripheral portions of a, 30b, and 30c enter.

Each arm portion 52a, 52b, 52c, 52
A magnetic head 53 is supported at each of the tip ends of d. The magnetic head 53 includes magnetic recording media 30a, 30b,
The magnetic head 53 is for recording / reproducing data to / from the magnetic recording medium 30a, 30b, 30c.
Six pieces are provided with the mounting of three pieces of c.

As shown in FIGS. 3 and 5, each magnetic head 53 has a thin plate-shaped suspension 54. One end of the suspension 54 has arms 52a, 5
Caulked to the tips of 2b, 52c and 52d. At the other end of the suspension 54, the gimbal portion 55
Is integrally formed, and a magnetic head slider 56 is attached to the portion of the gimbal portion 55 facing the magnetic recording media 30a, 30b, 30c. The magnetic head slider 56 has a thickness of about 0.5 mm or less and a width of about 1.6 mm.

The magnetic head 53 is adapted to float by the air flow on the magnetic recording media 30a, 30b, 30c generated by the rotation of the magnetic recording media 30a, 30b, 30c. Thirty
As shown in FIG. 7, the flying height F of the magnetic head 53 determined by the distance between the magnetic head slider 56 and the magnetic head sliders b and 30c is 0.1 micron or less, preferably 0.08 to 0.09 micron. It is set.

As shown in FIGS. 5 and 6, the airtight space 7 of the housing 2 accommodates a voice coil motor 60 for rotating the carriage 46 about a support shaft 49 as a fulcrum.
The voice coil motor 60 includes a top yoke 61 and a bottom yoke 62. These yokes 61, 62
Are spaced apart in the thickness direction of the housing 2, and are supported by the bottom wall 3a of the base plate 3 via screws 63. Then, on the lower surface of the top yoke 61,
The magnet 64 is fixed.

A coil support portion 66 having a flat coil 65 is interposed between the yokes 61 and 62. The coil support portion 66 is integrally provided on the boss portion 47 of the carriage 46 so that the coil support portion 66 moves integrally with the carriage 46. In such a voice coil motor 60, by changing the magnitude and direction of the current supplied to the coil 65, the rotation angle and the rotation direction of the carriage 46 are changed by the interaction between the current and the magnet 64. It is like this. As a result, the magnetic head slider 56 causes the magnetic recording media 30a, 30b, 3
Positioning is performed with respect to desired tracks TR0 to TRn on 0c so that data can be written and read.

As shown in FIGS. 3 and 5, the first printed circuit board 68 is arranged in the airtight space 7 of the housing 2. The first printed circuit board 68 is screwed to the bottom wall 3 a of the base plate 3 via a board bracket 69. A large number of circuit components 70 forming a control circuit section are mounted on the printed circuit board 68, and the printed circuit board 68 includes the flexible printed board 7.
It is electrically connected to the motor 15, the magnetic head 53, and the voice coil coater 60 via 1.

Further, as shown in FIGS. 1 and 6, a second printed circuit board 75 is screwed to the lower surface of the housing 2. The second printed circuit board 75 is electrically connected to the first printed circuit board 68 via the connector 76, and the second printed circuit board 75 is
A relay connector 77 connected to a control unit (not shown) of the portable computer is provided. Therefore, the magnetic disk device 1 exchanges signals with the portable computer via the second printed circuit board 75.

In the magnetic disk device 1 having such a structure, the motor shaft 16 of the motor 15 for rotating the magnetic recording media 30a, 30b, 30c is fixed to the rotor 20 because both ends are supported by the housing 2. Of the magnetic recording media 30a, 30b, 30c that are stored, especially the motor 1
When 5 is rotating at a speed of 4200 rotations / minute, it is possible to reduce vibration of a frequency that is not synchronized with the rotation speed.

Therefore, the magnetic recording media 30a, 30b,
The whirling of 30c can be prevented, and the rotation center X of the motor 15
It is possible to reduce the concentricity of the magnetic recording media 30a, 30b, 30c with respect to 1 and thus the eccentricity of the servo sectors ST0 to STn on the magnetic recording media 30a, 30b, 30c, and to reduce the magnetic head 53 to the magnetic recording media 30a, 30b, 30b.
The desired tracks TR0 to TRn on 30c can be accurately positioned.

By the way, in this magnetic disk device 1,
Since both ends of the motor shaft 16 are supported by the housing 2, the central portion of the fixing member 35 for fixing the magnetic recording media 30a, 30b, 30c cannot be fixed to the upper end surface of the motor shaft 16. For this reason, the fixing member 35 has a ring shape having a guide hole 36 for avoiding the motor shaft 16 in the central portion, and the support portion 35 a connected to the guide hole 36.
Are fastened to the rotor 20 via four fixing screws 38.

In this case, in the above structure, the fixing member 35 is made of a highly rigid stainless material and has a rigidity such that it is difficult to be deformed only by applying an external force. Even if it is fixed to the rotor 20 via the fixing screws 38 at each of four positions spaced apart in the circumferential direction, the fixing member 35 is less likely to be deformed at the fixing screws 38. If the deformation of the fixing member 35 is small, the fixing force transmitted from the fixing member 35 to the magnetic recording media 30a, 30b, 30c at the portion where the fixing screw 38 exists and the fixing member 35 at the portion far from the fixing screw 38. There is no imbalance with the fixing force transmitted to the magnetic recording media 30a, 30b, 30c, and the fixing force due to the screwing of the fixing screw 38 causes the magnetic recording media 30a, 30b, It is transmitted to 30c.

Therefore, the fixing force applied to the magnetic recording media 30a, 30b, 30c through the fixing member 35 is equalized along the circumferential direction, so that these magnetic recording media 30
It is possible to prevent the inner peripheral portions of the a, 30b, and 30c from being distorted, and to suppress the waviness and deformation of the magnetic recording media 30a, 30b, and 30c, which causes the fluctuation of the reproduction output.

In addition, according to the above configuration, the fixing screw 38
Since the screw is screwed into the rotor 20 via the spring washer 40, it is possible to prevent the fixing screw 38 from loosening even when external impact or vibration is applied to the magnetic disk device 1.

Moreover, the magnetic recording media 30a, 30b, 3
A component for fixing 0c to the rotor 20, specifically,
Starting from these magnetic recording media 30a, 30b, 30c, the spacer rings 32a, 32b, the fixing member 35, the fixing screw 38, and the spring washer 40 are set to have substantially the same thermal expansion coefficient. × 10 ^{- 6} / ° C
Since there is only such a very small value, the heat of the motor 15 is applied to the magnetic recording medium 30 during operation of the magnetic disk device 1.
Even if it is transmitted to the fixed portions of a, 30b, and 30c, it is possible to prevent the fixing screw 38 from loosening due to thermal expansion.

As a result, the fixing force of the fixing screw 38 can be maintained constant even though the fixing member 35 is made of a highly rigid member that cannot absorb shocks and vibrations. Magnetic recording medium 30a, 30b, 30c
Can be firmly fixed to the rotor 20.

Further, in the magnetic disk device 1 having the above structure, the rigidity of the fixing member 35 is high, so that the magnetic recording medium 30 is
The fixing force to a, 30b, 30c is set to a value of 20 Kgf, which is a reference when tightening the magnetic recording medium 30a, 30c.
b, 30c It is set to a value obtained by multiplying the mounting number by 3, that is, 60 Kgf or more, and this fixing force is larger than the conventional one. Therefore, even if an external shock or vibration is applied to the magnetic disk device 1, the magnetic recording media 30a, 30b, 30c are prevented from being displaced from the rotation center X1 of the motor 15, and the coaxiality can be sufficiently ensured. . Therefore, it is possible to prevent the servo sectors SR0 to STn written on the magnetic recording media 30a, 30b, 30c from being eccentric from the rotation center X1 of the motor 15, and the magnetic recording media 30
The positioning accuracy of the magnetic head 53 on the a, 30b, and 30c can be improved.

In carrying out the present invention, the number of magnetic recording media to be mounted and the number of magnetic heads are not limited to those in the above embodiment, and for example, the number of magnetic recording media to be mounted is two. The number of magnetic heads may be four.

Of course, the material and shape of the fixing member and the number of fixing screws for fixing the fixing member to the rotor are not limited to those in the above embodiment.

[0064]

According to the structure described in claim 1, since the deformation of the fixing member at the portion corresponding to the tightening tool is prevented, the fixing force by the tightening tool is magnetic throughout the entire circumference of the fixing member. By being transmitted to the recording medium, the fixing force applied to the magnetic recording medium through this fixing member can be equalized along the circumferential direction. Therefore, it is possible to prevent distortion from occurring in the inner peripheral portion of the magnetic recording medium, and suppress waviness deformation of the magnetic recording medium that causes fluctuations in reproduction output.

According to the second aspect of the present invention, the fastener is screwed into the motor through the spring washer, so that the fastener is loosened even when external impact or vibration is applied to the magnetic disk device. Can be prevented. Therefore, even though the fixing member is made of a highly rigid member that does not absorb shocks and vibrations, the fixing force by the fastener can be maintained constant, and the magnetic recording medium can be applied to the rotor. Can be firmly fixed.

According to the third and fourth aspects, since the motor shaft is supported by the housing at both ends, whirling of the magnetic recording medium can be prevented, and the coaxiality of the magnetic recording medium with respect to the rotation center axis of the motor. As a result, the amount of eccentricity of the servo sector on the magnetic recording medium can be reduced. Therefore, the magnetic head can be accurately positioned on a desired track on the magnetic recording medium.

[0067] According to the configuration described in claim 5, the difference in thermal expansion coefficients of the parts for fixing the magnetic recording medium to the motor is, 8 × 10 ^{- 6} / ° negligible value as that C Therefore, even if the heat of the motor is transferred to the fixed portion of the magnetic recording medium during the operation of the magnetic disk device, it is possible to prevent the tightening tool from loosening due to thermal expansion. From this,
The fixing force by the fastener can be maintained constant, and the magnetic recording medium can be firmly fixed to the motor.

According to the structure described in claim 6, even when an external shock or vibration is applied to the magnetic disk device, the magnetic recording medium is prevented from being displaced from the rotation center of the motor, and the coaxiality is sufficiently ensured. can do. Therefore, it is possible to prevent the servo sector written on the magnetic recording medium from being eccentric from the rotation center axis of the motor, and it is possible to improve the positioning accuracy of the magnetic head on the magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a motor that rotates a magnetic recording medium.

FIG. 3 is an exploded perspective view of a magnetic disk device showing a state in which a top cover is separated.

FIG. 4 is an exploded perspective view showing a state in which a motor and a magnetic recording medium are incorporated in a base plate.

FIG. 5 is a plan view of the magnetic disk device with a top cover removed.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a schematic diagram showing a state in which a magnetic head is levitated from a magnetic recording medium.

FIG. 8 is a conceptual diagram showing tracks and servo sectors on a magnetic recording medium.

[Explanation of symbols]

2 ... Housing, 7 ... Airtight space, 1
5 ... motor, 16 ... motor shaft, 2
0 ... Rotor, 30a, 30b, 3
0c ... magnetic recording medium, 35 ... fixing member,
38 ... Tightening tool (fixing screw), 40 ... Spring washer,
53 ... Magnetic head.

Claims (6)

[Claims] 1. A housing having an airtight space that is shielded from the outside air, a motor that has a rotor that is housed in the airtight space of the housing and that rotates in the direction around the axis of the motor shaft, and a coaxial shaft on the outer circumference of the rotor. Magnetic recording medium that is mounted in a circular shape and is rotated integrally with the rotor, and is mounted coaxially across the magnetic recording medium and the rotor, and the magnetic recording medium is sandwiched between the rotor and the magnetic recording medium. A fixing member for inserting and fixing, and a plurality of fasteners that pass through a plurality of circumferentially spaced intervals of the fixing member and are screwed into the rotor, and press the fixing member against the magnetic recording medium, A magnetic disk device comprising the above-mentioned fixing member and a member having high rigidity. 2. A housing having an airtight space which is shielded from the outside air, a motor having a rotor which is housed in the airtight space of the housing and is rotated in the direction around the axis of the motor shaft, and coaxial with the outer circumference of the rotor. Magnetic recording medium that is mounted in a circular shape and is rotated integrally with the rotor, and is mounted coaxially across the magnetic recording medium and the rotor, and the magnetic recording medium is sandwiched between the rotor and the magnetic recording medium. A fixing member for inserting and fixing the fixing member, and a plurality of screw members which are screwed into the rotor by penetrating a plurality of positions spaced apart in the circumferential direction of the fixing member and pressing the fixing member against the magnetic recording medium. The magnetic disc is characterized in that the fixing member is formed of a member having high rigidity, and a spring washer for preventing loosening of the screw member is interposed between the fixing member and the screw member. Disk device. 3. In the description of claim 1 or 2,
The magnetic disk device according to claim 1, wherein both ends of a motor shaft of the motor are supported by the housing. 4. The magnetic disk drive according to claim 3, wherein the shaft length of the motor shaft is 15 mm or more. 5. A housing having an airtight space that is shielded from the outside air inside, a motor having a rotor housed in the airtight space of the housing and rotated in the direction around the axis of the motor shaft, and coaxial with the outer periphery of the rotor. Magnetic recording medium that is mounted in a circular shape and is rotated integrally with the rotor, and is mounted coaxially across the magnetic recording medium and the rotor, and the magnetic recording medium is sandwiched between the rotor and the magnetic recording medium. A fixing member for inserting and fixing, and a plurality of fasteners that pass through a plurality of circumferentially spaced intervals of the fixing member and are screwed into the rotor, and press the fixing member against the magnetic recording medium, And the difference in the coefficient of thermal expansion between the fixing member for fixing the magnetic recording medium to the rotor and the parts including the fastener is 8 × 10
-A magnetic disk device characterized by being set to ⁶ / ° C or less. 6. A housing having an airtight space that is shielded from the outside air inside, a motor having a rotor housed in the airtight space of the housing and rotated in the axial direction of the motor shaft, and coaxial with the outer circumference of the rotor. At least one magnetic recording medium in which servo sectors are preliminarily written, and is coaxially mounted across the magnetic recording medium and the rotor. A fixing member for sandwiching and fixing the magnetic recording medium between the rotor and the rotor, and screwing into the rotor by penetrating through a plurality of circumferentially spaced portions of the fixing member, A magnetic head provided with a plurality of fasteners that press against the magnetic recording medium, and a magnetic head that floats on the magnetic recording medium and records / reproduces data when the magnetic recording medium rotates. A disk apparatus, together constituting the fixing member at high rigidity member, the fixing force exerted on the magnetic recording medium through the fixing member,
A magnetic disk device characterized in that the number of mounted magnetic recording media is defined as m × 20 Kgf or more, where m is the number of mounted magnetic recording media.