JPS63224090A - magnetic disk device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk drive, and more particularly to the structure of a base plate and a spindle motor section of a magnetic disk drive.

[Conventional technology]

A conventional magnetic disk device, as shown in FIG.
A bald head 22 is fixed to one end of the shaft 21, a plurality of magnetic disks 25 are attached to the hub 22 by a disk clamp plate 25 via a disk spacer 24, and a cup-shaped rotor yoke 26 is fixed to the other end of the shaft 21. , a rotor magnet 27 is provided on the inner side of the rotor yoke 26.
is fixed to the rotor magnet 27, and a stator core 29 is disposed on the inner peripheral side of the rotor magnet 27 with a gap in between.
The stator coil 28 is divided into multiple phases and is arranged in a stator core 29Fi housing 32, and the housing 32 includes a bearing 55 that supports the shaft 21 and a dustproof seal that prevents dust from entering the magnetic disk 23 side. 3
4 is arranged, the housing 32 is fixed to the base plate 30 with screws, etc., and the base plate 30 has a cover 3 to seal the space where the magnetic disk 23 exists from outside air.
1 is arranged and a circuit board 5shz is taken out on the other side. To assemble the magnetic disk device as shown in FIG.
3 are sequentially mounted on the hub 22, and the disk clamp plate 25 is screwed to the hub 22.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, the weir of the spindle motor unit requires many man-hours and a large number of parts to install, which increases the cost of the device and hinders miniaturization. This change caused the joint between the spindle motor and the base plate to break down, causing a thermal off-track between the information recording track of the magnetic disk and the magnetic head for reproducing information, significantly reducing the reliability of the magnetic disk drive.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a highly reliable magnetic disk drive that is easy to assemble in a shed.

[Means for solving problems]

A magnetic disk device of the present invention is a magnetic disk device having at least one magnetic disk, a spindle motor for rotating the magnetic disk, and a base plate on which the spindle motor is disposed. is molded integrally with the base plate, and the spindle motor is of an inner rotor type.

[Effect]

According to the above structure of the present invention, the number of parts and man-hours required for fastening the spindle motor to the base plate is reduced, and by adopting the inner rotor type, the process of fixing the spindle motor to the shaft and the process of fixing the stator part to the base plate are reduced. The fixing process can be separated in random order, and the motor part is easy to assemble and parts can be easily replaced.

〔Example〕

FIG. 1 is a dynamic view of the main parts of a magnetic disk drive according to an embodiment of the present invention, in which a hub 2 is fixed to one end of a shaft 1, and a plurality of magnetic disks 3 are connected to the disks via a disk bender 4. It is attached to the hub 2 by a ramp plate 5, and a cup-shaped rotor yoke 6 is fixed to the other end of the shaft 21. An a-ta magnet 7 is disposed on the outer surface side of the rotor yoke 6, and the outer circumferential side of the rotor magnet 7 A stator core 9 is arranged with a gap in between, a stator coil 8 is wound around the stator core 9, and a rotor section composed of a rotor yoke 6 and a rotor magnet 7 is connected to a stator section composed of a stator core 9 and a stator coil 8. It is located on the inner circumferential side of the rotor and is an inner rotor type. The space in which the magnetic disk 3 exists forms a sealed container surrounded by a base plate 10 and a cover 11, and the base plate 10 is provided with a stator core 9, a bearing 13, and a dustproof seal 14b, in particular a bearing that rotatably supports the shaft 1. 13 is usually a ball bearing, and when fixing the outer ring of the ball bearing to the base plate 10, the base plate 1 is used to make the coefficient of thermal expansion of the ball bearing and the fixed part approximately the same.
When molding 0 (usually aluminum die-cast) K sleeve 12
(usually made of bearing steel or stainless steel) is insert-molded to prevent the support portion of the shaft 1 from falling due to changes in the thermal environment. A circuit board 15 is attached to the base plate 100 on the opposite side of the cover 11 for recording and reproducing information and controlling the magnetic disk device.

Therefore, as is clear from the embodiment shown in Fig. 1, the number of man-hours and parts for installing the spindle motor are reduced, and the use of an integrated base plate reduces distortion due to changes in the thermal environment of the fastening section, thereby reducing thermal off-track. . However, by insert-molding and arranging the sleeve on the base plate, the thermal strain experienced by the bearing is further reduced, and off-track caused by tilting of the shaft can be almost eliminated. One of the purposes of the present invention is to reduce the size of the magnetic disk device.For example, a magnetic disk device larger than a 5.25-inch magnetic disk device has more space and is equipped with a built-in nozzle. A spindle motor is used and motor space is not much of an issue, but
Inner rotor type spindle motors are particularly effective in saving space as magnetic disks become smaller in diameter, such as in 3.5-inch magnetic disk drives, making it difficult to use a spindle motor with a built-in hub. This has a large space-saving effect and increases the mounting space on the base plate side of one circuit board, making it possible to make the magnetic disk device intelligent despite its small size of 15 inches.

〔Effect of the invention〕

As described above, according to the present invention, by adopting a magnetic disk device structure in which an inner rotor type spindle motor is mounted on an integrated base plate, it is possible to create a magnetic disk device that is small, easy to assemble, and highly reliable. Furthermore, by providing the sleeve on the bearing of the spindle motor, thermal off-track is reduced and the reliability of the magnetic disk drive is further improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of a magnetic disk device of the present invention. FIG. 2 is a sectional view of a main part of a conventional magnetic disk device. 3... Magnetic disk 6... Rotor yoke 7... Curved rotor magnet 8... Stator coil 9... Q... Stator core 10... Base plate 12. ...Meeting/Sleeve 13...Bearing and above Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Mogami and 1 other person r・St Stator Core Jshiq, Stator Core Fig. 1

Claims (1)

[Scope of Claims] 1) A magnetic disk drive including at least one magnetic disk, a spindle motor for rotating the magnetic disk, and a base plate on which the spindle motor is disposed, in which a bearing for the spindle motor is disposed. 1. A magnetic disk drive characterized in that a housing portion is integrally formed with a base plate, and the spindle motor is of an inner rotor type. 2) The magnetic disk device according to claim 1, wherein a cylindrical sleeve having substantially the same coefficient of thermal expansion as the bearing is inserted into the base plate of the housing portion.