JP2902463B2 - Magnetic disk drive - Google Patents

Description

The present invention relates to a magnetic disk drive.

[Problems to be solved by conventional technology and invention]

Generally, in a conventional magnetic disk drive, as shown in FIG. 4, a motor section c is provided between a base plate a and a top cover b. That is, the shaft d of the motor portion c is fixed to the base plate a and the top cover b, and the hub f is rotatably fitted to the shaft d via bearings e and e. Magnetic fluid seals h, h are attached to both ends of the inner peripheral surface g of the hub f. In addition, i is a rotor magnet attached to the inner peripheral surface g of the hub f, and j is a stator fitted to the shaft d.

Therefore, when the hub f rotates, the magnetic fluid k of the magnetic fluid seals h and h also rotates with the rotation of the hub f, and from inside the motor to the disk chamber m formed between the base plate a and the top cover b. The magnetic fluid k may be scattered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk drive in which a magnetic fluid of a magnetic fluid seal hardly scatters in a disk chamber.

[Means for solving the problem]

In order to achieve the above object, a magnetic disk drive according to the present invention includes a shaft fixed to a base plate forming a disk chamber and a top cover and housed between the base plate and the top cover; A magnetic disk device comprising: a hub rotatably fitted via a bearing; and a receiving member made of a magnetic material fitted to the end of the shaft in a loosely fitting manner. A magnetic fluid seal having a magnetic fluid received on an outer peripheral surface of the receiving member is provided on the base plate and the top cover.

(Operation)

The magnetic fluid seal will be provided on the fixed side that does not rotate, even if the hub rotates, the magnetic fluid seal does not rotate,
The magnetic fluid of the magnetic fluid seal is less likely to be scattered.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing examples.

FIG. 1 shows a magnetic disk drive according to the present invention, which comprises a base plate 1, a top cover 2, and a motor unit 3 provided between the base plate 1 and the top cover 2. It is.

Thus, the motor unit 3 includes a shaft 4, a hub 6 rotatably fitted to the shaft 4 via bearings 5, 5.
A stator 7 is externally fitted to the shaft 4, and a rotor magnet 9 is fixed to the inner peripheral surface 8 of the hub 6. The hub 6 includes a cylindrical main body 6a having a thick cover 2 side, and a ring-shaped spacer 6b fixed to the inner peripheral surface of the main body 6a on the base plate 1 side.
An outer flange 10 is provided on the outer peripheral surface on the base plate 1 side. A clamp member is provided on the outer peripheral surface of the hub 6.
Magnetic disks 12 are attached via 11.

Further, the shaft 4 is fixed to the base plate 1 and the top cover 2. That is, the shaft 4 has one end face 4a in contact with the base plate 1 and the other end face 4b in contact with the top cover 2, and is fixed to the base plate 1 with one end face 4a of the shaft 4 by a fixing member 13 such as a bolt attached to the base plate 1.
Is attached and the fixing device 13 attached to the top cover 2
Then, the other end surface 4b of the shaft 4 is attached to the top cover 2. 14 and 15 are holding pieces for holding the shaft 4. The stator 7 externally fitted to the shaft 4 has a stator core 7a on which a plurality of teeth are arranged along the circumferential direction.
And a coil 7b wound around the teeth of the stator core 7a
The stator core 7a is fixed to the shaft 4.

Thus, the receiving members 16, 16 made of a magnetic material are attached to the hub 6.
The base plate 1 and the top cover 2 are provided with magnetic fluid seals 17,17.

Here, as shown in FIG. 2, the receiving member 16 receives the magnetic fluid 19 of the magnetic fluid seal 17 on its outer peripheral surface 18, and the inner peripheral surface 20 is connected to the outer peripheral surface 4 c of the shaft 4. An adjacent cylindrical main body 16a, and a large-diameter portion 16b continuously provided from the base end of the main body 16a, one of the receiving members 16,
As shown in FIG. 1, the large diameter portion 16b is fixed to the inner peripheral surface of the spacer 6b of the hub 6, and the other receiving member 16 is
The large diameter portion 16b is fixed to the inner peripheral surface of the thick portion 21 of the main body 6a. That is, the receiving members 16, 16 are connected to the end portions 22,
The outer fitting 23 is loosely fitted.

As shown in FIG. 2, the magnetic fluid seal 17 includes an annular magnet 24, a pair of pole pieces 25, 25 for holding the annular magnet 24, an inner peripheral surface of the pole piece 25, 25 and a receiving member. 16
And the magnetic fluid 19 that is filled between the outer peripheral surface 18 and the magnetic fluid 19. That is, the base plate 1 is provided with a circular standing piece 26 into which the main body portion 16a of the one receiving member 16 is inserted,
A notch 27 is provided on the inner peripheral surface of the upright piece 26, and one magnetic fluid seal 17 is fitted and fixed to the notch 27,
The top cover 2 is provided with a circular upright piece 28 into which the main body 16a of the other receiving member 16 is inserted, and a notch 29 is provided on the inner peripheral surface of the upright piece 28, and the notch 29 Is fitted with the other magnetic fluid seal 17.

Between the upright piece 26 and the holding piece 14 and between the upright piece 28 and the holding piece 15, a plurality of circular through holes 30 and 31 are respectively provided at intervals in the circumferential direction (first 2 are shown in the figure). That is, the through holes 30, 31 are for injecting the magnetic fluids 19 of the magnetic fluid seals 17, 17,. These through holes 30, 31 also communicate the lower side of the base plate 1, the inside of the motor unit 3, and the upper side of the top cover 2. The magnetic fluid seals 17, 17 are provided with prevention covers 32, 32 for preventing fluid scattering.

Therefore, according to the magnetic disk drive configured as described above, the inside of the motor unit 3 includes the receiving member 16 and the through holes 30 and 3.
The disk chamber 33 is communicated with the outside of the disk chamber 33 via the first member 1, and the disk chamber 33 is isolated from the outside of the disk chamber 33 by the magnetic fluid seals 17. The disk chamber 33 is formed with a space between the base plate 1 and the top cover 2.

When the magnetic disk drive is driven and the hub 6 is rotated, the magnetic fluid seals 17, 17 do not rotate, and the receiving members 16, 16 rotate integrally with the hub 6, so that the magnetic fluid seal is rotated. The magnetic fluids 19, 17 are hardly scattered. In addition, vapors and mist of organic substances such as grease generated in the hub 6 are discharged out of the disk chamber 33 as shown by arrows. That is, the disk chamber 33 can always be kept clean. In addition, due to the flow of air from the inside of the motor unit 3 to the outside of the disk chamber 33, the internal heat also escapes to the outside of the disk chamber 33, and the temperature rise of the motor unit 3 is effectively prevented.

Next, FIG. 3 shows a modification of the standing piece 26, in which case,
The base plate 1 is a plate material, slits are provided in the plate 1 at predetermined intervals, and a predetermined range outside the slits is formed upright. Therefore, in this case, there is an advantage that the through-hole 30 is formed by forming the standing piece 26. If the top cover 2 is a plate, the upright pieces 28
Is preferably bent and formed in the same manner as the upright piece 26 shown in FIG.

In the embodiment shown in FIGS. 1 and 2, after the motor portion 3 is assembled between the base plate 1 and the top cover 2, the magnetic fluid 19 of the magnetic fluid seals 17, 17 is passed through the through hole 3.
The magnetic fluid 19 can be easily injected as a whole, and the magnetic fluid 19 can be easily injected without uneven injection, and can be replenished. Further, there is an advantage that leakage during injection does not occur in the disk chamber 33.

〔The invention's effect〕

Since the present invention is configured as described above, the following effects can be obtained.

Even when the magnetic disk drive is driven and the hub 6 is rotated, the magnetic fluid seal 17 itself does not rotate, and the magnetic fluid 19 of the magnetic fluid seal 17 hardly scatters from the holding position. Thus, the disk chamber 33 is not contaminated. In other words, if the magnetic fluid seal rotates together with the hub, the higher the speed, the more the magnetic fluid scatters, and it is not possible to rotate at high speed.
According to this device, even when the hub 6 is rotated at high speed, there is no scattering of the magnetic fluid. Therefore, this device is suitable for a device in which the hub 6 rotates at high speed.

[Brief description of the drawings]

1 is a sectional view of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part, and FIG. 3 is an enlarged sectional view of a main part of a modification. 4th
The figure is a sectional view of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Base plate, 2 ... Top cover, 4 ... Shaft, 5 ... Bearing, 6 ... Hub, 16 ... Receiving member, 17
…… magnetic fluid seal, 18 …… outer peripheral surface, 19 …… magnetic fluid,
22,23 ... End, 33 ... Disc room.

Claims (1)

(57) [Claims] A base plate for forming a disk chamber;
A shaft 4 fixed to the base plate 1 and the top cover 2 and fixed to the base cover 1 and the top cover 2, and a hub 6 rotatably fitted to the shaft 4 via a bearing 5.
In the magnetic disk drive, the receiving members 16 and 16 made of a magnetic material are loosely fitted to the ends 22 and 23 of the shaft 4 and fixed to the hub 6. Magnetic fluid received on outer peripheral surface 18 of 16
The magnetic fluid seal 17 having the
And a magnetic disk drive provided on the top cover 2.