JPH0126892Y2 - - Google Patents

Description

[Detailed Description of the Invention] (A) Technical Field of the Invention The present invention relates to a bearing mechanism, and particularly to a bearing mechanism of a spindle mechanism in a magnetic disk device with a sealed structure.

(B) Background of the technology A magnetic disk with a sealed structure is called a disk enclosure, and the enclosure houses a medium, a spindle mechanism that rotates the medium, a magnetic head that records and reproduces information on the medium, and a magnetic head. The actuator for seeking is housed within the housing and is isolated from the outside. This is because, in recent magnetic disk drives, the recording density of the magnetic disk medium has increased, and the flying height of the magnetic head has become extremely small (for example, 0.3 μm). However, head crash occurs when the magnetic head slides on the surface of the medium, so by isolating it from the outside,
Prevent dust from entering the housing.

For this reason, in recent magnetic disk devices, how to maintain a sealed state has become an important issue.

(C) Prior Art and Problems The spindle bearing mechanism of a magnetic disk device is constructed as shown in FIG. FIG. 1 is a side sectional view schematically showing a bearing mechanism of a conventional magnetic disk device.

A hub 4 is fixed to a shaft 10 which is rotatably held from the frame 1 via two sets of bearings 5, and a plurality of media 3 stacked at predetermined intervals by spacers 9 are attached to the outer periphery of the hub 4. has been done.
A rotor 11 to which a magnet is fixed is provided on the inner periphery of the hub 4, and a stator 12 having a coil formed thereon is provided on the frame 1 so as to face the rotor 11. Therefore, by energizing the coil of the stator 12, the hub 4 is rotated in the direction of arrow A around the shaft 10. This medium 3 is cover 2
It is covered by a hood and is designed to be isolated from the outside air. Further, the air inside the cover 2 is blown in the direction of arrow B by the rotation of the medium 3, and the air inside the cover 2 is blown in the direction of arrow B.
Along the top surface, the air flows in the vicinity of the shaft 10 in the direction of arrow C and is circulated, and filtered outside air is taken in through a breathing hole (not shown) and the pressure is raised higher than that of the outside air to prevent dust from flowing in from the outside air. This is taken into consideration.

Therefore, the bearing 5 in which the shaft 10 is held
A magnetic seal 6 is fixed by a metal fitting 7 so that the fixed portion of the shaft 10 also blocks outside air, and the magnetic fluid held by the magnetic flux of the magnetic seal 6 forms a film in the gap with the shaft 10, thereby blocking the air. .

To assemble the shaft 10, first insert the magnetic seal 6 of the shaft 10 to which the hub 4 is fixed, and then insert the bearing 5.
The inner ring of the frame 1 is press-fitted and the spring 13 is inserted between the upper and lower bearings to form a drive shaft assembly.Next, this drive shaft assembly is fitted into the bearing part of the frame 1, and the metal fitting 7 is attached to the frame. 1, the outer rings of the bearings 5 are pressed, and the magnets of the magnetic seals 6 are held together to attach the bearings.

However, such a configuration has the disadvantage that outside air flows through the contact surface 8 between the frame 1 and the metal fitting 7,
Furthermore, since the assembly is carried out as described above, it is not possible to inject the magnetic fluid into the magnetic seal 6 after assembly, so the injection of magnetic fluid is performed before inserting it into the shaft 10, so that the proper amount of magnetic fluid can be used to ensure magnetic properties. It is unclear whether a fluid film is formed around the outer circumference of the shaft 10. Therefore, if the amount of injection is small, a film will not be formed and there will be a problem that outside air will flow into the cover 2, and if the amount of injection is too large, there will be a problem that it will scatter and adhere to other equipment.

The present applicant has previously proposed a bearing mechanism for the purpose of eliminating such drawbacks in Utility Application No. 57-201051, which will be explained with reference to FIG. 2. In FIG. 2, a is a side sectional view, and b is a detailed view of the magnetic seal.

One of the bearings 5 held by the shaft 10 has a bearing 15 fixed to it so that a magnetic seal 6 is attached by a member 13,
The rest of the configuration is the same as in FIG. 1. bearing 1
The outer ring of 5 and the magnetic seal 6 are connected by a member 13 made of a non-magnetic material, and fixation to the frame 1 can be achieved by providing a groove on the outer periphery of the member 13 and inserting an O-ring 14. This is what I did.

The bearing 15 has a ball 15A as shown in b.
The outer ring 15B that clamps the member 13 is provided with a protruding surface so that the member 13 can be firmly fixed, and the member 13 is fixed to the magnetic seal 6 by this protruding surface, while the inner ring 15C forms the magnetic seal 6. The inner peripheral ends of a ring 6B fixed to both sides of the magnet 6A are extended so as to face each other. This inner circle 1
The gap shown by arrow D between 5C and ring 6B is filled with magnetic fluid.

With this configuration, the bearing 15 can be press-fitted into the shaft 10 during assembly, and
Since the magnetic seal 6 is fixed, the injection of the magnetic fluid and the formation of the coating can be confirmed, and it is possible to prevent assembly without the coating being formed, as in the conventional case. Furthermore, the contact surface 8 for fixing the magnetic seal 6 as in the conventional case is eliminated, and outside air no longer flows in.

Generally, the shaft 10 may be made of a material such as SUS, and in this case, the outer periphery of the shaft 10 must be formed of at least a magnetic material at the portion facing the ring 6B provided with the magnetic seal 6. There are rings, etc. However, the inner circle 15
Since C is provided, this is not necessary.

Further, by locking bearing seals 15A on both sides of the ball 15A, leakage of lubricating oil can be prevented.

However, according to this invention, the O-ring 14 is used to tightly fit the drive shaft assembly to the inner circumferential side of the frame 1, which makes the structure complicated and makes it difficult to fit the drive shaft assembly into the frame 1. Another disadvantage was that it required a large amount of force and took time to assemble the spindle mechanism.

(D) Purpose of the invention The purpose of the invention is to enable the drive shaft assembly to be brought into close contact with the inner circumferential side of the frame 1 with a simple structure, and to make it easy to fit the drive shaft assembly into the frame 1. There is a particular thing.

(E) Structure of the device The purpose of this device is to provide a bearing that holds a drive shaft, a magnetic seal that is attached to the bearing and has a magnetic fluid that blocks a gap in the direction of the drive shaft, and an outer ring of the bearing that connects the A drive shaft assembly comprising a mutually connected non-magnetic member provided between a fixed portion of a magnetic seal, and an elastic seal having pleat-like protrusions provided on the outer periphery of the non-magnetic member; This is achieved by providing a bearing mechanism comprising a frame into which the shaft assembly is fitted, and characterized in that the fold-like protrusions of the elastic seal are in close contact with the inner periphery of the frame.

(F) Embodiment of the invention Hereinafter, an embodiment of the invention will be explained in detail with reference to the drawings. FIG. 3 is a diagram showing the structure of the drive shaft assembly and frame 1, and the same parts as in FIGS. 1 and 2 are designated by the same numbers. 3a differs from FIG. 2 in that an elastic sealing material 16 is used instead of the O-ring 14. This elastic sealing material 16 has pleat-like protrusions 16a, as shown in the cross-sectional view of FIG. 4a. A top view of this elastic sealing material 16 is shown in FIG. 4c. Elastic sealing material 1
The radius a, the length b, and the thickness t of the projection 6 are appropriately determined depending on the force when the drive shaft assembly is fitted into the frame 1 and the pressure resistance of the elastic material. That is, since the elastic sealing material 16 is fixed to the member 13 and the pleats 16a must be in close contact with the frame 1, the length b, thickness t, and elasticity of the pleats 16a depend on the hardness of the material of the elastic material. Determine the radius a of the sealing material 16.

As shown in Figure 3b, there is a leakage route y for bearing grease and air flowing in from the outside.
This also allows the drive shaft assembly to be easily fitted into the frame 1 with little force. Note that the leakage route x shown in FIG. 3b can be easily blocked by fixing the magnetic seal 6B to the member 13 with an adhesive or the like.

When the hardness of the elastic sealant 16 is small, the fourth
As shown in FIG. b, two fold-like protrusions 16b may be provided to deal with this problem.

(G) Effects of the Invention As explained above, according to one embodiment of the present invention, the drive shaft assembly and the frame are configured to be in contact with each other through the elastic sealing material, so that the drive shaft assembly can be easily removed. It can be fitted into the frame, making it easy to assemble the device.

[Brief explanation of drawings]

Fig. 1 is a side sectional view schematically showing a bearing mechanism of a conventional magnetic disk device, Fig. 2 is a side sectional view of the bearing mechanism of a conventional magnetic disk device, b is a detailed view of the bearing, Fig. 3, FIG. 4 is a diagram showing an embodiment of the bearing mechanism according to the present invention. In the figure, 1 is a frame, 2 is a cover, and 3 is a frame.
is a medium, 4 is a hub, 5 and 15 are bearings, 6 is a magnetic seal, 7 is a metal fitting, 8 is a contact surface, 9 is a spacer, 10 is a shaft, 11 is a rotor, 12 is a stator,
13 is a member, 14 is an O-ring, and 16 is an elastic sealing material.

Claims (1)

[Scope of utility model registration request] A bearing that holds a drive shaft, a magnetic seal that is attached to the bearing and has a magnetic fluid that blocks a gap in the direction of the drive shaft, and is provided between an outer ring of the bearing and a fixed part of the magnetic seal to connect each other. a drive shaft assembly constituted by a non-magnetic member, an elastic seal having fold-like protrusions provided on the outer periphery of the non-magnetic member, and a frame into which the drive shaft assembly is fitted; A bearing mechanism characterized in that a pleated projection of a seal and an inner periphery of the frame are arranged in close contact with each other.