JPS61270521A - Rolling bearing - Google Patents

Abstract

PURPOSE:To improve sealing performance in the captioned rolling bearing by providing a magnetic fluid sealing part between the inner periphery of an outer ring and the outer periphery of an inner ring so as to hold magnetic fluids through clamping a magnet between a plurality of magnetic yokes. CONSTITUTION:A magnetic fluid sealing part 7, which is formed between an outer ring 4 and an inner ring 5, is provided with a plurality of soft magnetic yokes 8a, 8b facing with each other at an interval and a permanent magnet 9 held between these yokes 8a, 8b. Gaps are formed between the inner periphery of the yokes 8a, 8b and the outer periphery of an inner ring 5 so that magnetic fluids 10a, 10b with lipophilic property is magnetically held between said gaps.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in sealing devices for rolling bearings.

[Conventional technology]

For example, as shown in FIG. 2, a room 1 for storing magnetic disk media of a hard magnetic disk device must be sealed and isolated to prevent dust from entering.

Conventionally, this is a rolling bearing that has been improved to prevent the intrusion of foreign matter and foreign matter from the outside.

For example, there is one described in Japanese Utility Model Publication No. 59-36735.

[Problem that the invention seeks to solve]

However, the reality is that if the bearing 3 of the shaft 2 connected to the spindle motor (not shown) is of the type described above, it cannot sufficiently prevent the grease within the bearing from scattering.

If grease enters the room 1, the function as a high-density recording medium device will be significantly reduced, which is undesirable.

Therefore, it is an object of the present invention to provide a rolling bearing having a magnetic fluid sealing function that absorbs dust generated from the bearing and has very good sealing performance with almost no torque loss.

[Means and effects for solving the problem] According to the present invention, a magnetic fluid is produced by sandwiching a magnet between a plurality of magnetic yokes and capturing a magnetic fluid between the inner circumference of the outer ring and the outer circumference of the inner ring. A rolling bearing characterized by having a fluid seal portion is obtained.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention.

4 indicates the outer ring of the bearing, and 5 indicates the inner ring. These are made of magnetic metal, and balls 6 are interposed between them. 7 is a magnetic fluid seal portion formed between the outer ring 4 and the inner ring 5. The magnetic fluid sealing section 7 includes a plurality of soft magnetic yokes 8a, 8b facing each other at intervals, and a permanent magnet 9 held between these yokes 8a, 8b. A gap is formed between the inner periphery of the yokes 8a, 8b and the outer moat of the inner ring 5, and the lipophilic magnetic fluids 10a, 10b are magnetically captured between these gaps. The magnetic circuit is permanent magnet 9 → yoke 8a → inner ring 5 → yoke 8b →
A closed magnetic path is taken for the permanent magnet 7a. An elastic ring-shaped non-magnetic material 11 such as Teflon or rubber is inserted between the magnetic fluid seal portion 7 and the inner periphery of the outer ring 4 in order to weaken the magnetic coupling and improve the sealing performance therebetween. . That is, the outer peripheral portion of the magnetic fluid seal portion 7 is connected to the outer ring 4 via the non-magnetic material 11.
attached to the inner circumference of the

Considering the purpose of the magnetic fluid pool section 7, the rolling ball 6
However, it is important to place it on the side of a clean room. Note that 5a is a spattered grease reservoir.

According to the above-described structure, the grease of the bearing is also absorbed by the magnetic fluid sealing portion 7, so that cleanliness is maintained and the function as a low-torque bearing is sufficiently maintained.

In the illustrated embodiment, the magnetic fluids 10a, LOb
It is possible to capture at two places (two stages), but it goes without saying that if there are more stages, the effect will be even greater.

Of course, the magnetic fluid seal portions 7 may be formed on both sides of the ball 6.

It is also preferable to provide sharp knife-like parts on the inner peripheral end faces of the yokes 8a and 8b, thereby concentrating the magnetic flux.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a rolling bearing that absorbs dust generated from the bearing and has a magnetic fluid sealing function with very good sealing performance and almost no torque loss.

[Brief explanation of drawings]

FIG. 1 is a sectional view of only a portion of an embodiment of the present invention. FIG. 2 is a schematic explanatory diagram of an applicable part of the present invention. 4... Outer ring, 5... Inner ring, 6... Ball, 7... Magnetic fluid seal portion, 8a, 8b... Soft magnetic yoke, 9
...Permanent magnet, IOa, IOb...Magnetic fluid, 11.
...Non-magnetic material. Figure 1 Figure 2

Claims (1)

[Claims] 1. A rolling bearing characterized in that a magnetic fluid seal portion is provided between the inner periphery of the outer ring and the outer periphery of the inner ring, the magnetic fluid seal being formed by sandwiching a magnet between a plurality of magnetic yokes to capture the magnetic fluid.