JPH0247294Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in a rolling bearing using magnetic fluid.

Conventionally, grease or lubricating oil has been used as a lubricant for rolling bearings, but bearings injected with these are not equipped with a sealing device or sealing structure when the bearing is in operation and when it is stopped after operation. Otherwise, it will flow out of the bearing during rotation.
Therefore, there is an inconvenience that the lubrication performance disappears within a short period of time.

In order to eliminate these drawbacks, we use magnetic fluid as a lubricant and appropriately magnetize the roller cage.
A rolling bearing has been proposed in which the magnetic fluid is captured by the magnetic field leaked by the retainer, and the magnetic lubricant can be held and captured within the bearing without the need for a special sealing device (for example, (See US Pat. No. 3,746,407).

FIG. 1 is a diagram showing an example of a rolling bearing using a conventional magnetic fluid as a lubricant. It is composed of inner and outer rings 1, 2, rolling elements 3, a retainer 4 made of appropriately magnetized permanent magnets provided so that the rolling elements do not come into contact with each other, and a magnetic fluid 5 using lubricating oil as a dispersion medium. There is. The magnetic fluid 5 is held and captured in the space where the rolling elements 3 are present by the leakage magnetic field of the permanent magnet of the retainer 4, and serves as a lubricant.

However, since the retainer 4 itself is a permanent magnet, contact with the rolling elements 3 causes mutual wear. For example, even if the cage 4 is made of a plastic magnet containing ferrite magnet powder, if the hard ferrite powder gets mixed in with the abrasion powder caused by this wear, it will affect not only the rolling elements 3 but also the outer inner ring 1. Wear is also accelerated in the outer ring 2 and the retainer 4 themselves, resulting in deterioration of the lubrication performance of the bearing.

In this way, if a permanent magnet is simply used as a roller retainer, contact between the rollers (rolling elements) and the permanent magnet will cause wear between them, and wear particles will further accelerate wear, causing damage to the bearing rings, etc. This has the disadvantage that the lubrication performance of the bearing is significantly deteriorated.

In order to reduce this drawback, the present invention covers the permanent magnet that properly magnetizes the cage with a non-magnetic material different from the permanent magnet, thereby reducing wear between the cage and the rolling elements and achieving high lubrication performance. The main purpose of this study is to propose a rolling bearing that uses magnetic fluid as a lubricant.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIGS. 2 and 3 are a cross-sectional view and a longitudinal cross-sectional view of the structure of a cage of a bearing developed in the direction of the inner ring, showing an example of the present invention. The structure of the bearing itself is the first
It is the same as the example shown, but the structure of the cage is different. That is, as shown in FIG. 2, the cage 40 is composed of permanent magnets 41 forming left and right base bodies, and a shell 42 made of, for example, plastic or phenol resin and covering the permanent magnets 41.

Therefore, the rolling elements 3 and the retainer 40 come into contact with each other, and wear particles are less likely to wear out the inner ring 1, the outer ring 2, and the rolling elements 3, which are the components of the outer bearing. Therefore, it is possible to realize a rolling bearing using a magnetic fluid having high lubricity as a lubricant.

FIG. 4 is a circumferential cross-sectional view showing another example of the bearing retainer of the present invention. In this embodiment, permanent magnets 53 are periodically embedded at regular intervals between the rolling elements 3 inside a support body 52 made of plastic or phenolic resin that constitutes the left and right retainers 50, 51. This is what I did.

Therefore, since the structure is substantially the same as that of Example 1, it is possible to realize a rolling bearing that exhibits the same effects and uses a magnetic fluid as a lubricant, which also has high lubricity.

Incidentally, the rolling elements of the bearing of the present invention are prevented from contacting each other by magnetic attraction between the cage and the rolling elements due to the buoyant force generated in the magnetic fluid against the non-magnetic fluid and the magnetic field of the permanent magnets generated in the cage. Since the effect will be further alleviated, it is expected that the bearing performance will further improve.

The bearing according to the present invention has a long life and is suitable for application, for example, to a bearing for a spindle of a magnetic disk, which is required to be maintenance-free, and its application is expected.

As described above, according to the present invention, in a rolling bearing consisting of a bearing ring consisting of an inner and an outer ring, rolling elements, a cage provided so that the rolling elements do not come into direct contact with each other, and a lubricant, the lubricant is a magnetic fluid. Since the surface of the cage is coated with a material different from the permanent magnet, which is suitably magnetized, the wear between the cage and the rolling elements constituting the rolling bearing is reduced. It becomes possible to provide a rolling bearing that uses a magnetic fluid as a lubricant that provides high lubrication performance.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional bearing of this type, Fig. 2 is a transverse cross-sectional view showing an example of the present invention, developed in the direction of the inner ring of the cage structure of the bearing, and Fig. 3 is a longitudinal cross-sectional view of the same; FIG. 4 is a cross-sectional view developed in the circumferential direction showing another example of the bearing retainer of the present invention. 1, 2... Inner/outer ring, 3... Rolling element, 5... Magnetic fluid, 40... Cage, 41... Permanent magnet,
42... Shell body made of plastics or phenolic resin, 50, 51... Left and right retainers, 52...
...Support, 53...Permanent magnet.

Claims (1)

[Scope of Claim for Utility Model Registration] A rolling bearing consisting of a raceway ring consisting of an inner and outer ring, rolling elements, a retainer provided so that the rolling elements do not touch each other directly, and a lubricant, wherein the lubricant is a magnetic fluid. . A rolling bearing, characterized in that the surface of the retainer covers the permanent magnets with a suitably magnetized material different from the permanent magnets.