JPH0519610Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to bearings, and more particularly to bearings with magnetic fluid seals.

[Conventional technology and its problems]

2. Description of the Related Art Generally, small precision motors and the like use bearings equipped with magnetic fluid sealing devices that have minimal rotational resistance.

However, since grease is usually attached to the outer circumference of the bearing ball of a bearing, when the inner ring or outer ring rotates, this grease may mix with the magnetic fluid of the magnetic fluid sealing device. For example, there was a problem that sealing performance deteriorated.

Therefore, the purpose of this invention is to solve the above-mentioned conventional problems and provide a bearing that can exhibit sealing performance over a long period of time without mixing grease and magnetic fluid. do.

[Means for solving problems]

The bearing of the present invention includes an inner ring, an outer ring disposed radially outside the inner ring, and a ball interposed between the inner ring and the outer ring; , an annular magnet is disposed, and a magnetic fluid holding portion extending toward the inner ring and close to the outer circumferential surface or outer end surface of the magnet is provided at one end of the outer ring, and the holding portion in the outer ring A sealing plate for preventing lubricating grease from scattering is attached to the inner part of the disposed part, and a magnetic fluid is injected between the holding part and the outer peripheral surface or the outer end surface of the magnet, and the holding part The outer race, the seal plate, and the seal plate define an annular groove for receiving the grease flowing radially outwardly along the seal plate.

[Function] Since the seal plate is provided inside the magnetic fluid holding portion, the seal plate prevents the grease for lubricating the balls from scattering. Furthermore, since the magnetic fluid is injected between the magnet provided in the inner ring and the holding part that protrudes from the outer ring toward the inner ring, the magnetic fluid layer is located between the outer circumferential surface of the inner ring and the inner circumferential surface of the outer ring. Become. Furthermore, since the annular groove is defined by the holding part, the outer ring, and the seal plate, even if grease flows out through the inner ring and seal plate and flows radially outward along the outer surface of the seal plate, it will still flow out. The grease is contained in the annular groove.

〔Example〕

Hereinafter, the present invention will be explained in detail based on the drawings showing the illustrated embodiments.

FIG. 1 shows a bearing according to the present invention, which includes an inner ring 2 into which a shaft member 1 is fitted,
an outer ring 4 disposed on the radially outer side of the inner ring 2;
A ball 3 interposed between the inner ring 2 and the outer ring 4
A ring-shaped magnet 5 is disposed at one end 10 of the inner ring 2, and a ring-shaped magnet 5 is disposed at one end 11 of the outer ring 4 and extends toward the inner ring 2 and is close to the outer peripheral surface 6 of the magnet 5. A magnetic fluid holding section 12 is provided. A magnetic fluid A is provided between the holding portion 12 and the magnet 5.
is retained.

Thus, the magnet 5 has a magnetized portion 9 formed of N and S poles on its outer circumferential surface 6, and the magnetic fluid holding section 12 has a thin toroidal shape, and its inner circumferential surface 13 is attached to the magnet. The outer ring 4 is fixedly fitted inside the outer ring 4 so as to face the outer circumferential surface 6 of the outer ring 5 .

Therefore, as shown in FIG.
When the magnetic fluid A is injected into the gap 17 formed by the inner circumferential surface 13 of the magnetic fluid retaining portion 12, the magnetic fluid A is held in the gap 17. Further, a seal plate 14 for preventing the lubricating grease B from scattering is attached to a portion of the outer ring 4 inside the portion where the holding portion 12 is disposed. Specifically, the seal plate 14 is fixed to the inner peripheral surface 7 of the outer ring 4 between the magnet 5 and the ball 3.
Therefore, the holding part 12, the outer ring 4, and the seal plate 14
defines an annular groove 23 for accommodating the grease B flowing radially outward along the seal plate 14. A seal plate 15 prevents grease from scattering from the other end 18 of the bearing, and is fixed to the outer ring 4 in the illustrated example. 1
6 is a holding member that holds the ball 3.

When the outer ring 4 of this bearing rotates, if the grease B is attached to the inner circumferential surface 30 of the seal plate 14, centrifugal force in the direction of arrow X causes the inner circumferential surface 30 of the seal plate 14 and the inner ring 2 There is a risk that the particles may flow out from the gap 20 between the outer ring 4 and the outer circumferential surface 19 to the magnet 5 side and be blown to the inner circumferential surface 7 side of the outer ring 4. However, in this case, as shown in FIG. A gap 17 is formed inside the groove 23 and cannot move outward from the inner end surface 21 of the holding section 12, and holds the magnetic fluid A (this gap 17 is located at the inner end surface of the holding section 12). 21, it is assumed to be in an outward position.)
It doesn't get into that. In other words, even if the grease B flows out from the gap 20, the grease B does not mix with the magnetic fluid A.

Also, when the inner ring 2 rotates, the grease B adhering to the outer circumferential surface 19 of the inner ring 2 may flow out from the gap 20 and adhere to the inner circumferential surface 7 of the outer ring 4, but in this case as well, the above-mentioned As such, grease B and magnetic fluid A do not mix.

Next, FIG. 3 shows another embodiment of the bearing, in which the magnetic fluid holding portion 12 is provided close to the outer end surface 24 of the magnet 5. As shown in FIG.

That is, the magnetic fluid holding part 12 in this case is made of a flat ring body, and is fixed to one end surface 25 of the outer ring 4 so as to cover the outer end surface 24 of the magnet 5. In addition, the magnet 5 in this case has a magnetized portion 9 formed on the outer end surface 24 and an outer peripheral surface 6, as shown in FIG.
The side is set as the north pole, and the inner circumferential surface 26 side is set as the south pole.
Furthermore, the outer circumferential surface 6 of the magnet 5 and the inner circumferential surface 7 of the outer ring 4
The gap size C of the gap 27 between and is the gap 29 between the outer end surface 24 of the magnet 5 and the inner end surface 28 of the holding part 12.
is set larger than the gap dimension D of the gap 27.
The setting is such that the magnetic fluid A is not held in the magnetic fluid A. That is, since the gap 29 is smaller than the gap 27, the magnetic flux density in the gap 29 is large, and the magnetic fluid A is focused on the gap 29.

Therefore, in this embodiment, as in the above-mentioned embodiments, the magnetic fluid A is held closer to the inner diameter than the inner circumferential surface 7 of the outer ring 4, and furthermore,
It will be held at a position separated from the ball 3.

That is, in this embodiment as well, when the outer ring 4 rotates, the grease B is applied to the seal plate 14.
If the grease B adheres to the inner circumferential surface 30 of the outer ring 4, centrifugal force may cause the grease B to cross the gap 20 and adhere to the inner circumferential surface 7 of the outer ring 4 as shown by arrow X. As shown, the holding part 12, the outer ring 4,
Since the seal plate 14 defines an annular groove 23 for accommodating the grease B flowing radially outward along the seal plate 14, the grease B
Even if the grease B flows radially outward along the outer surface of the seal plate 14, the grease B thus flowed out is accommodated in the annular groove 23, and mixing of the grease B and the magnetic fluid A is reliably prevented.

Note that the present invention is not limited to the above-mentioned embodiments, and settings may be changed without departing from the gist of the present invention. For example, in the embodiments, the magnetic fluid holding portion 12
is composed of a separate member from the outer ring 4, but the outer ring 4
Alternatively, the magnet 5 and the magnetic fluid holding portion 12 may be provided on the other end 18 side.

[Effect of idea]

Since the present invention is constructed as described above, it produces the following effects.

Since the seal plate 14 prevents the grease B for lubricating the ball 3 from scattering, the magnetic fluid A and the grease B are separated by the seal plate 14, and mixing of the two is effectively prevented. .

In addition, the magnetic fluid layer is formed between the outer circumferential surface 19 of the inner ring 2 and the outer circumferential surface 19 of the outer ring 4.
Since the grease B and the like flowing along the outer circumferential surface 19 of the inner ring 2 and/or the inner circumferential surface 7 of the outer ring 4 can effectively mix with the magnetic fluid layer, Prevented.

Furthermore, even if the grease B flows out through the inner ring 2 and the seal plate 14 and flows radially outward along the outer surface of the seal plate 14, the grease B that flows out is accommodated in the annular groove 23, and the grease B Mixing of the magnetic fluid A and the magnetic fluid A is reliably prevented.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is an enlarged sectional view of the main part, FIG. 3 is a sectional view of the main part of another embodiment, and FIG. 4 is an enlarged sectional view of the main part. 2...Inner ring, 4...Outer ring, 5...Magnet, 6...
Outer circumferential surface, 7...inner circumferential surface, 10, 11... one end,
12...Magnetic fluid holding portion, 24...Outer end surface.

Claims (1)

[Claims for Utility Model Registration] A bearing comprising an inner ring 2, an outer ring 4 disposed radially outward of the inner ring 2, and balls 3 interposed between the inner ring 2 and the outer ring 4. An annular magnet 5 is disposed at one end 10 of the inner ring 2, and a ring-shaped magnet 5 is disposed at one end 11 of the outer ring 4 and extends toward the inner ring 2 and is attached to the outer peripheral surface 6 or outer end surface 24 of the magnet 5. A magnetic fluid holding part 12 is provided adjacent to the holding part 12 , and a sealing plate 14 for preventing lubricating grease B from scattering is attached to an inner side of the holding part 12 in the outer ring 4 . A magnetic fluid A is injected between the outer circumferential surface 6 or the outer end surface 24 of the magnet 5, and the holding portion 12, the outer ring 4, and the seal plate 14
is an annular groove 23 for accommodating the grease B flowing radially outward along the seal plate 14;
A bearing characterized by: