JPS63125824A - Rolling bearing - Google Patents

Abstract

PURPOSE:To improve lubricating property by forming a solid lubricant layer on at least one frictional surface of a bearing constituting part. CONSTITUTION:A plurality of rollers (balls) 3 are interposed rollably between inner and outer rings 2, 1. The rollers 3 are rotatably held by a corrugated punched holder 4. The base of an annular seal 5 utilizing magnetic fluid is fixedly fitted in one annular shoulder portion 1b of the outer ring 1. Solid lubricant layers 7, 8 are formed on the surface (track surface) of a circumferential groove 2a for guiding the roller on the inner ring 2 and the surface (track surface) of a circumferential groove 1a for guiding the roller on the outer ring 1. These layers are constituted from thin layers of molybdenum bisulfide, tungsten bisulfide, silver, etc. By these layers are given satisfactory sliding property to the rollers.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a rolling bearing, such as a ball bearing or a roller bearing, in which rolling elements (balls, rollers, etc.) are interposed between an outer ring and an inner ring so as to be able to freely roll. In particular, equipment and equipment that require high cleanliness,
Alternatively, the present invention relates to a rolling bearing that supports a rotating body in equipment and devices used in a vacuum or in a highly clean atmosphere such as a clean room (for example, an X-ray generator or a vacuum evaporation device).

<Prior art> In a rolling bearing, the bearing components (outer ring, inner ring, rolling element, or a cage for holding the rolling element, if the bearing has a cage that holds the rolling element, A lubricant is absolutely necessary to prevent wear and vibration of parts (including cages).

However, for rolling bearings in devices and devices that require high cleanliness or that are used in a highly clean atmosphere, leakage of the lubricant to the outside must be avoided at all costs.

The following two examples have been proposed as conventional rolling bearings that take this measure.

(1) One is proposed in Japanese Patent Laid-Open Publication No. 1801/1989 and Japanese Patent Laid-Open No. 57014/1982.

From the perspective of preventing lubricant leakage, this conventional example uses solid lubricants (soft metals such as silver Ag, lead PB, molybdenum disulfide MO) instead of using ordinary oil or grease as lubricant.
A soft non-metal such as No. 32) is used as a lubricant.

Solid lubricants have a significantly lower possibility of leaking to the outside of the bearing than greases that contain relatively large amounts of volatile components.

■ In this case, countermeasures were taken from a different perspective than the conventional example.
There are rolling bearings that use low-volatile grease as a lubricant and are configured to prevent the grease from leaking with a magnetic fluid seal. That is, an annular seal plate is attached to the annular opening between the outer ring and the inner ring with a slight gap left between the outer ring and the inner ring, and one of the image parts facing the gap is attached. One is made of a ferromagnetic material, the other is made of a permanent magnet, and a magnetic fluid is interposed between the ferromagnetic material and the permanent magnet.

In the case of this conventional example, the magnetic fluid is strongly held in the gap by the magnetic field formed between the permanent magnet and the ferromagnetic material, so that the grease is prevented from leaking to the outside.

<Problems to be Solved by the Invention> However, these conventional examples each have the following problems.

In the case of the conventional example (2), even if sufficient solid lubricant is used, the bearing components (outer ring,
Wear of the inner ring, rolling elements or cage cannot be avoided. Therefore, there is a possibility that abrasion powder generated by the abrasion leaks to the outside from the annular opening between the outer ring and the inner ring. Although there are some devices in which an annular seal is provided in the annular opening, the annular seal is a normal seal and has a gap, so leakage of abrasion powder is inevitable.

Furthermore, in the case of the conventional example (2), a low-volatility grease is used, but it is inevitable that this grease will be mixed into the magnetic fluid. When grease is mixed into the magnetic fluid, the concentration of the magnetic fluid decreases, and the pressure resistance of the magnetic fluid portion decreases. That is, there is a pressure difference between the inside and outside of the rolling bearing, and the internal pressure is usually higher where the rolling elements rotating at high speed are present. This pressure difference may cause volatile components of the grease to leak through the magnetic fluid with reduced pressure resistance.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide high lubricity and to reliably prevent leakage of lubricant.

Means for Solving the Problems> In order to achieve the above object, the present invention has the following configuration.

That is, the rolling bearing of the present invention is a rolling bearing in which a rolling element is rotatably interposed between an outer ring and an inner ring, in which at least one annular opening of both annular openings between the outer ring and the inner ring is provided. is closed by an annular seal using a magnetic fluid, and at least one of the plurality of bearing components including the outer ring, the inner ring, and the rolling elements receives friction as the rolling elements roll. A solid lubricant layer is formed on each friction surface.

In this configuration, the bearing components that undergo friction as the rolling elements roll include the outer ring, inner ring, and rolling elements, as well as the cage in the case of a rolling bearing that has a cage.

<Effect> The effects of the configuration of the present invention are as follows.

In other words, the friction surface of any one of the bearing components (including the outer ring, inner ring, rolling elements, or cage in the case of a bearing having a cage) that undergoes friction as the rolling elements roll. Since a solid lubricant layer is formed on the bearing, the rolling bearing has high lubricity. This is because some of the solid lubricant peeled off due to rolling is transferred to the friction surfaces of other bearing components.

Further, even if wear particles are mixed into the magnetic fluid, since the wear particles are solid, the concentration of the magnetic fluid does not decrease as in the case where grease is mixed. Therefore, a decrease in pressure resistance of the annular seal using magnetic fluid is prevented.

In this way, the annular opening between the outer ring and the inner ring is reliably closed by the annular seal that uses magnetic fluid, so even if wear particles are generated, it is reliably prevented from leaking to the outside. be done.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view of essential parts according to an embodiment of the present invention.

In Fig. 1, l is an outer ring, 1a is a rolling element guide circumferential groove formed on the inner circumferential surface of the outer ring 1, 2 is an inner ring concentrically inserted into the outer ring 1, and 2a is on the outer circumferential surface of the inner ring 2. This is a circumferential groove for a rolling element guide formed. A plurality of rolling elements (balls) 3 are fitted into the circumferential groove 1a of the outer ring 1 and the circumferential groove 2a of the inner ring 2.
is rotatably interposed between the outer ring 1 and the inner ring 2.

Reference numeral 4 denotes a corrugated punched retainer that rotatably holds a plurality of rolling elements 3 at predetermined intervals in the circumferential direction.

At the annular openings on both sides between the outer ring 1 and the inner ring 2, annular steps 1b and lc are formed on the inner peripheral surface of the outer ring 1, and the inner ring 2
An annular step portion 2b and a circumferential groove 2C are formed on the outer peripheral surface of.

A base portion of an annular seal 5 using magnetic fluid is fitted and fixed to one annular stepped portion 1b of the outer ring 1.

This annular seal 5 includes a seal body 5a made of an elastic material such as rubber, a reinforcing plate 5b integrally fixed to the inner surface of the seal body 5a, and a permanent magnet 5C fitted and fixed to the free end of the seal body 5a. It consists of A small annular gap is formed between the permanent magnet 5C and the annular stepped portion 2b of the inner ring 2, and this gap is filled with a magnetic fluid 5d over the entire circumference. Since the bearing steel constituting the inner ring 2 is a ferromagnetic material, a magnetic circuit is formed between the permanent magnet 5C and the annular stepped portion 2b, and the liquid 5d in this portion is strongly held.

A labyrinth seal 6 is provided on the other annular stepped portion 1c of the outer ring 1.
The base of the is fitted and fixed. This labyrinth seal 6
The seal body 6a is composed of a seal body 6a made of an elastic material such as rubber, a reinforcing plate 6b integrally fixed to the inner surface of the seal body 6a, and a lip 6c formed at the free end of the seal body 6a.

The lip 6c forms a small annular gap in the circumferential groove 2c of the inner ring 2, and the gap has a bent shape in the illustrated cross section. The bending of this gap ensures sealing performance based on the labyrinth effect.

The annular seal 5 using magnetic fluid is placed on the highly clean atmosphere side, and the labyrinth seal 6 is placed on the normal atmosphere side.

In this embodiment, in a rolling bearing having an annular seal 5 using a magnetic fluid in one annular opening, the surface (raceway surface) of the rolling element guide circumferential groove 1a in the outer ring 1 is
Solid lubricant layers 7 and 8 are formed on the surface (raceway surface) of the rolling element guide circumferential groove 2a in the inner ring 2. These solid lubricant layers 7 and 8 are made of molybdenum disulfide Mo5
It is composed of a thin layer of tungsten disulfide WS2, imAg, etc.

As described above, the rolling bearing of this embodiment has the annular seal 5 using magnetic fluid as a seal on the highly clean atmosphere side, and the solid lubricant layer 7 formed in the rolling element guide circumferential grooves 1a and 2a as a lubricant. I have .8.

When the rolling elements 3 roll along the rolling element guide circumferential grooves 1a and 2a due to the rotation of the inner ring 2 or outer ring l, the rolling elements 3 are smoothly moved by the solid lubricant layers 7.8 in the circumferential grooves 1a and 2a. It has excellent lubricity and rolls very smoothly with little resistance.

Note that the solid lubricant from which a part of the solid lubricant layer 7.8 has peeled off adheres to the surface of the rolling elements 3 and the inner surface 4a of the cage 4, so that the slipperiness of the rolling elements 3 is improved despite the peeling off. The goodness remains the same.

Outer ring 1. due to use over time. Inner circle 2. It is inevitable that the rolling elements 3 or the cage 4 will wear out. The abrasion powder generated by the abrasion is prevented from leaking to the outside by the labyrinth seal 6 into the normal atmosphere where high cleanliness is not required.

Although some wear powder leaks from the labyrinth seal 6, it is not a big problem because the leaked light is in a normal atmosphere that does not require high cleanliness.

Regarding the highly clean atmosphere side, even if wear particles are mixed into the magnetic fluid 5d, the concentration of the magnetic fluid 5d does not decrease, so that the pressure resistance of the annular seal 5 using the magnetic fluid 5d is maintained well. Therefore, leakage of abrasion powder to the outside can be reliably prevented.

As a result of the above, high lubricity and pressure resistance can be maintained over a long period of time. In particular, when this rolling bearing is used in equipment or equipment that requires high cleanliness, as it has a high ability to prevent wear debris from leaking, it will maintain the smooth operation of the equipment or equipment as expected. Furthermore, when the rolling bearing is installed in equipment or equipment used in a vacuum or highly clean atmosphere, there is no fear of contaminating the vacuum or highly clean atmosphere.

In addition, the following can be mentioned as another example which added a change to this example.

(i) A solid lubricant layer 7 is formed only in the circumferential groove 1a of the outer ring 1.

(1)) Contrary to the above, the solid lubricant layer 8 is formed only in the circumferential groove 2a of the inner ring 2.

(iii) Outer ring 1. The solid lubricant layer 7.8 on the circumference rtlIla and 2a of the inner ring 2 is eliminated, and instead a solid lubricant layer is formed on the surface of the rolling element 3, or the solid lubricant layer is formed on the inner surface 4a of the cage 4. What was formed.

(1v) Solid lubrication on any two, three, or all of the circumferential groove 1a of the outer ring 1, the circumferential groove 2a of the inner ring 2, the surface of the rolling elements 3, and the inner surface 4a of the cage 4. Formed with a layer of agent.

(v) Labyrinth seal 6 at one annular opening is eliminated, and both annular openings are closed with an annular seal 5 using magnetic fluid 5d.

Next, as an example of the above (V), a rolling bearing shown in FIG. 2 will be explained.

A solid lubricant N7 is formed in the rolling element guide circumferential groove 1a of the outer ring l, a solid lubricant layer 8 is formed in the rolling element guide circumference a2a of the inner ring 2, and a plurality of rolling elements 3 are formed in both stations i1a and 2a.
This is similar to the embodiment shown in FIG. 1 in that it is fitted in a rolling manner. The cage 14 that holds the plurality of rolling elements 3 is
- side open type. This retainer 14 is made of PTFE
, ETFB, and other self-lubricating materials. The annular seals 15 and 16 of the annular openings on both sides are sheet metal seals made of sheet metal (made of ferromagnetic material) with mutually symmetrical shapes, and one end of each is fitted and fixed to the annular stepped portions 1d and ld of the outer ring 1. , the other end is a permanent magnet 15 c , 1 which is fitted and fixed to the annular stepped portion 2 d of the inner ring 2 .
6c with a small annular gap therebetween, and this gap is filled with magnetic fluids 15d and 16d.

Incidentally, the above-mentioned (1) to (iv) can be considered as embodiments in which changes are made to the embodiment shown in FIG.

Furthermore, as a modification of the present invention, although it is not an embodiment of the present invention, in the embodiment of FIG. I can think of something that has already been created. The present invention also includes rolling bearings that use rollers instead of balls as the rolling elements 3, rolling bearings in which the rolling elements 3 are made of a self-lubricating material such as carbon, and rolling bearings that do not have a cage. This can be considered as an embodiment or a modification (without a solid lubricant layer).

<Effect of the invention> According to the present invention, the following effects are achieved.

That is, since the solid lubricant layer is formed on the friction surface of any one of the bearing components that undergoes friction, the lubricity can be improved.

Further, even if wear powder is generated and mixed into the magnetic fluid, the concentration of the magnetic fluid does not decrease, and the pressure resistance of the annular seal can be maintained as expected for a long period of time. That is,
Since the annular opening between the outer ring and the inner ring is reliably closed by the annular seal using magnetic fluid, it is possible to reliably prevent wear powder from leaking to the outside.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a rolling bearing according to an embodiment of the present invention. FIG. 2 is a sectional view of main parts according to another embodiment. 1... Outer ring 2... Inner ring 3... Rolling elements 4.14... Cage 4a... Inner surface of cage 5, 15.16... Annular seal using magnetic fluid 5 c
, 15c, 16cm...Permanent magnet 5d, 15d,
16d...Magnetic fluid 7.8...Solid lubricant layer

Claims (8)

[Claims] (1) In a rolling bearing in which rolling elements are rollably interposed between an outer ring and an inner ring, at least one of the annular openings on both sides between the outer ring and the inner ring is an annular opening using a magnetic fluid. Solid lubrication is applied to the friction surface of at least one of the bearing components that is closed by a seal and receives friction as the rolling elements roll among a plurality of bearing components including the outer ring, inner ring, and rolling elements. A rolling bearing characterized by having an agent layer formed thereon. (2) The rolling bearing according to claim 1, wherein the bearing components that undergo friction as the rolling elements roll are the outer ring, the inner ring, and the rolling elements. (3) The rolling bearing according to claim (1), wherein the bearing components that receive friction as the rolling elements roll are the outer ring, the inner ring, the rolling elements, and a cage that holds the rolling elements. . (4) Claims (1), (2), and (3) in which the solid lubricant layer is formed on the raceway surface of the outer ring.
) The rolling bearing described in any one of the above items. (5) Claims (1), (2), and (3) in which the solid lubricant layer is formed on the raceway surface of the inner ring.
) The rolling bearing described in any one of the above items. (6) Claims (1), (2), and (3), wherein the solid lubricant layer is formed on the surface of the rolling element.
) The rolling bearing described in any one of the above items. (7) The rolling bearing according to claim (3), wherein the solid lubricant layer is formed on the inner surface of the retainer. (8) Claims (3), (4), and (5), wherein the retainer is made of a self-lubricating material;
The rolling bearing according to any one of item (6).