JP2001099171A - Rolling bearing and bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve seal performance under a particular environment, in a rolling bearing. SOLUTION: This rolling bearing 5, sealing inner/out rings 9, 10 with a lubricant to be set up in a form of one shaft end side facing a vacuum space A, is used with a pressure resistance seal 6 maintaining a degree of vacuum of the vacuum space in a shaft end in a vacuum space side, so as to improve seal performance under a particular environment by this pressure resistance seal. Here, the inner/outer rings are formed of anticorrosion material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rolling bearing in which a lubricant is sealed between an inner ring and an outer ring and one shaft end of which faces a vacuum space, and a seal and the rolling bearing. The present invention relates to a bearing unit provided.

[0002]

2. Description of the Related Art In a conventional rolling bearing, an oil seal is used as a seal for sealing a lubricant between an inner ring and an outer ring.

[0003] The oil seal is formed by attaching an elastic body to an annular cored bar and forming an inner peripheral portion of the elastic body as a lip that slides on a rotating member. The oil seal is provided at each of both shaft ends between the inner and outer rings. The main purpose is to use a gap between the lip and the rotating member as a sealed portion and prevent oil from leaking therefrom.

[0004]

When such a rolling bearing rotatably supports a rotating shaft in a housing,
In some cases, the annular space between the housing and the rotary shaft is partitioned into two spaces, a space to be sealed by vacuum, and an atmospheric pressure space by an oil seal.

[0005] However, in such a special environment,
Since the pressure difference between the two surfaces of the oil seal is excessive, gas or the like on the atmospheric pressure space side leaks into the space to be sealed through the above-mentioned sealed portion, and the degree of vacuum of the space to be sealed is reduced, for example. Is low.

[0006] When a bearing ring of a rolling bearing is made of bearing steel, an antioxidant is usually applied to the bearing ring to protect the bearing ring. However, such a rolling bearing is arranged in a vacuum space. Under such circumstances, the atmosphere of the vacuum space is contaminated by the antioxidant. On the other hand, if an antioxidant is not applied to the bearing ring, the bearing ring is oxidized before the rolling bearing is incorporated into a use site, and the oxidized component contaminates the vacuum space side.

[0007] Accordingly, the present invention has a common solution to improve the sealing performance under the above-mentioned special environment by using a pressure-resistant seal in a rolling bearing.

Another object of the present invention is to prevent the contamination of the vacuum space side by the oxidizing component of the race when the rolling bearing is disposed in the vacuum space.

Further, the present invention provides a bearing unit in which a rolling bearing and a seal are combined, by using a pressure-resistant seal to improve the sealing performance under the above-mentioned special environment, and to provide a raceway when disposed in a vacuum space. Another problem is to prevent contamination of the vacuum space side by an antioxidant component of the wheel.

[0010]

Means for Solving the Problems (1) In the rolling bearing of the present invention, a lubricant is sealed between the inner and outer rings, and
On the other hand, a rolling bearing is installed in a form in which the shaft end side faces a vacuum space of 10 ⁻⁴ Pa or less, and the one shaft end side includes:
It is characterized in that a pressure-resistant seal for maintaining the degree of vacuum in the vacuum space is mounted.

In the rolling bearing according to the present invention, preferably, the inner and outer rings are formed of a corrosion-resistant material.

In the rolling bearing of the present invention, preferably, a pressure-resistant seal for maintaining the degree of vacuum in the vacuum space is also mounted on the other end of the shaft facing the atmospheric pressure space.

(2) In the bearing unit of the present invention,
The rotating member is supported on the inner circumference of the case via a rolling bearing,
And a bearing unit installed in a form in which one side of the annular space between the housing and the rotating member, which sandwiches the rolling bearing, communicates with the vacuum space, and the other side communicates with the atmospheric pressure space. A pressure-resistant seal is provided in the space on the vacuum space side of the rolling bearing.

[0014] In the bearing unit of the present invention, preferably, a pressure-resistant seal is provided also on the atmospheric pressure space side of the rolling bearing.

In the bearing unit of the present invention, preferably, a plurality of the pressure-resistant seals are juxtaposed adjacently in the axial direction at least on the vacuum space side.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view schematically showing a vacuum chamber equipped with a rotation introducing machine, and FIG. 2 is an enlarged sectional view of a bearing unit in the rotation introducing machine of FIG.

Referring to FIG. 1, a vacuum chamber 1 performs a required operation, for example, transfer of a work, while maintaining the inside of the vacuum chamber in a vacuum state.

In the vacuum chamber 1, a rotation introducing machine 2 is mounted in a rotation introducing machine mounting hole in the chamber wall in order to introduce rotation required for the transfer operation.

The rotation introducing machine 2 is disposed, for example, over the inside and outside of the chamber wall of the vacuum chamber 1 and introduces rotation power for carrying a work in the chamber.

The rotation introducing machine 2 includes a housing 3, a rotating shaft 4, a rolling bearing 5, and a pressure-resistant seal 6.

The housing 3 has its mounting flange 7 fixed to the chamber wall by screws 8 and mounted in a mounting hole in the chamber wall.

The rotating shaft 4 is inserted through the inside and outside of the housing 3 and is rotatably supported in the housing 3 by a rolling bearing 5.

Referring to FIG. 2, a rolling bearing 5 includes an inner ring 9 and an outer ring 10 as track rings, and inner and outer rings 9 and 1.
It has a plurality of rolling elements 11 that roll between 0 and a plurality of retainers 12 that hold each rolling element 11.

Between the inner and outer rings 9, 10 of the rolling bearing 5,
A lubricant (not shown) is enclosed.

The rolling bearing 5 has one shaft end serving as a vacuum space, that is, a shaft end on the space A to be sealed, the other shaft end serving as a shaft end on the atmospheric pressure space B, and a shaft end on the side of the space A to be sealed. The housing 3 is configured to face the space A to be sealed of 10 ⁻⁴ Pa or less, that is, the vacuum chamber 1 via the pressure-resistant seal 6.
It is installed in.

The pressure-resistant seal 6 includes the housing 1 and the rotating shaft 4.
Are separated into two spaces, a vacuum space, ie, a space A to be sealed, which communicates the annular space facing the inside of the vacuum chamber 1 with the inside of the vacuum chamber 1, and an atmospheric pressure space B which communicates outside the vacuum chamber 1 and in which the rolling bearing 5 is located. The inside and outside of 1 are shut off.

The pressure-resistant seal 6 and the rolling bearing 5 constitute a bearing unit 13 of the embodiment.

Next, the structure of the pressure-resistant seal 6 will be described in detail.

The pressure-resistant seal 6 is constituted by attaching a second seal portion 6b (adhered seal portion) to a first seal portion 6a (main body seal portion).

The first seal portion 6a is formed by annularly attaching an elastic body 15 to an annular core 14 whose upper half has a substantially L-shaped cross section in the radial direction.

The second seal portion 6b has an upper half radial cross section substantially in the shape of a recess, and the lip described later is formed in the space A to be sealed.
An elastic body 17 is annularly attached to a metal ring body 16 for preventing the metal ring body 16 from rolling up in the space A to be sealed due to the negative pressure.

The elastic member 15 in the first seal portion 6a
The main lip 18 extends toward the atmospheric pressure space B, has an upper half cross-sectional shape that is substantially inverted triangle, and has a rounded edge 18a corresponding to its vertex. You. As will be described in detail later, the main lip 18
Since the edge 18a is rounded, the edge 18a slides with a predetermined axial contact width with respect to the rotating shaft 4.

The elastic member 17 in the second seal portion 6b
The end of the rotating shaft 4 side, that is, the inner peripheral portion, is an auxiliary lip 19 having a tapered shape which is separated from the main lip 18 and whose upper half cross-sectional shape gradually decreases toward the space A to be sealed. You.

On the outer periphery of the main lip 18, the rotation
A garter spring 20 that is pressed against the outer peripheral surface of the rim is mounted.

Main lip 18, auxiliary lip 19 and rotary shaft 4
And lubricant 4 such as oil or grease in the space surrounded by
0 is filled.

Here, the elastic members 15, 1 of the pressure-resistant seal 6 are used.
7, particularly the material of the lips 18, 19 will be described in detail. Under the special environment described above, an excessive pressure difference is applied to the lip, and the gas in the atmospheric pressure space side is transmitted through the lip itself toward the sealed space side,
Therefore, as a result of conducting experiments by selecting various materials for the lip with respect to the degree of vacuum of the space to be sealed, under the conditions of use (A) below, gas transmission to the lip is effectively prevented by selecting the material (B) below. It was confirmed that the sealing property was improved.

(A), operating conditions a, pressure in the space to be sealed: 10 ^-4 Pa or less b, leak rate of the sealed fluid from the sealed portion: 10 ^-9 Pam
³ / sec or less c, operating temperature: 25 ° C. The numerical value of the degree of vacuum is one of the operating conditions, and is not necessarily a fixed numerical value, but corresponds to, for example, the degree of internal vacuum required for a vacuum chamber. It is a numerical value. Therefore, in the present invention, the numerical value of the degree of vacuum is not essential in use conditions. Further, the pressure of the atmospheric pressure space with respect to the sealed space having the degree of vacuum is a standard atmospheric pressure.

(B) Material of the lip Of the two spaces sandwiching the lip as in the above-mentioned use condition (A), assuming the degree of vacuum in the space to be sealed, as a material of the lip of the present invention, Nitrogen gas permeability, one of the properties, is 3.225 (cm
^{3 / m 2 / 25μm / 24h} / 25 ℃ pressure) was selected following materials, there is no transmission of the nitrogen gas with respect to the lip and improved sealing performance of the seal.

From the viewpoint of improving the sealing performance under a special environment, which is the object of the present invention, any material having the above gas permeability can be used as the material of the lip. Particularly, when a material mainly composed of a resin or rubber of a fluorine-based material was selected, favorable results were obtained. In addition, the unit of nitrogen gas permeability is omitted.

Fluorine resin , PTFE (ethylene tetrafluoride resin), PFA (ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer resin), FEP (ethylene tetrafluoride-propylene hexafluoropropylene copolymer resin), ETFE ( Ethylene tetrafluoride-ethylene copolymer resin ・ CTFE (ethylene chloride trifluoride resin) ・ PVDF (vinylidene fluoride resin) fluorinated rubber・ vinylidene fluoride rubber ・ ethylene tetrafluoride-propylene rubber ・ ethylene tetrafluoride - with perfluoromethyl vinyl ether rubber, phosphazene-based fluororubber withstand seal 6, as the material of the elastic body 15 and 17, the permeability of nitrogen gas is ^{3.225 (cm 3 / m 2 /} 25μm /
(24 h / 25 ° C. atmospheric pressure) For example, any of the above-mentioned materials is used.

The pressure-resistant seal 6 using such a material is
When the shaft end of the rolling bearing 5 on the side of the space A to be sealed faces the space A to be sealed having a pressure of 10 ^-4 Pa or less, the gas in the atmospheric pressure space B side passes through the lips 18 and 19 itself. A favorable result was obtained in that it hardly permeated to the space A to be sealed, the degree of vacuum in the space A to be sealed was maintained in a predetermined state, and the sealing property was enhanced.

Note that the present invention is not limited to the above-described embodiment, and various modifications are possible.

(1) In the above embodiment, the number of pressure-resistant seals 6 provided at the shaft end of the rolling bearing 5 on the side of the space A to be sealed is one, but the number of installations is one. However, the present invention is not limited to this, and a plurality of installation numbers may be juxtaposed in the axial direction as shown in FIG. Pressure Seal 6
It is preferable that a plurality of (6, 6A, 6B in the axial direction) be provided in the axial direction, as a result, the pressure resistance can be increased and the sealing performance can be further improved.

In the case of FIG. 5 to be described later, the number of pressure-resistant seals 6 provided on the atmospheric pressure space side B may be plural.

(2) In the above embodiment, the rolling bearing 5 has a structure in which the pressure-resistant seal 6 is not provided. In such a structure, a vacuum pressure is applied to one sealing surface of the pressure-resistant seal 6 and an atmospheric pressure is applied to the other sealing surface. As a result, an excessive pressure difference is applied to the pressure-resistant seal 6 itself, resulting in a large structural burden, and Is disadvantageous in terms of

Therefore, as shown in FIG.
For example, an oil seal 21 is provided on the side of the space A to be sealed between the inner and outer rings 9 and 10, and the oil seal 21 is used as a pressure buffer to reduce the pressure difference between both surfaces of the pressure-resistant seal 6. May be extended.

The oil seal 21 is provided not only in the space A to be sealed but also in the atmospheric pressure space B so that the rolling bearing 5 can be sealed in both the space A to be sealed and the atmospheric space B. I do not care.

It should be noted that the oil seal 21 is
a elastic body 21b is attached to the elastic body 21b.
A main lip 21c and an auxiliary lip 21d are formed at an inner peripheral end of the main lip 21c.

Further, since the pressure-resistant seal 6 is provided outside the rolling bearing 5 on the side of the space A to be sealed, there is a possibility that the lubricant leaks out of the rolling bearing 5 although it has a sealing effect of the lubricant. Therefore, when the oil seal 21 prevents the lubricant (not shown) in the rolling bearing 5 from leaking out of the rolling bearing, and reduces the sealing load of the lubricant on the pressure-resistant seal 6,
The pressure-resistant seal 6 can be used exclusively as a pressure-resistant action, and the pressure-resistant effect can be further improved.

(3) In the above-described embodiment, the pressure-resistant seal 6 is provided only at the shaft end of the rolling bearing 5 on the side of the space A to be sealed, but as shown in FIG.
A pressure-resistant seal 6 in the same direction may be provided also on the shaft end on the side.

When the pressure-resistant seals 6 are provided at both shaft ends of the rolling bearing 5 as described above, the rolling bearing 5 can be used for supporting the rotary shaft 4 in the vacuum chamber 1, which is more preferable. .

Further, it is preferable that the possibility that the lubricant component in the rolling bearing 5 leaks to the atmospheric pressure space B side is reduced.

Further, in the same manner as the oil seal 21 described above, the pressure-resistant seal 6 at only one shaft end of the rolling bearing 5 is excessively large in order to partition the annular space into the sealed space A and the atmospheric pressure space B which are vacuum. Although a pressure difference is applied to increase the structural burden, in the case of FIG. 5, the pressure-resistant seal 6 at the other shaft end serves as a pressure buffering material, and the pressure difference applied to the pressure-resistant seal 6 at the one shaft end can be reduced. Life can be extended.

(4) In the above embodiment, the bearing unit 1 in which the pressure-resistant seal 6 is externally attached to the rolling bearing 5
The rolling bearing 5 is not provided with a pressure-resistant seal 6.

With such a bearing unit 13 configuration, since the size of the pressure-resistant seal 6 can be increased, a pressure-resistant seal structure that can obtain a large pressure-resistant effect can be obtained.

In some cases, however, a very large withstand voltage effect is not required.

In such a case, for example, as shown in FIG. 6, a pressure-resistant seal 6 may be provided in the rolling bearing 5, that is, in the space A to be sealed between the inner and outer rings 9, 10. With this arrangement, one sealing target space A sandwiching the pressure-resistant seal 6 in the rolling bearing 5 is sealed from the other atmospheric pressure space B by the pressure-resistant seal 6. In this case, when the pressure-resistant seal 6 is also provided on the side of the atmospheric pressure space B, the rolling bearing 5 itself is a sealed type, and the inside of the rolling bearing 5 itself is sealed from the space A to be sealed and from the atmospheric pressure space B. Will be. Therefore, the space A to be sealed is sealed from the atmospheric pressure space B via the rolling bearing 5 itself, and the sealing performance is further improved.

In such a case, although the size of the pressure-resistant seal 6 is reduced, the rotation introducing machine 2 is formed by using the rolling bearing 5 alone.
And the rotation introducing machine 2 can have a more compact structure.

When the pressure-resistant seal 6 is provided in the rolling bearing 5 as shown in FIG. 6, the inner and outer rings 9, 10 which are not coated with oil for preventing oxidation, have a space A to be sealed. The end face of the side shaft directly faces the space A to be sealed and is placed in an oxidizing atmosphere.

Therefore, the inner and outer rings 9 and 10 are, for example, SUS
By using a corrosion-resistant material such as 440C, even if the inner and outer rings 9 and 10 to which the antioxidant is not applied, the rolling bearing 5 having the inner and outer rings 9 and 10 is incorporated into the use site of the rotation introducing machine. Oxidation of the inner and outer rings 9 and 10 is prevented during this time.

As a result, even if the rolling bearing 5 having the inner and outer rings 9 and 10 is installed in the space A to be sealed, the inside of the space A to be sealed is preferably prevented from being contaminated.

The pressure-resistant seal 6 shown in FIG.
The elastic member 15 is attached to the elastic member 4, but the main lip 18 and the auxiliary lip 19 at the inner peripheral end of the elastic member 15 may have a conventional shape.

Of course, the auxiliary lip 19 in the pressure-resistant seal 6 in FIG. 6 may have the same shape as the auxiliary lip 19 in FIG.

(5) Surface treatment films 30 and 31 may be formed on the surfaces of both lips 18 and 19 and the surface of rotating shaft 4 as shown in FIG.

The materials of the surface treatment films 30 and 31 are soft metals (gold, silver, copper, etc.), fluororesins (polytetrafluoroethylene, etc.), DLC (Diamond Like).
This is a film formed by selecting any one of surface treatment materials such as carbon-based material having all the characteristics between a carbon fired body containing graphite and a diamond film.

In the pressure-resistant seal 6 in which the surface treatment films 30 and 31 are formed on the lips 18 and 19 and the rotating shaft 4, respectively, the lips 18 and 19 slide with respect to the rotating shaft 4 with time. Even when it operates, the soft metal or fluororesin itself acts as a lubricant, and the DLC is a hard film but has excellent sliding characteristics, so that the lips 18, 19 and the rotating shaft 4 reduce the likelihood that each will scratch their surface against each other, resulting in a lip 1
There is no gap between the rotating shafts 8 and 19 and the rotating shaft 4, so that the sealing performance can be maintained well. In addition, the soft metal and the fluorine-based resin have a high degree of adhesion between the lips 18, 19 and the rotating shaft 4 due to their softness, and therefore have a good sealing degree, and further improve the sealing property. Under the above-mentioned special environment, it is particularly preferable because of its excellent sealing performance.

The present invention is not limited to the above-described embodiment.
Although the surface treatment film 31 is formed on the surface of the rotating shaft 4,
The surface of the rotating shaft 4 may be subjected to a film forming treatment using an aqueous solution of a manganese phosphate compound.

Such a manganese phosphate film is preferable because it has not only lubricity itself but also a function of retaining a lubricant such as oil or grease.

Hereinafter, the formation of the manganese phosphate film on the surface of the rotating shaft 4 will be described.

First, the surface of the rotating shaft 4 is subjected to a pretreatment such as washing, and a coating forming treatment using an aqueous solution of a manganese phosphate compound. By this treatment, on the surface of the rotating shaft 4, corrosion of the surface by the manganese phosphate compound and precipitation of manganese phosphate crystals on the surface occur. As a result, on the surface of the rotating shaft 4, fine and shallow irregularities are formed by the above-mentioned corrosion action, and a lubricating film made of a manganese phosphate salt is formed on the entire surface of the rotating shaft 4.

In this case, on the surface of the rotating shaft 4 before the formation of the lubricating film, there are initial irregularities due to the polishing condition at the time of manufacturing, etc., but the initial irregularities are relatively large and unevenly distributed. In particular, deep streak-like dents are scattered in the initial irregularities.

When a manganese phosphate film is formed on the surface of the rotating shaft 4 having such non-uniform initial irregularities, the non-uniform initial irregularities are smoothed out by the uniform fine irregularities formed by the corrosive action. At the same time, the scattered deep streak-shaped dents are also divided and disappear, and minute irregularities are evenly arranged. Therefore, it is reduced,
In addition, on the surface of the manganese phosphate salt film formed over evenly existing unevenness, fine unevenness having a shallow depth is almost evenly formed similarly to the unevenness.

As described above, a manganese phosphate salt film having fine irregularities is formed on the surface of the rotating shaft 4. As a result, the manganese phosphate film is preferable because it has a function of lubricating and retaining a lubricant, and can suppress abrasion of the rotating shaft 4, thereby securing a sealing property with the pressure-resistant seal 6.

The manganese phosphate coating may be formed on at least the sliding portion of the rotating shaft 4 with the pressure-resistant seal 6.

The present invention is not limited to the above-described embodiment.
Although the surface treatment film 31 is formed on the surface of the rotating shaft 4,
An oil-repellent film (referred to as an oil-repellent film) may be formed on the surface of the rotating shaft 4. The material of this film is a fluorine-based oil repellent, which is coated on the surface of the rotating shaft 4.

This treatment makes it difficult for oil to adhere to the surface of the rotating shaft 4 (decrease in wettability). This oil-repellent film is also preferable because the oil repellency prevents the oil component inside the rolling bearing 5 from leaking into the vacuum chamber 1 and can maintain the internal atmosphere well.

The oil-repellent coating does not necessarily need to be formed on the entire surface of the rotating shaft 4, and at least from the sliding portion of the rotating shaft 4 with the pressure-resistant seal 6 to the end in the direction of the space a to be sealed. It may be just formed.

In this case, a water-repellent coating may be formed on the surface of the rotating shaft 4 in order to prevent water from entering the vacuum chamber 1 instead of the lubricating oil used for the rolling bearing 5.

(6) As described in the above embodiment, the inner peripheral edge 18a of the main lip 18 has a rounded shape. The axial contact width W0 during the movement may be managed in a range represented by the following equation (1).

W1 ≦ W0 ≦ W2 (1) Here, W1 is necessary for ensuring the minimum sealing performance with respect to the gap (sealed portion) between the inner peripheral edge of the main lip 18 and the rotating shaft 4. W2 is the axial contact width of the inner peripheral edge at which the sliding resistance of the inner peripheral edge of the main lip 18 with respect to the rotating shaft 4 is at the limit allowable upper limit. It is.

According to an experiment conducted by the present inventors, the above-mentioned W1
Is 0.2 mm, and when W2 is 2.0 mm, preferable results are obtained.

The tightening force (per unit circumference: g /
mm) to adjust the axial contact width W0,
According to an experiment, the W2 is a tightening force of 70 g / mm and the W2 is
In the case of No. 1, when the tightening force was 25 g / mm, preferable results were obtained. Therefore, the range of the tightening force is 25 g / mm.
It is controlled and adjusted at ~ 70 g / mm.

When the above expression (1) is satisfied, the main lip 18 can ensure a favorable sealing performance while not adversely affecting the rotation characteristics of the rotating shaft 4. In this case, the expression (1) can be managed by the interference of the main lip 18 with respect to the rotating shaft 4 or the tightening force of the garter spring 20 with respect to the main lip 18.

(7) In the second seal portion 6b, the auxiliary lip 19 may have a tapered shape whose upper half cross-section gradually decreases in diameter toward the atmospheric pressure space B as shown in FIG.

With such a shape of the auxiliary lip 19,
Since the auxiliary lip 19 slides on the rotating shaft 4 in a structure having a taper in the direction of the main lip 18, the two lips, the main lip 18 and the auxiliary lip 19, which are brought into contact with the rotating shaft 4, are in the atmospheric pressure space. It has a shape in which the contact pressure is increased by the pressure acting from the B side to the sealed space A side.

As a result, even if the pressure applied from the atmospheric pressure space B to the sealed space A is applied to the auxiliary lip 19, the auxiliary lip 19 does not rise from the rotary shaft 4. For this reason, the auxiliary lip 19 is preferable because it contributes to the sealing action under such a special environment as a result of securing the interference with the rotating shaft 4.

Further, since the auxiliary lip 19 is structured as described above, even if the lubricant 40 is drawn into the space A to be sealed strongly due to the pressure difference between the space A to be sealed and the atmospheric pressure space B, the auxiliary lip 19 can be used. Due to the above-mentioned tapered shape, the lubricant 40 can be held with high holding ability in the space between the main lip 18 and the auxiliary lip 19. As a result, the lubricant 40 can be stably supplied to the sliding surface of the main lip 18 with the rotating shaft 4 for a long period of time, whereby the early prevention of wear of the main lip 18 can be stably prevented, which is preferable. .

In this case, since the auxiliary lip 19 does not rise from the rotary shaft 4, the main lip 18, the auxiliary lip 19, and the rotary shaft 4 are connected to each other even if the lubricant 40 is in a liquid state and has no shape-retaining property. As a result, the enclosed space is better sealed, and the lubricant 40 can be well held in the space.
It is preferable because a commercially available and inexpensive lubricant 40 can be used.

Further, as a result of the above-described structure of the auxiliary lip 19, the lubricant 40 can be favorably held, and as a result, the lubricant 40 leaks to the space A to be sealed, that is, the space A in the vacuum chamber 1, This is a particularly preferable seal when there is no risk of polluting the environment and it is necessary to maintain the inside of the vacuum chamber 1 in a clean atmosphere.

[0091]

(1) In the rolling bearing of the present invention,
At the shaft end on the vacuum space side, a pressure-resistant seal that maintains the degree of vacuum in the vacuum space is used, so that it has a preferable structure for improving the sealing performance under the above-described special environment compared to the oil seal. .

In this case, if the bearing ring is formed of a corrosion-resistant material, the rolling bearing can be rotated by the rotation introducing machine even if the shaft end face on the vacuum space side is directly facing the vacuum space under an oxidizing atmosphere. Oxidation of the bearing ring until it is incorporated into the use site of the vehicle is prevented. As a result, even if the rolling bearing is installed in a vacuum space, it is preferable that the vacuum space is not contaminated.

In this case, if a pressure-resistant seal is also used at the shaft end on the atmospheric pressure space side, the rolling bearing can be used for supporting the rotating shaft in a vacuum environment such as a vacuum chamber. Is more preferable. It is also preferable that the possibility that the lubricant component in the rolling bearing leaks to the atmospheric pressure space side is reduced.

Further, in the pressure-resistant seal of only one shaft end of the rolling bearing, an excessive pressure difference is applied to partition the annular space between the vacuum space and the atmospheric pressure space, and a structural burden is increased. If a pressure-resistant seal is also provided,
On the other hand, it is also preferable that the pressure-resistant seal at the shaft end becomes a pressure buffering material, so that the pressure difference applied to the pressure-resistant seal at the shaft end can be reduced, and the life of the pressure-resistant seal can be extended.

(2) In the bearing unit of the present invention,
Since the pressure-resistant seal is provided between the case and the rotating member on the vacuum space side of the rolling bearing, the sealing performance under the above-described special environment can be improved.

In this case, if a pressure-resistant seal is also provided on the atmospheric pressure space side of the rolling bearing, the pressure-resistant seal on the atmospheric pressure space side becomes a pressure buffer material, and the pressure difference applied to the pressure-resistant seal on the vacuum space side can be reduced. It is also preferable to extend the life of the pressure-resistant seal.

In this case, it is preferable that a plurality of the pressure-resistant seals are provided at least on the vacuum space side of the rolling bearing, because the pressure-resistant effect can be further improved.

Further, since the shaft end of the rolling bearing on the vacuum space side is sealed with a pressure-resistant seal installed therein, even if the anti-oxidant is not applied to the inner and outer rings of the rolling bearing, the inner and outer rings are not sealed. There is no danger of the outer ring being oxidized, and the oxidized component does not contaminate the vacuum space side.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a rotation introducing machine with a built-in bearing unit and a vacuum chamber equipped with the same according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of an upper half of the bearing unit of FIG. 1;

FIG. 3 is an enlarged longitudinal sectional view of an upper half of another modification of the bearing unit of FIG. 1;

FIG. 4 is an enlarged longitudinal sectional view of an upper half of still another modification of the bearing unit of FIG. 1;

FIG. 5 is an enlarged longitudinal sectional view of an upper half of still another modified example of the bearing unit of FIG. 1;

FIG. 6 is an enlarged longitudinal sectional view of an upper half of another modification of the rolling bearing in the bearing unit of FIG. 1;

FIG. 7 is an enlarged longitudinal sectional view of an upper half of still another modified example of the bearing unit of FIG. 1;

FIG. 8 is an enlarged longitudinal sectional view of an upper half of still another modified example of the bearing unit of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 vacuum chamber 2 rotation introducing machine 3 housing 4 rotating shaft 5 rolling bearing 6 pressure-resistant seal 7 mounting flange 9 inner ring 10 outer ring 11 rolling element 13 bearing unit 21 oil seal A space to be sealed B atmospheric pressure space

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazunori Hayashida 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Inside Koyo Seiko Co., Ltd. (72) Inventor Kazutoshi Yamamoto 3-58-8 Minamisenba, Chuo-ku, Osaka-shi Koyo Seiko (72) Inventor Shinichi Obayashi 39 Nishino, Kasagi-shi, Aizumi-cho, Itano-gun, Tokushima Pref. BA54 BA70 BA73 EA33 EA49 EA51 EA78 FA13 GA57

Claims (6)

[Claims] 1. A rolling bearing in which a lubricant is sealed between an inner ring and an outer ring and one shaft end side is installed in a form facing a vacuum space of 10 ^-4 Pa or less, (3) A rolling bearing, wherein a pressure-resistant seal for maintaining a degree of vacuum in a vacuum space is mounted. 2. The rolling bearing according to claim 1, wherein said inner and outer rings are formed of a corrosion-resistant material. 3. The rolling bearing according to claim 1, further comprising a pressure-resistant seal for maintaining the degree of vacuum in the vacuum space also on the other shaft end facing the atmospheric pressure space. Rolling bearings. 4. A rotating member is supported on the inner periphery of the housing via a rolling bearing, and one side of the annular space between the housing and the rotating member, which sandwiches the rolling bearing, is in a vacuum space, and the other side is a vacuum space. A bearing unit installed in such a manner that each of its sides communicates with an atmospheric pressure space, wherein a pressure-resistant seal is installed on the vacuum space side of the rolling bearing in the annular space. 5. The bearing unit according to claim 4, wherein a pressure-resistant seal is provided also on the atmospheric pressure space side of the rolling bearing. 6. The bearing unit according to claim 4, wherein a plurality of the pressure-resistant seals are juxtaposed adjacently in the axial direction at least on the vacuum space side.