JP3782878B2 - Slide bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plain bearing device in which a sleeve and a shaft are fitted with a minute gap so as to be relatively rotatable.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a hydrodynamic bearing device which is a kind of a sliding bearing device is used as a bearing device that rotatably supports a rotating anode of an X-ray tube, for example.
FIG. 5 is a cross-sectional view of an essential part showing an example of a conventional hydrodynamic bearing device. In this hydrodynamic bearing device, a shaft 92 is rotatably introduced into a cylindrical sleeve 91 whose one end is closed by a lid 93, and between the sleeve 91 and the shaft 92 and between the shaft 92 and the lid 93. Are filled with a liquid metal 94 for lubrication such as liquid gallium.
A small hole 95 for filling the liquid metal 94 is formed in the lid 93, and the small hole 95 is closed by screwing a plug 96 with a bolt after filling the liquid metal 94. .
[0003]
[Problems to be solved by the invention]
However, in the above hydrodynamic bearing device, although the small hole 95 is closed by the plug 96, a minute gap is formed between the two, so that the liquid metal 94 leaks through the gap and the atmosphere around the bearing device is obtained. There was a problem of being contaminated. This contamination of the atmosphere has been a particularly serious problem when the hydrodynamic bearing device such as the X-ray tube is used in a vacuum.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a plain bearing device capable of preventing liquid metal from leaking through a small hole.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, a sliding bearing device according to the present invention introduces a shaft into a cylindrical sleeve whose one end is closed with a lid so as to be relatively rotatable, and a gap between the shaft and the sleeve and the lid. Further, in the sliding bearing device which is filled with the liquid metal for lubrication and has a small hole for filling the liquid metal in the lid, and the small hole is closed by the plug, the plug and the small hole Alternatively, the gap between the lid and the lid is sealed with a reaction film formed by reacting with the liquid metal (claim 1).
According to the slide bearing device having the above configuration, the gap between the stopper and the small hole is sealed by the reaction film generated by reacting with the liquid metal, so that the liquid metal leaks through the gap. Can be prevented.
[0005]
The reaction membrane may be produced by reacting a plug material with a liquid metal (Claim 2), and in this case, the reaction membrane is formed without applying any special treatment to the plug. Can do.
In the slide bearing device, the stopper may be a bolt and a washer, and the reaction film may be generated on at least one of the bolt and the washer. In this case, the reaction film can prevent the liquid metal from leaking through the gap between the bolt and the small hole or the gap between the washer and the lid.
[0006]
In the slide bearing device, the stopper is made of a bolt and a washer, at least one of the bolt and the washer is made of stainless steel, the lid is made of a molybdenum alloy, and the liquid metal is made of gallium or a gallium alloy. (Claim 4). In this case, the reaction film can be generated only by heating the apparatus to a predetermined temperature.
The reaction film may be formed by reacting a coating agent applied to at least one of the stopper and the small hole with a liquid metal (Claim 5). In this case, the stopper is excessive with the liquid metal. It is possible to prevent the reaction film from reacting and to produce the reaction film regardless of the material of the stopper.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 2 is a cross-sectional view of an essential part showing a hydrodynamic bearing device according to one embodiment of the plain bearing device of the present invention. In the figure, the hydrodynamic bearing device has one end of a cylindrical sleeve 1 closed with a lid 2 and a shaft 3 is introduced with a minute gap inside the sleeve 1. Between the shaft 3, the sleeve 1 and the lid 2, a liquid metal 4 for lubrication made of gallium or a gallium alloy is filled.
[0009]
The lid body 2 is a disc-shaped body made of a molybdenum alloy, and is screwed to the end surface of the sleeve 1. A small hole 6 for filling the liquid metal 4 is formed in a portion of the lid body 2 facing the end surface 3 b of the shaft 3, and the small hole 6 is closed by a plug 7.
Referring also to FIG. 1, the plug 7 includes a bolt 7 a screwed into the small hole 6, and a washer 7 b interposed between the head of the bolt 7 a and the lid body 2. The bolt 7 a is entirely made of stainless steel, and the surface of the screw portion is covered with a reaction film 8. As the stainless steel forming the stopper 7, iron-based, nickel-based, or chromium-based ones are used.
[0010]
The reaction film 8 is obtained by heating the hydrodynamic bearing device to, for example, 200 ° C., and liquid metal 4 in which stainless steel as a material of the bolt 7 a is permeated into a minute gap between the bolt 7 a and the small hole 6. The reaction film 8 is generated by reacting and corroding, and the minute gap between the bolt 7 a and the small hole 6 is sealed by the reaction film 8. For this reason, it is possible to prevent the liquid metal 4 filled between the shaft 3 and the sleeve 1 and the lid body 2 from leaking through the minute gap between the bolt 7a and the small hole 6, and thus the atmosphere is reduced. It can be prevented from being contaminated. Specifically, the reaction film 8 is made of FeGa ₃ , Fe ₈ Ga ₁₁ , iron (Fe), chromium (Cr), nickel (Ni) in stainless steel produced by reaction with gallium (Ga), It consists of reactants such as Cr ₃ Ga and NiGa ₄ .
In particular, in this embodiment, since the reaction film 8 is generated by reacting the material of the bolt 7a with the liquid metal 4, the bolt 7a is subjected to a special treatment for oxidation, such as application of a coating agent. The reaction film 8 can be produced without any problems. Accordingly, the reaction film 8 can be easily generated.
[0011]
A groove 3a for generating radial dynamic pressure is formed on the outer peripheral surface of the shaft 3, and the shaft 3 is supported in the radial direction by the pumping action of the groove 3a due to relative rotation between the sleeve 1 and the shaft 3. Can do. Further, the shaft 3 can be supported in the thrust direction by the fluid pressure of the liquid metal 4 interposed between the end surface 3 b of the shaft 3 and the lid 2.
[0012]
In the above embodiment, the reaction film 8 is generated on the bolt 7a, but it may be generated on the washer 7b (see FIG. 3). In this case, the bolt 7a is formed of, for example, a molybdenum alloy that does not react with the liquid metal 4, the washer 7b is formed of stainless steel, and the gap between the washer 7b and the lid 2 and the head of the washer 7b and the bolt 7a. By corroding the washer 7b with the liquid metal 4 that has penetrated into the gap between the portions 7c, the gap is sealed by the generated reaction film 8. Note that both the bolt 7a and the washer 7b may be formed of stainless steel, and the reaction film 8 may be formed on both the bolt 7a and the washer 7b. Moreover, you may make it ensure the sealing performance between the head 7c of the volt | bolt 7a, and the washer 7b, for example by finishing both contact surfaces accurately.
[0013]
The reaction film 8 may be formed by applying a coating agent to at least one of the stopper 7 and the small hole 6 and reacting the coating agent with the liquid metal 4. It is possible to prevent the reaction film 8 from being excessively generated by reacting with the liquid metal 4 excessively, and an arbitrary material can be selected as the material of the stopper 7. As the coating agent, when the stopper 7 and the lid 2 are made of, for example, a molybdenum alloy, an iron-based one is used. When the stopper 7 is made of stainless steel, molybdenum is used.
In addition, the materials of the bolt, washer and coating agent to be reacted with the liquid metal react with the liquid metal at a temperature lower than the material used for the bearing body in addition to those mentioned in the above embodiment, and As long as it does not react with the liquid metal at the service temperature of the bearing, various materials can be used as long as the strength and other conditions are satisfied.
[0014]
FIG. 4 is a cross-sectional view of a main part showing another embodiment. In this embodiment, the bolt 7a is formed of a softer metal than the lid body 2, and the bolt 7a is screwed into the small hole 6 to deform the screw thread. Thus, the liquid metal 4 is prevented from leaking through the small hole 6.
When the lid 2 is formed of a molybdenum alloy, the material of the bolt 7a is selected from molybdenum, niobium, and tungsten. Thereby, it can prevent that the volt | bolt 7a reacts with a liquid metal, and can ensure the durability.
[0015]
In the embodiment shown in FIG. 4, the lid 2 and the bolt 7a may be formed of a molybdenum alloy, and the washer 7b may be selected from molybdenum, niobium, and tungsten, which are softer than the lid 2 and the bolt 7a. In this case, by screwing the bolt 7 a into the small hole 6, the washer 7 b can be deformed and brought into close contact with the lid body 2 and the head portion 7 c of the bolt 7 a, whereby the liquid metal 4 leaks through the small hole 6. Can be prevented. Alternatively, the lid 2 may be formed of a molybdenum alloy, and both the bolt 7a and the washer 7b may be selected from molybdenum, niobium, and tungsten that are soft in the lid 2. In this case, the bolt 7a may be a small hole 6 In addition, the washers 7 b can be brought into close contact with the lid body 2 to prevent the liquid metal 4 from leaking through the small holes 6.
[0016]
【The invention's effect】
As described above, according to the slide bearing device of the present invention, the gap between the stopper and the small hole is sealed with the reaction film generated by reacting with the liquid metal, and the liquid metal leaks through the gap. Therefore, it is possible to prevent the atmosphere around the slide bearing device from being contaminated.
[0017]
According to the slide bearing device of the second aspect, since the reaction film is formed by reacting the plug material with a liquid metal, it is not necessary to perform special treatment on the plug, and the reaction film can be easily formed. Can be formed.
According to the slide bearing device according to claim 3, the liquid film can be prevented from leaking from the small hole portion by the reaction film formed on at least one of the bolt and the washer constituting the stopper. It is possible to prevent the ambient atmosphere of the air from being contaminated.
According to the sliding bearing device of claim 4, at least one of the bolt and the washer constituting the stopper is made of stainless steel, the lid is made of molybdenum alloy, and the liquid metal is made of gallium or gallium alloy. The reaction film can be produced simply by heating to a temperature.
[0018]
According to the slide bearing device of claim 5, since the reaction film is formed by reacting the coating agent applied to at least one of the stopper and the small hole with the liquid metal, the stopper is excessive with the liquid metal. it is possible to prevent the reaction, it is possible to ensure the durability, regardless the plug material, Ru can generate the reaction layer.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part showing a fluid dynamic bearing device according to one embodiment of the present invention.
2 is the same KuKaname sectional view.
FIG. 3 is an enlarged cross-sectional view of a main part showing another embodiment.
FIG. 4 is an enlarged cross-sectional view of a main part showing still another embodiment.
FIG. 5 is a cross-sectional view of a main part showing a conventional example.
[Explanation of symbols]
1 Sleeve 2 Lid 3 Shaft 4 Liquid Metal 6 Small Hole 7 Plug 7a Bolt 7b Washer 8 Reaction Membrane

Claims (5)

  A shaft is introduced into a cylindrical sleeve whose one end is closed with a lid so as to be relatively rotatable, and a gap between the shaft and the sleeve and the lid is filled with a liquid metal for lubrication, and In a slide bearing device in which a small hole for filling a liquid metal is formed in a lid, and the small hole is closed with a stopper, the gap between the stopper and the small hole or the lid reacts with the liquid metal. A sliding bearing device characterized in that it is sealed by a reaction film produced by the process.   The plain bearing device according to claim 1, wherein the reaction film is formed by reacting a plug material with a liquid metal.   The plain bearing device according to claim 1, wherein the stopper includes a bolt and a washer, and the reaction film is generated on at least one of the bolt and the washer.   2. The plain bearing device according to claim 1, wherein the stopper is made of a bolt and a washer, at least one of the bolt and the washer is made of stainless steel, the lid is made of a molybdenum alloy, and the liquid metal is made of gallium or a gallium alloy.   2. The plain bearing device according to claim 1, wherein the reaction film is formed by reacting a coating agent applied to at least one of the stopper and the small hole with a liquid metal.

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