JPH1193946A - Sliding bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and quickly perform the fitting of a shaft to a sleeve by forming an oxidized layer for preventing the adhesion of a liquid metal on the inside surface of the opening part of the sleeve and the circumferential surface of the shaft opposed to the inner surface. SOLUTION: A liquid metal 4 is filled in the range excluding the parts of oxidized layers S1, S2 of the clearance between a sleeve 1 and a shaft 3, and the liquid metal 4 is prevented from being leaked from the opening part 11 side of the sleeve 1 according to the relative rotations of the sleeve 1 and the shaft 3. Even if the liquid metal 4 applied to the shaft 3 and the sleeve 1 is transferred to the opening part 11 side of the sleeve 1 when the shaft 3 is inserted to the sleeve 1 in the assembling process of a dynamic pressure bearing device, the liquid metal 4 is repelled by the oxidized layers S1, S2, and the transfer is arrested. Accordingly, the liquid metal 4 can be prevented from being adhered to the part of the oxidized layers S1, S2, and the lid body 2 can be easily and quickly fitted to the sleeve 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing device in which a sleeve and a shaft are fitted with a small clearance so as to be relatively rotatable.

[0002]

2. Description of the Related Art Conventionally, a hydrodynamic bearing device, which is a kind of a sliding bearing device, is used as a vacuum bearing device for rotatably supporting a rotating anode of an X-ray tube, for example. FIG. 4 is a sectional view of an essential part showing an example of a conventional hydrodynamic bearing device. In this dynamic pressure bearing device, a shaft 92 is rotatably introduced into a cylindrical sleeve 91 one end of which is closed by a lid 93, and the shaft 92 is interposed between the sleeve 91 and the shaft 92 and between the shaft 92 and the lid 93. Liquid metal 94 such as liquid gallium for lubrication.
Is filled. The liquid metal 94 is filled except for a predetermined range A of the opening 91a of the sleeve 91, thereby preventing the liquid metal 94 from leaking from the opening 91a.

[0003]

At the time of assembling the above-mentioned hydrodynamic bearing device, the shaft 92 is inserted into the sleeve 91 with the liquid metal 94 applied to the sleeve 91 and the shaft 92 in advance. However, when the shaft 92 is inserted, the applied liquid metal 94 may be pushed to the opening 91 a of the sleeve 91. The liquid metal 94 pushed to the opening 91a leaks when the shaft 92 rotates, and contaminates the atmosphere around the bearing device. The contamination of this atmosphere is based on the above X
Particularly serious problems occur when a dynamic pressure bearing device such as a wire tube is used in a vacuum. Therefore, it is necessary to insert the shaft 92 into the sleeve 91 with great care so that the liquid metal 94 does not move to the opening 91a side of the sleeve 91, and there is a problem that the assembly is difficult. If the liquid metal 94 moves to the opening 91a of the sleeve 91, the shaft 92 is pulled out of the sleeve 91, the liquid metal 94 transferred to the opening 91a is wiped off, and then the shaft 92 is inserted again. Work is required, and in some cases, a large number of man-hours are required for assembly. The present invention has been made in view of the above problems, and has as its object to provide a slide bearing device that can easily and quickly incorporate a shaft into a sleeve.

[0004]

According to a first aspect of the present invention, there is provided a plain bearing device in which a shaft is rotatably introduced into a cylindrical sleeve, and a gap between the sleeve and the shaft is provided. In the sliding bearing device filled with the liquid metal for lubrication, the liquid metal is prevented from adhering to the inner peripheral surface of the opening of the sleeve and the outer peripheral surface of the shaft facing the inner peripheral surface. An oxide layer is formed (claim 1).

According to the above-described plain bearing device, even if the liquid metal tries to move toward the opening of the sleeve when the shaft is inserted into the sleeve, the liquid metal is repelled by the oxide layer to form the liquid metal. It is possible to prevent metal from adhering to the inner peripheral surface of the opening of the sleeve and the outer peripheral surface of the shaft facing the inner peripheral surface.

It is preferable that the oxidized layer is formed by oxidizing the surface of the material of the sleeve and the shaft (claim 2). Mixing can be prevented. In the above-mentioned plain bearing device, a stepped portion protruding in the radial direction may be formed on the outer periphery of the shaft, and the oxide layer may be formed on the stepped portion. In this case, the step can prevent the liquid metal from moving toward the opening edge of the sleeve. Therefore, even when a large amount of liquid metal is applied to the sleeve or the shaft, the liquid metal is prevented from adhering to the inner peripheral surface of the opening of the sleeve and the outer peripheral surface of the shaft facing the inner peripheral surface. can do.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of an essential part showing a hydrodynamic bearing device according to an embodiment of the sliding bearing device of the present invention. In the figure, in the above-mentioned hydrodynamic bearing device, a shaft 3 is introduced with a small gap into a cylindrical sleeve 1 one end of which is closed by a lid 2. In the gap between 2,
Liquid metal 4 for lubrication is filled.

The sleeve 1 is made of a molybdenum alloy, and has an enlarged diameter portion 12 formed on an inner periphery of an opening portion 11 thereof.
An oxide layer S1 for preventing the liquid metal 4 from adhering is formed on the entire circumference from the side wall to the side wall 12b (see FIG. 2). The oxide layer S1 is formed by exposing a surface layer portion of the molybdenum alloy as a material of the sleeve 1 corresponding to the oxide layer S1 to a high temperature in the atmosphere.

A stepped portion 31 is formed on a portion of the outer periphery of the shaft 3 facing the enlarged diameter portion 12 so as to protrude radially outward. The stepped portion 31 is provided with the enlarged diameter portion 1 of the sleeve 1.
2 and the outer periphery and the enlarged diameter portion 1 of the sleeve 1
2 is set to about 0.1 mm. An oxide layer S2 for preventing the liquid metal 4 from adhering is formed on a portion of the outer periphery of the shaft 3 facing the oxide layer S1 of the sleeve 1. The oxide layer S2 is formed by exposing a surface layer portion of the molybdenum alloy as the material of the shaft 3 corresponding to the oxide layer S2 to a high temperature in the air. A groove 32 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 a pumping action of the groove 32 due to relative rotation between the sleeve 1 and the shaft 3. Can be.
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 33 of the shaft 3 and the lid 2.

The liquid metal 4 is filled in the gap between the sleeve 1 and the shaft 3 excluding the oxide layers S1 and S2, so that the relative rotation between the sleeve 1 and the shaft 3 is reduced. Accordingly, leakage of the liquid metal 4 from the opening 11 side of the sleeve 1 is prevented. The liquid metal 4 is a cover 2
After the shaft 3 is inserted into the sleeve 1 with the
The gap between the sleeve 1 and the shaft 3 is filled through the opening on the side, and a part of the gap is previously applied to both before the shaft 3 is inserted into the sleeve 1. As the liquid metal 4, gallium, a gallium alloy, mercury, sodium, or the like is used. The gap between the sleeve 1 and the shaft 3 is set to about 10 μm. The lid 2 is
It has a disk shape and is screwed to the end surface of the sleeve 1.

With the above configuration, when the shaft 3 is inserted into the sleeve 1 in the assembly process of the dynamic pressure bearing device,
Even if the liquid metal 4 applied to the shaft 3 and the sleeve 1 tries to move toward the opening 11 of the sleeve 1, the liquid metal 4 is repelled by the oxide layers S1 and S2, and the transfer is prevented. Therefore, the liquid metal 4 can be prevented from adhering to the portions of the oxide layers S1 and S2, and the cover 2 can be easily and quickly incorporated into the sleeve 1.

Particularly, in the above-described embodiment, since the step 31 projecting in the radial direction is formed in the portion of the oxide layer S2 on the shaft 3 side, the liquid metal 4 is opened by the step 31 Transition to the rim can be restricted. Therefore, a large amount of liquid metal 4 is placed on the sleeve 1 or the shaft 3.
Is applied to the inner peripheral surface of the enlarged diameter portion 12 of the sleeve 1 and the outer peripheral surface of the step portion 31 of the shaft 3.
Can be prevented from adhering.

In addition, since the oxide layers S1 and S2 are obtained by oxidizing the material of the sleeve 1 and the shaft 3, the oxide layers S1 and S2 are hardly peeled off. In addition, the occurrence of poor lubrication can be prevented for a long period of time.

The above-mentioned hydrodynamic bearing may be one in which the lid 2 is eliminated and both ends of the sleeve 1 are formed as openings 11 and the shaft 3 is inserted through the sleeve 1. According to each of the openings 11 and 13 on both sides,
The oxide layers S1 and S2 may be formed (see FIG. 3).
The present invention is not limited to the above-described embodiment. For example, the enlarged diameter portion 12 of the sleeve 1 and the step portion 31 of the shaft 3
, And various design changes can be made, such as forming the oxide layers S1 and S2 with an oxide coating. Further, the present invention can be applied to not only the above-described hydrodynamic bearing device but also a sliding bearing in which the shaft 3 does not have the groove 32 for generating a radial dynamic pressure.

[0015]

As described above, according to the sliding bearing device of the present invention, when the shaft is inserted into the sleeve, the inner peripheral surface of the opening of the sleeve and the outer peripheral surface of the shaft facing the inner peripheral surface are formed. Since the adhesion of the liquid metal can be prevented by the oxide layer, the shaft can be easily and quickly inserted, and the number of assembling steps of the slide bearing device can be reduced.

According to the sliding bearing device of the present invention, since the oxidized layer is formed by oxidizing the material surfaces of the sleeve and the shaft, the oxidized layer is hardly peeled off, and the particles are mixed with the liquid metal. Therefore, it is possible to prevent the problem of poor lubrication from occurring over a long period of time.

According to the sliding bearing device of the third aspect,
The stepped portion protruding from the outer periphery of the shaft can prevent the liquid metal from migrating to the opening edge side of the sleeve.
Even when a large amount of liquid metal is applied to the sleeve or the shaft, it is possible to prevent the liquid metal from adhering to the inner peripheral surface of the opening of the sleeve and the outer peripheral surface of the shaft facing the inner peripheral surface. it can. For this reason, the shaft can be more easily and quickly inserted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a dynamic bearing device according to one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the same.

FIG. 3 is a cross-sectional view of a main part showing another embodiment.

FIG. 4 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sleeve 11 Opening 2 Lid 3 Shaft 31 Stepped part 4 Liquid metal S1 Oxide layer S2 Oxide layer

Claims (3)

[Claims] 1. A sliding bearing device wherein a shaft is rotatably introduced into a cylindrical sleeve, and a gap between the sleeve and the shaft is filled with a lubricating liquid metal. A sliding bearing device, wherein an oxide layer for preventing the liquid metal from adhering is formed on an inner peripheral surface of the opening and an outer peripheral surface of a shaft opposed to the inner peripheral surface. 2. The sliding bearing device according to claim 1, wherein said oxide layer is obtained by oxidizing the surface of a material of a sleeve and a shaft. 3. The sliding bearing device according to claim 1, wherein a stepped portion is formed on an outer periphery of said shaft so as to project in a radial direction, and said oxide layer is formed on said stepped portion.