JP3788860B2 - 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. 4 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.
The lid 93 has a flat disk shape, and after the shaft 92 is introduced into the sleeve 91 and the gap between them is filled with the liquid metal 94, it is attached to the sleeve 91 using screws or the like.
[0003]
[Problems to be solved by the invention]
In the above hydrodynamic bearing device, when an atmospheric gas such as air remains in the gap between the end surface 92a of the shaft 92 and the lid 93 when the lid 93 is attached to the sleeve 91, the liquid metal 94 is removed in the gap. As a result, it is difficult to form a lubricating film due to oxidization, and the liquid metal 94 is easily oxidized and solidified. As a result, there arises a problem that smooth relative rotation between the sleeve 91 and the shaft 92 is hindered.
Therefore, when the liquid metal 94 is filled, the liquid metal 94 is filled using the surface tension until it rises in an arc shape from the end surface of the sleeve 91 (see FIG. 5). 94 a is pressed by the lid 93, and the excess liquid metal 94 overflows from between the end surface 91 a of the sleeve 91 and the lid 93, and the lid 93 is attached to the sleeve 91, whereby the end surface 92 a of the shaft 92 and the lid Air is prevented from remaining in the gap between the body 93.
However, in this case, the liquid metal 94 overflowing from the sleeve 91 remains sandwiched between the end surface 91a of the sleeve 91 and the lid 93, and the remaining liquid metal 94 is rotated during the rotation of the shaft 92 and the like. Leakage from the mating surfaces will contaminate the atmosphere around the bearing device. 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.
[0004]
Further, the operation of filling the liquid metal 94 and attaching the lid 93 is performed in an atmosphere containing nitrogen gas or argon gas in order to prevent the liquid metal 94 from being oxidized. For this reason, a part of these oxidation-preventing gases are mixed or dissolved in the liquid metal 94, and this mixed or dissolved gas is moved between the end surface 92a of the shaft 92 and the lid 93 during the rotation of the shaft 92 or the like (thrust The lubricating film is not easily formed by the liquid metal 94. As a result, there is a problem that the lubrication failure of the thrust part occurs and the rotational performance is deteriorated.
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 the atmosphere from being contaminated and the rotational performance from being deteriorated.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the sliding bearing device of the present invention closes one end of a cylindrical sleeve with a lid, introduces the shaft into the sleeve so as to be relatively rotatable, and the shaft and the sleeve. and the gap between the lid, the sliding bearing device is filled with a liquid metal for lubrication, the portion facing the end face of the shaft of the upper Kifutatai, a recess for storing the liquid metal, this A through hole is formed in communication with the recess to allow excess liquid metal to leak out of the sleeve, and the through hole is closed with a stopper, and the recess gradually reduces in diameter toward the through hole. And the said recessed part and through-hole are provided concentrically with the axis | shaft (Claim 1).
[0006]
According to the sliding bearing device having the above-described configuration, when the lid is attached to the sleeve, excess liquid metal overflows to the outside through the through hole of the lid instead of the mating surface of the sleeve and the lid. . For this reason, it is possible to prevent the liquid metal from remaining on the mating surface of the sleeve and the lid.
Further, even when the antioxidant gas mixed or dissolved in the liquid metal moves between the shaft and the lid, the antioxidant gas can be stored in the recess together with the liquid metal. For this reason, it can prevent that lubrication performance falls with the said gas for antioxidant.
Furthermore, by heating the slide bearing device, the gas mixed in or dissolved in the liquid metal can be exhausted through a minute gap formed between the through hole and the plug.
[0007]
Said recess towards the through hole than is gradually reduced in diameter, when attaching the lid to the sleeve, the ambient gas is interposed between the lid and the liquid metal, all the through-hole by the recess Can be guided and exhausted. As a result, atmospheric gas can be prevented from remaining in the recess.
[0008]
Furthermore, the recess and the through hole, than is provided in the shaft concentrically, when attaching the lid to the sleeve, the excess liquid metal can lead to equally from the periphery of the recess to the through hole. As a result , it is possible to effectively prevent excess liquid metal pressed by the lid from flowing toward the mating surface between the sleeve and the lid.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of an essential part showing a fluid dynamic bearing device according to one embodiment of the present invention. In the figure, the hydrodynamic bearing device includes a cylindrical sleeve 1, a lid body 2 that closes one end of the sleeve 1, and a shaft 3 that is introduced into the sleeve 1 with a minute gap. The main part is constituted by the shaft 3 and the liquid metal 4 for lubrication filled between the sleeve 1 and the lid 2.
[0010]
The lid 2 is disk-shaped, and is screwed to the end surface 1 a of the sleeve 1 after the sleeve 1 is filled with the liquid metal 4. A concave portion 5 that stores the liquid metal 4 and a through hole 6 that leads from the bottom of the concave portion 5 to the outside of the bearing are formed in a portion of the lid body 2 that faces the end surface 3 b of the shaft 3. The plug 7 is closed.
The recess 5 and the through hole 6 are provided concentrically with the axis of the shaft 3. In addition, the inner wall of the recess 5 is formed by a conical surface that gradually decreases in diameter toward the through hole 6.
The plug 7 is made of resin or metal and is screwed into the through hole 6. As the liquid metal 4, gallium, mercury, sodium or the like is used.
[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]
With the above configuration, when assembling the hydrodynamic bearing device, the liquid metal 4 is filled from the end surface 1a of the sleeve 1 until it rises in an arc shape (see FIG. 2), and the through hole 6 is not attached without the plug 7 being attached. When the lid 2 with the opening opened is attached to the sleeve 1, the portion 4a of the liquid metal 4 raised from the end surface 1a of the sleeve 1 in an arc shape can be introduced into the recess 5 of the lid 2 and the surplus The liquid metal 4 can be overflowed to the outside of the bearing through the through hole 6 of the lid 2. For this reason, it is possible to prevent excess liquid metal 4 from entering and remaining on the mating surface between the end surface 1 a of the sleeve 1 and the lid 2. Therefore, it is possible to prevent the conventional disadvantage that the liquid metal 4 remaining on the mating surface leaks during the relative rotation between the sleeve 1 and the shaft 3 and the surrounding atmosphere is contaminated.
[0013]
Further, even when the oxidation preventing gas mixed or dissolved in the liquid metal 4 moves between the shaft 3 and the lid 2, the oxidation preventing gas is stored in the recess 5 together with the liquid metal 4. I can leave. For this reason, it can prevent that lubrication performance falls with the said gas for antioxidant.
Further, since the inner wall of the recess 5 of the lid 2 is a conical surface that gradually decreases in diameter toward the through hole 6, the lid 2 is attached between the liquid metal 4 and the lid 2 when the lid 2 is attached to the sleeve 1. All of the intervening atmospheric gas can be guided to the through hole 6 by the conical surface and exhausted. For this reason, it is possible to prevent the atmospheric gas from remaining in the concave portion 5 and, in turn, to prevent the lubrication performance of the thrust portion from being deteriorated due to a large amount of atmospheric gas remaining in the concave portion 5. it can. On the other hand, when the inner wall of the recess 5 is a circumferential surface where the generatrix extends parallel to the axis of the shaft 3, when the lid 2 is attached to the sleeve 1, Atmospheric gas easily accumulates between the metal 4 (see FIG. 3).
[0014]
Moreover, since the said recessed part 5 and the through-hole 6 are provided concentric with the axis | shaft 2, the excess liquid metal 4 can be uniformly introduced into the through-hole from the circumference | surroundings of the recessed part 5, and can be efficiently leaked. For this reason, it is possible to effectively prevent the excess liquid metal 4 pressed by the lid body 2 from flowing toward the mating surface between the sleeve 1 and the lid body 2. It is possible to more reliably prevent excess liquid metal 4 from entering and remaining on the mating surfaces. Further, when the sleeve 1 is used as the rotation side, the rotation balance of the sleeve 1 can be ensured.
The hydrodynamic bearing device penetrates the antioxidation gas mixed or dissolved in the liquid metal 4 by heating to a temperature (for example, 300 ° C.) higher than its operating temperature (for example, 250 ° C.). It is also possible to evacuate through a minute gap formed between the hole 6 and the plug 7.
[0015]
The through-hole 6 of the lid 2 is not necessarily provided concentrically with the shaft 3 as long as it communicates with the recess 5. For example, the through-hole 6 extends in the radial direction of the lid 2 and opens to the peripheral surface. Good.
Further, the present invention can be applied not only to the above-described dynamic pressure bearing device but also to a sliding bearing in which the shaft 3 does not have a groove 3a for generating radial dynamic pressure.
[0016]
【The invention's effect】
As described above, according to the sliding bearing device of the present invention, when attaching the lid to the sleeve, excess liquid metal can be leaked to the outside through the through hole of the lid, so the sleeve and the lid It is possible to prevent the liquid metal from remaining on the mating surface. For this reason, it is possible to prevent the disadvantage that the liquid metal remaining on the mating surface leaks and the surrounding atmosphere is contaminated during the rotation of the shaft or the sleeve.
Further, even when the antioxidant gas mixed or dissolved in the liquid metal moves between the shaft and the lid, the antioxidant gas can be stored in the recess together with the liquid metal. For this reason, it can prevent that lubrication performance falls with the said gas for antioxidant.
[0017]
Furthermore , since the concave portion is gradually reduced in diameter toward the through hole, it is possible to prevent the atmospheric gas from remaining in the concave portion, so that the lubricating performance of the thrust portion can be achieved by the residual atmospheric gas. Can be prevented from decreasing.
In addition, since the recess and the through hole are provided concentrically with the shaft, excess liquid metal pressed by the cover when the cover is attached to the sleeve is uniformly introduced from the periphery of the recess into the through hole. Thus, it is possible to effectively prevent the liquid metal from flowing toward the mating surface of the sleeve and the lid, so that excess liquid metal enters and remains on the mating surface of the sleeve and the lid. It can prevent more reliably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a fluid dynamic bearing device according to one embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part showing an assembly process.
FIG. 3 is an enlarged cross-sectional view of a main part showing another embodiment.
FIG. 4 is a cross-sectional view of a main part showing a conventional example.
FIG. 5 is a cross-sectional view of a main part showing an assembly process of a conventional example.
[Explanation of symbols]
1 Sleeve 2 Lid 3 Shaft 4 Liquid Metal 5 Recess 6 Through Hole 7 Plug

Claims (1)

One end of the cylindrical sleeve is closed with a lid, the shaft is introduced into the sleeve so as to be relatively rotatable, and a liquid metal for lubrication is provided in a gap between the shaft and the sleeve and the lid. In the sliding bearing device filled with
In the portion facing the end surface of the lid shaft, a recess for storing the liquid metal is formed, and a through hole is formed in communication with the recess to allow excess liquid metal to leak out of the sleeve. A sliding bearing device, wherein the through hole is closed with a stopper , the concave portion is gradually reduced in diameter toward the through hole, and the concave portion and the through hole are provided concentrically with the shaft .

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