JP2002106564A - Porous static pressure gas bearing and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous static pressure gas bearing capable of conducting sealing treatment without using a sealant, of obtaining the desired dimensional accuracy of a porous metallic sintered compact, of maintaining stable sealing over a long time, of substantially shortening the working time for sealing and of providing sealing to required area only, and its manufacturing method. SOLUTION: A porous static pressure gas bearing 1 is provided with a porous metallic sintered compact 2 and a housing 3 inside which the porous metallic sintered compact is fitted. In the porous metallic sintered compact 2, the cylindrical inner peripheral surface as a radial bearing surface 4 contains a plurality of openings 6 of a pore 5, a metallic part 7, and a mineral part 8. Other than the radial bearing surface 4, both annular end surfaces 10 and 11 exposed to the outside of the porous metallic sintered compact 2 contains a metallic part 12 and the spreading part 13 of the metallic part 12. The openings 6 of the pore 5 on the end surfaces 10 and 11 are stopped up with the spreading part 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous hydrostatic gas bearing using a porous metal sintered body and a method of manufacturing the same.

[0002]

A porous hydrostatic gas bearing has been attracting attention as a material having excellent high-speed stability and a high load capacity, and various studies have been made. There are several issues to overcome.

[0003] When a porous metal sintered body is used for a porous static pressure gas bearing, a sealing process is usually applied to portions other than the bearing surface so that the supplied high-pressure gas is not wasted. You.

[0004] Such a sealing treatment is usually performed by applying a sealing agent made of a silicone resin or the like to the surface of the porous metal sintered body, but is applied and formed on the surface of the porous metal sintered body. The sealing agent layer for sealing requires a certain thickness to receive wind pressure from a high-pressure gas, which affects the dimensional accuracy of the porous metal sintered body and also reduces the porous metal sintered body. There is also a risk of peeling off from the surface of the substrate.

[0005] The sealing treatment with a sealant requires a drying step after coating, and also causes the sealant to flow to the other surface of the porous metal sintered body formed as a bearing surface. There is also a risk of flowing out, it takes a long time to work, and it becomes a complicated process, and further, the sealing agent soaks into the pores of the porous metal sintered body,
There is also a possibility that necessary pores may be sealed.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to perform a sealing treatment without using a sealant made of a silicone resin or the like. Dimensional accuracy of the high quality metal sintered body can be obtained as desired, stable sealing can be maintained for a long time, and complicated steps can be eliminated, and the sealing work time can be greatly reduced. An object of the present invention is to provide a porous hydrostatic gas bearing capable of performing only sealing and a method of manufacturing the same.

[0007]

The porous hydrostatic gas bearing according to the first aspect of the present invention includes a porous metal sintered body, wherein the bearing surface of the porous metal sintered body is Has a metal part, an inorganic part, and a large number of pore openings that are mixed randomly, and other than the bearing surface, the surface exposed to the outside of the porous metal sintered body is a metal part, A metal portion, and the opening of at least most of the pores on the surface exposed to the outside is closed by the spread portion.

[0008] According to the porous hydrostatic gas bearing of the first aspect, the opening of at least most of the pores of the surface other than the bearing surface and exposed to the outside of the porous metal sintered body is expanded by the metal portion. Because it is closed by the extension, it is possible to eliminate gas emission from this exposed surface, to avoid wasteful consumption of the supplied high-pressure gas, and to seal the pores with the extension of the metal part. As a result, it is possible to maintain a stable sealing over a long period of time as compared with the sealing agent, and there is no overhang from the exposed surface, and the dimensional accuracy of the porous metal sintered body can be obtained as desired. Can be

In the porous hydrostatic gas bearing according to the first aspect, the openings of the pores on the surface exposed to the outside are closed by metal parts other than the extending part, whereby the parts are exposed to the outside. The surface is made so that there are almost no pore openings.

According to the present invention, as in the porous hydrostatic gas bearing of the second aspect, the bearing surface further includes a metal portion extending portion, and the metal portion of the bearing surface extends. In the porous hydrostatic gas bearing according to the third aspect of the present invention, the extension narrows at least a part of the multiple openings in the bearing surface.

According to the porous static pressure gas bearing of the third aspect, since the opening of a part of the pores on the bearing surface is narrowed by the extending portion, the pores are largely opened directly on the bearing surface. Self-excited vibration (pneumatic hammer phenomenon)
And a stable bearing function can be exhibited.

[0012] In the second aspect of the present invention, the extended portion of the metal portion of the bearing surface is, like the porous hydrostatic gas bearing of the fourth aspect of the present invention, one of a large number of openings in the bearing surface. The opening of the portion may be closed, or may be separated by an inorganic portion as in the porous hydrostatic gas bearing according to the fifth aspect of the present invention.

The porous metal sintered body of the porous static pressure gas bearing according to the sixth aspect of the present invention has a cylindrical shape and an annular end face exposed to the outside. The porous static pressure gas bearing according to the seventh aspect of the present invention has a cylindrical shape, is fitted in the housing, and has an annular end face exposed to the outside.

According to the porous static pressure gas bearing of the sixth aspect, a radial bearing can be constituted by using the outer peripheral surface or the inner peripheral surface of the porous metal sintered body as the bearing surface, According to the porous hydrostatic gas bearing, the housing can seal the outer peripheral surface of the porous metal sintered body, and gas is wasted from the opening on the outer peripheral surface of the pores of the porous metal sintered body. It can eliminate spurting.

In the porous static pressure gas bearing according to the eighth aspect of the present invention, the porous metal sintered body has a rectangular shape and a rectangular end face exposed to the outside. Yes,
In the porous static pressure gas bearing of the ninth aspect of the present invention, it has a rectangular shape and is fixed to a plate-shaped backing metal,
It has a rectangular end face exposed to the outside.

The porous static pressure gas bearing according to the present invention may be constituted by the porous metal sintered body itself using the porous metal sintered body naked, but as in the seventh embodiment described above, The outer peripheral surface of the porous metal sintered body may be covered with a housing, and may be composed of a porous metal sintered body and a housing.
As in the ninth embodiment, the porous metal sintered body may be fixed to the plate-shaped backing metal, and may be constituted by such a plate-shaped backing metal and a porous metal sintered body. The porous hydrostatic gas bearing of the present invention can be used as a bearing for a linear member such as a slider.

In the porous static pressure gas bearing according to the tenth aspect of the present invention, in the porous static pressure gas bearing according to any one of the first to ninth aspects, the metal parts of the bearing surface and the surface exposed to the outside are provided. And at least tin, phosphorus and copper, and the inorganic portion of the bearing surface contains at least one of graphite, boron nitride, graphite fluoride, calcium fluoride, aluminum oxide, silicon oxide and silicon carbide. In the porous static pressure gas bearing according to the eleventh aspect of the present invention, in the porous static pressure gas bearing according to the tenth aspect, the metal part of the bearing surface and the surface exposed to the outside further comprises nickel or manganese. Contains.

According to the porous hydrostatic gas bearing of the tenth aspect, it is possible to provide a preferable spreadable portion because the metal portion of the bearing surface and the surface exposed to the outside contains metal excellent in spreadability, Further, in the porous static pressure gas bearing of the tenth aspect,
When the inorganic portion of the bearing surface contains at least one of graphite, boron nitride, graphite fluoride and calcium fluoride, these functions as a solid lubricant and are supported by the porous hydrostatic gas bearing. Even when the rotating shaft or the slider comes into contact with each other at the time of standstill or start-up, these components are hardly damaged and a fail-safe porous hydrostatic gas bearing is obtained.

In the method of manufacturing a porous static pressure gas bearing according to the first aspect of the present invention, a cylindrical powder portion containing a metal powder and an inorganic powder is disposed on both end surfaces of the cylindrical powder portion. And a preparation step of preparing a green compact integrally having an annular green compact portion mainly containing a metal powder, and a porous step of sintering the green compact to produce a cylindrical porous metal sintered body. A porous metal sintered body manufacturing process, and grinding the porous metal sintered body,
A grinding step of forming a bearing surface on a cylindrical surface of the porous metal sintered body and forming a surface exposed to the outside on an end surface of the porous metal sintered body.

According to the manufacturing method of the first aspect, the porous metal sintered body is ground to form a surface exposed to the outside at the end face of the porous metal sintered body. The metal part of the end face made of the powder is subjected to plastic deformation by grinding to close the openings of the pores on the exposed surface. As a result, the sealing process can be performed without using a sealant made of silicone resin or the like. As a result, the dimensional accuracy of the porous metal sintered body can be obtained as desired, a stable sealing can be maintained for a long time, and a complicated process can be eliminated, thereby greatly reducing the sealing work time. The sealing can be performed only where necessary.

The method of manufacturing a porous hydrostatic gas bearing according to the second aspect of the present invention comprises the steps of disposing a thick cylindrical green compact mainly containing metal powder and an inner peripheral surface of the thick cylindrical green compact. And a preparing step of preparing a combined compact having a thin cylindrical compact including metal powder and inorganic powder, and sintering the combined compact to form a thick cylindrical compact. Metal-sintered body manufacturing step of manufacturing a cylindrical porous metal sintered body formed by integrating a body and a thin-walled cylindrical green compact, and grinding the porous metal sintered body to form a porous metal sintered body. Forming a bearing surface on the cylindrical surface of the porous metal sintered body and forming a surface exposed to the outside on the end surface of the porous metal sintered body.

According to the manufacturing method of the second embodiment, the metal powder is mainly ground by grinding the porous metal sintered body to form a surface exposed to the outside at the end face of the porous metal sintered body. As a result of causing plastic deformation by grinding on the metal portion at the end face which is mostly from the thick cylindrical green compact containing, as a result of being able to close the opening of the pores on the exposed surface, the manufacturing method of the first aspect and Similar effects can be produced.

The method of manufacturing a porous hydrostatic gas bearing according to the third aspect of the present invention comprises the steps of providing a green compact for a bearing surface containing a metal powder and an inorganic powder and a green compact for an end surface mainly containing a metal powder. Preparing step and preparing the green compact for the bearing surface at the site to be the bearing surface, and arranging the green compact for the end surface at the site other than the bearing surface and the surface to be exposed to the outside , A composite body manufacturing step of manufacturing these combined bodies, and sintering the manufactured combined body to form a porous metal sintered body by integrating a green compact for a bearing surface and a green compact for an end face. A porous metal sintered body manufacturing step of manufacturing a body, and grinding the porous metal sintered body to form a bearing surface at a portion formed of a green compact for a bearing surface, and forming a green compact for an end surface. A grinding step of forming a surface exposed to the outside at a site formed by the body.

According to the manufacturing method of the third aspect, the porous metal sintered body is ground to form a surface exposed to the outside at a portion formed mainly by the end compact including the metal powder. Then, plastic deformation is caused by grinding the metal portion on the exposed surface, and the opening of the pores on the exposed surface is closed. As a result, the same effect as the manufacturing method of the first and second aspects is obtained. Can be caused.

In the manufacturing method according to the fourth aspect of the present invention, in the above manufacturing method, the metal powder contains at least tin, phosphorus and copper, and the inorganic powder is graphite, boron nitride,
It contains at least one of graphite fluoride, calcium fluoride, aluminum oxide, silicon oxide and silicon carbide.

According to the manufacturing method of the fourth aspect, since the sintered portion made of the metal powder exhibits excellent ductility, the opening of the pore can be reliably closed on the surface exposed to the outside,
On the bearing surface, irrespective of the excellent ductility of the sintered part made of metal powder, even if the sintered part made of metal powder is plastically deformed to close the opening of the pore, the brittle inorganic part will cause The plastic flow of the sintered part is cut off, and the closure of the opening of the pores is preferably suppressed. Thus, even after the formation of the bearing surface, an ideal drawing structure in which the clogging of the pores was suppressed was obtained. A porous hydrostatic gas bearing having fine pores can be obtained, and further, when at least one of graphite, boron nitride, graphite fluoride and calcium fluoride is contained as the inorganic powder, these are solid lubricants. As a result, even if the rotating shaft or the slider supported by the porous hydrostatic gas bearing comes into contact with each other when the rotary shaft or the slider comes to rest or starts, a failure-prone porous hydrostatic gas bearing can be obtained.

When the metal powder further contains nickel or manganese as in the manufacturing method according to the fifth aspect of the present invention, the rigidity of the sintered portion made of the metal powder can be appropriately increased.

Further, as in the manufacturing method according to the sixth aspect of the present invention, the method may further include a fitting step of fitting and fixing the porous metal sintered body in the housing.

According to the manufacturing method of the sixth aspect, it is possible to manufacture a porous hydrostatic gas bearing which is reinforced by the housing and one of the surfaces of the porous metal sintered body can be sealed with the housing.

The metal powder for forming the porous metal sintered body preferably has a particle diameter of 30 μm to 150 μm, and more preferably 45 μm to 75 μm. From 30 μm to 3
00 μm, preferably 45 μm to 150 μm
The sintering density and porosity of a porous metal sintered body using such a metal powder and an inorganic powder are different depending on the sintering time and the sintering temperature.
A pressure of from 7 cm / cm ² to 7 ton / cm ² is applied to form a green compact, and this green compact is 800
In the case of sintering at a temperature of from 1 ° C. to 1150 ° C. for 20 to 60 minutes, the sintering density is generally 5.15 g / cm ^{3 to} 6.19 g / cm ³ and the porosity is 21.1% to 34.1.
% (In terms of oil content).

In the method of the present invention, the machining of the porous metal sintered body is often performed by grinding after turning. It is preferable that the machining allowance in this grinding is performed within a range of about 0.2 mm or less.

Hereinafter, the present invention and embodiments of the present invention will be described.
A description will be given based on a preferred example with reference to the drawings. Note that the present invention is not limited to these examples.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 4, a porous hydrostatic gas bearing 1 of the present embodiment has a cylindrical porous metal sintered body 2 having a cylindrical shape.
And a metal rigid housing 3 which is also cylindrical and has a porous metal sintered body 2 fitted therein.

In the porous metal sintered body 2 having a cylindrical shape, the cylindrical inner peripheral surface 4 as a radial bearing surface is provided with openings 6 of a large number of fine holes 5 mixed randomly and a metal portion 7.
, An inorganic portion 8 and a spread portion 9 of the metal portion 7, a surface other than the inner peripheral surface 4 and exposed to the outside of the porous metal sintered body 2, in this example, annular both ends Surfaces 10 and 11 are
It has a metal part 12 and a spread part 13 of the metal part 12, and the openings of the pores 5 on both end faces 10 and 11 are
It is blocked by 3.

The extending portion 9 of the metal portion 7 on the inner peripheral surface 4
Are composed of an aperture 6 that is squeezed, an aperture that blocks the aperture 6, and an aperture that is divided by an inorganic portion 8.

As the surfaces exposed to the outside, annular end surfaces 10
In the porous metal sintered body 2 having the steps (a) and (b), an annular recess 22 is formed in a cylindrical outer peripheral surface 21;
The annular recess 22 covered by the cylindrical inner peripheral surface 23 of the housing 3 forms an annular supply passage 24 that supplies gas, in this example, high-pressure air, to the pores 5 of the porous metal sintered body 2. I have.

The housing 3 has a threaded through-hole 25 communicating with the annular supply passage 24 and an air supply plug is mounted in the through-hole 25. Since the inner peripheral surface 23 of the housing 3 is in close contact with the outer peripheral surface 21 of the porous metal sintered body 2, the opening of the pore 5 of the porous metal sintered body 2 on the outer peripheral surface 21 is sealed. Have been. In order to complete the sealing process on the outer peripheral surface 21, a seal made of silicone resin or the like is provided between the inner peripheral surface 23 of the housing 3 and the outer peripheral surface 21 of the porous metal sintered body 2. A blocking agent may be interposed.

In this example, the metal portions 7 and 12 of the inner peripheral surface 4 and both end surfaces 10 and 11 contain tin, phosphorus, nickel and copper, and the inorganic portion 8 of the inner peripheral surface 4 contains graphite. In.

In the above-described porous hydrostatic gas bearing 1, the high-pressure air supplied to the through-hole 25 is supplied to the annular supply passage 24, and the high-pressure air supplied to the annular supply passage 24 is supplied to the porous metal sintered body. The high-pressure air film is ejected from the inner peripheral surface 4 through the pores 5 of the body 2 to form a high-pressure air film between the inner peripheral surface 4 and the outer peripheral surface of the rotating shaft 31. Hydrostatic gas bearing 1
Supports the rotating shaft 31 rotatably in the radial direction.

According to the porous static pressure gas bearing 1, the inner peripheral surface 4
Since the openings of the pores 5 of the end faces 10 and 11 exposed to the outside of the porous metal sintered body 2 are closed by the extending portions 13 of the metal portion 12, the end faces 10 and 11 Can be eliminated, the wasteful consumption of the supplied high-pressure air can be eliminated, and the sealing of the pores 5 is made by the extending portion 13 of the metal portion 12, so that the sealing agent is not used. As a result, stable sealing can be maintained for a long period of time, and there is no overhang from both end faces 10 and 11, so that the dimensional accuracy of the porous metal sintered body 2 can be obtained as desired.

According to the porous hydrostatic gas bearing 1, since the opening 6 of a part of the pores 5 on the inner peripheral surface 4 is narrowed by the extending portion 9, many pores 5 are Self-excited vibration (pneumatic hammer phenomenon) caused by the large opening in the surface 4 can be eliminated, a stable bearing function can be exhibited, and the housing 3 seals the outer peripheral surface 21 of the porous metal sintered body 2. The porous metal sintered body 2 can be subjected to a hole treatment.
Unnecessary gas can be prevented from being ejected from the opening of the outer peripheral surface 21 of the fine pore 5.

Next, an example of a method for manufacturing the above-described porous hydrostatic gas bearing 1 will be described. First, as shown in FIG. 5, an outer mold 28 having a cylindrical inner peripheral surface 27 and a lower mold 26 having a small-diameter cylindrical portion 29 and a large-diameter cylindrical portion 30 as a core are prepared. In the cylindrical hollow portion 32 formed by the outer mold 28 and the lower mold 26, for example, a mixed metal powder composed of 4% to 10% of tin, 10% to 40% of nickel, 0.5% to 4% of phosphorus, and the balance of copper is used. Then, by mixing and depositing a mixed metal powder containing no inorganic powder such as graphite, boron nitride, graphite graphite, calcium fluoride, aluminum oxide, silicon oxide and silicon carbide, the annular thin mixed powder layer 33 is formed. After the formation and the formation of the mixed powder layer 33, the cylindrical hollow portion 32 is similarly filled with tin 4% to 10%, nickel 10% to 40%, phosphorus 0.5% to 4%, and graphite 3% to 10% by weight. Metal powder consisting of By mixing and depositing a mixed powder with an inorganic powder containing at least one of boron nitride, graphite fluoride, calcium fluoride, aluminum oxide, silicon oxide and silicon carbide, a thick cylindrical mixed powder layer 34 is formed. After the formation of the mixed powder layer 34, an annular thin mixed powder layer 35 of mainly mixed metal powder similar to the mixed powder layer 33 is formed in the same manner.

Next, a cylindrical upper die 37 having a cylindrical inner portion 36 into which the small-diameter cylindrical portion 29 as shown in FIG.
While pressing the upper mold 37 toward the lower mold 26, and inserting the mixed powder layers 33, 3
A pressure of ² to 7 ton / cm ² is applied to 4 and 35 to form a cylindrical compacted portion 38 comprising a mixed powder layer 34.
And a powder compact 52 composed of mixed powder layers 33 and 35 and integrally having annular powder compacts 39 and 40 disposed on both end surfaces of the cylindrical compact compact 38, and after compacting, The green compact 52 is obtained by taking it out of the mold.

The green compact 52 thus prepared is machined to form an annular recess 22 as shown in FIG. 7, and the green compact 52 having the annular recess 22 formed therein is placed in a reducing atmosphere or vacuum. Sintering is performed at a temperature of 800 ° C. to 1150 ° C. for 20 minutes to 60 minutes to produce a cylindrical porous metal sintered body 2 having an annular recess 22 as shown in FIG.

After the production of the porous metal sintered body 2, the inner peripheral surface 4, which is the cylindrical surface of the porous metal sintered body 2, is turned. The peripheral surface 4 is formed as a bearing surface, and the annular end faces 10 and 11 of the porous metal sintered body 2 are appropriately turned so that a sufficient extended portion 13 of the metal portion 12 is formed on the end faces 10 and 11. hand,
After the turning, the end faces 10 and 11 are formed as surfaces that are exposed to the outside. The machining allowance for grinding the inner peripheral surface 4 and the end surfaces 10 and 11 is approximately 0.2.
mm or less.

After these grinding steps, as shown in FIG.
The porous metal sintered body 2 is inserted into a through hole 25
By fitting and fixing in the cylindrical housing 3 having the above, the porous hydrostatic gas bearing 1 as shown in FIGS. 1 and 2 can be obtained.

According to the manufacturing method described above, the porous hydrostatic gas bearing 1 having the above-mentioned features can be obtained, and the porous metal sintered body 2 is ground to form the porous metal sintered body. Body 2
In order to form the surfaces exposed to the outside on the end surfaces 10 and 11, the metal portions 12 of the end surfaces 10 and 11 mainly made of metal powder are plastically deformed to open the pores 5 of the exposed end surfaces 10 and 11. As a result, the sealing treatment can be performed without using a sealing agent made of a silicone resin or the like, and thus the dimensional accuracy of the porous metal sintered body 2 can be obtained as desired, and the porous metal sintered body 2 can be stably maintained for a long time. Sealing can be maintained, and the complicated steps can be eliminated to greatly reduce the sealing work time.
Sealing can be performed only where necessary.

According to the above-described manufacturing method, the metal portion 7
And 12 exhibit excellent spreadability, so that the openings of the pores 5 can be reliably closed at the end faces 10 and 11, while the metal portion 7 is formed on the inner peripheral surface 4 irrespective of the excellent spreadability of the metal portion 7. Is plastically deformed and tries to close the opening 6 of the pore 5,
The plastic flow of the metal part 7 is divided by the brittle inorganic part 8, and the closure of the opening 6 of the pore 5 is preferably suppressed.
Even after the formation of the bearing surface composed of the inner peripheral surface 4, it is possible to obtain the porous hydrostatic gas bearing 1 having the pores 5 having an ideal aperture structure in which the clogging of the pores 5 is suppressed, Further, when at least one of graphite, boron nitride, graphite fluoride, and calcium fluoride is contained as the inorganic powder, they function as a solid lubricant, and are supported by the porous hydrostatic gas bearing 1. Even when the rotating shaft 31 comes into contact with the stationary shaft or at the time of starting, the damping hardly occurs in the rotating shaft 31 and the fail-safe porous hydrostatic gas bearing 1 is obtained.

Further, according to the above-described manufacturing method, the outer peripheral surface 2 of the porous metal sintered body 2 is reinforced by the housing 3.
The porous static pressure gas bearing 1 in which the housing 1 can be sealed with the housing 3 can be manufactured.

The porous hydrostatic gas bearing 1 may be manufactured as follows. That is, for example, as shown in FIG.
And 10% of nickel, 10% to 40% of nickel, 0.5% to 4% of phosphorus, and the balance of copper. It is densely arranged on the inner peripheral surface 62 and has a weight ratio of tin of 4% to 1%.
0%, nickel 10% to 40%, phosphorus 0.5% to 4
%, Graphite 3% to 10%, and a thin green compact 63 containing a metal powder and an inorganic powder consisting of a balance of copper.

The thick cylindrical green compact 61 and the thin cylindrical green compact 63 are prepared by arranging a metal powder and a mixed powder of a metal powder and an inorganic powder in a mold, from 2 tons / cm ² to 7 tons. / pressure of cm ² was added be made by molding, combined green compact 64 is produced by fitting a thin-walled cylindrical green compact 63 in the interior of the thick cylindrical green compact 61.

Next, on the cylindrical outer peripheral surface 65 of the combined green compact 64, in this example, as shown in FIG. 10, two annular recesses 22a and 22b and these annular recesses 22a and 22b are formed.
A communication groove 66 for communicating b is formed by machining.

The annular recesses 22a and 2 thus prepared are
2b and the combined green compact 64 having the communication groove 66 are sintered in the same manner as described above, and the thick cylindrical green compact 61 and the thin cylindrical green compact 63 are integrated, as shown in FIG. A cylindrical porous metal sintered body 2 is produced, and the porous metal sintered body 2 is subjected to turning and grinding in the same manner as described above, and a bearing surface is formed on the cylindrical surface 4 of the porous metal sintered body 2. The surface exposed to the outside is formed on the end faces 10 and 11 of the porous metal sintered body 2. After the grinding step, as shown in FIG. 11, the porous metal sintered body 2 is fitted and fixed in a cylindrical housing 3 having a through-hole 25 that has been threaded in advance in the same manner as described above. 1 and 2 can be obtained.

The porous hydrostatic gas bearing 1 manufactured according to this embodiment has two annular supply passages 24 formed by annular recesses 22a and 22b.
4 is communicated with the through hole 25 via the communication groove 66. The number of the communication grooves 66 for connecting the annular recesses 22a and 22b to each other is not limited to one, but may be two or more.

According to the manufacturing method shown in FIGS. 9 to 11,
In order to form a surface exposed to the outside on the end faces 10 and 11 of the porous metal sintered body 2 by subjecting the porous metal sintered body 2 to grinding processing, a thick cylindrical green compact mainly containing metal powder 6
As a result of causing plastic deformation in the metal portion 12 of the end faces 10 and 11 which are mostly made of the sintered body 1 and closing the openings of the pores 5 on the exposed surface, the same effect as in the previous manufacturing method is produced. Can be done.

Further, the porous hydrostatic gas bearing 1 may be manufactured as follows. That is, as shown in FIG. 12, for example, a cylindrical green compact 41 for a bearing surface containing a metal powder containing tin, phosphorus, nickel and copper and an inorganic powder containing graphite.
For example, tin 4% to 10%, nickel 10% to 40
As shown in FIG. 13, two annular green compacts 42 each containing a metal powder consisting of 0.5% to 4% of phosphorus, 0.5% to 4% of phosphorus and the balance of copper are prepared.

Next, as shown in FIG. 14, the compacts 42 are arranged on both end surfaces of the compact 41, that is, the compacts 41 are arranged at the portions to be the bearing surfaces. Are disposed on a portion other than the bearing surface and become a surface exposed to the outside, and a combined body 43 of these is manufactured. When manufacturing the combination body 43, the green compact 42 is brought into close contact with both end surfaces of the green compact 41 using an appropriate jig, and the inner peripheral surfaces thereof are flush with each other.

The thus-prepared combination 43 is subjected to a heating at 800 ° C. to 1150 ° C. in a reducing atmosphere or vacuum.
After sintering for 0 to 60 minutes, the green compact 41 and the green compact 42 are integrated with each other at their contact surfaces to form an integrated body having an annular recess 22 on the outer peripheral surface 21 as shown in FIG. Is produced.

After the production of the porous metal sintered body 2, the cylindrical inner peripheral surface 4 of the porous metal sintered body 2 is turned, and after the turning processing, the inner peripheral surface of the porous metal sintered body 2 is ground by grinding. The surface 4 is formed as a bearing surface, and the annular end surfaces 10 and 11 of the porous metal sintered body 2 are formed.
With sufficient metal parts 12 at the end faces 10 and 11
Turning is performed appropriately so that the extended portion 13 is generated, and after the turning, the grinding is performed to form the end surfaces 10 and 11 as surfaces exposed to the outside. The machining allowance in the grinding of the inner peripheral surface 4 and the end surfaces 10 and 11 is preferably approximately within a range of 0.2 mm or less.

After these grinding steps, as shown in FIG. 16, the porous metal sintered body 2 is fitted and fixed in a cylindrical housing 3 having a through-hole 25 which has been threaded in advance. 1 and 2 can be obtained.

According to the above-described manufacturing method, the porous hydrostatic gas bearing 1 having the above-mentioned features can be obtained. In addition, the porous metal sintered body 2 is ground to reduce tin from 4% to 10%. %,
The end faces 10 and 11 which are exposed to the outside are formed in a portion formed by the green compact 42 containing a metal powder composed of 10% to 40% of nickel, 0.5% to 4% of phosphorus and the balance of copper. In (11) and (11), the metal portion 12 is plastically deformed by grinding to close the openings of the fine holes 5 on the end faces 10 and 11, so that the same effect as described above can be obtained.

In the manufacturing method shown in FIGS. 12 to 16, two compacts 42 having an inner diameter equal to the inner diameter of the compact 41 are prepared, and the compact 42 is attached to both end faces of the compact 41. To produce a combined body 43, but instead of this,
Two compacts 4 having an inner diameter equal to the outer diameter of the compact 41
2 and the green compact 42 is arranged on the outer peripheral surface adjacent to both end surfaces of the green compact 41 as shown in FIG. 17 to produce a combined body 51. The porous static pressure gas bearing 1 may be manufactured by firing. Further, a green compact 41 and a green compact 42 having the same inner and outer diameters are prepared, and a recess equivalent to the annular recess 22 is formed on the outer peripheral surface of the green compact 41 by machining. May be produced by arranging the compacts 42 on both end surfaces of the composite body, and firing the combined body in the same manner as described above to produce the porous hydrostatic gas bearing 1.

In the above-described manufacturing method, turning and grinding of the bearing surface 4 and the end surfaces 10 and 11 are performed before fitting and fixing in the housing 3. Bearing surface 4 and end surfaces 10 and 11 after fixation
Turning and grinding may be performed.

The above is the cylindrical porous hydrostatic gas bearing 1.
However, instead of this, a green compact for the bearing surface and the end face of a rectangular shape is prepared, and the green compact for the end face is arranged on the end face of the compact for the bearing face. After preparing these combined bodies, thereafter, firing in the same manner as described above to form a rectangular porous metal sintered body, and fixing the porous metal sintered body to a rectangular backing metal, The entire surface exposed to the outside of the rectangular porous metal sintered body may be ground to manufacture the rectangular porous hydrostatic gas bearing 1. In this case, the fixing of the combination to the back metal may be performed by the firing simultaneously with the firing of the combination.

[0065]

According to the present invention, the sealing treatment can be performed without using a sealing agent made of a silicone resin or the like, and the dimensional accuracy of the porous metal sintered body can be obtained as desired. A porous hydrostatic gas bearing that can maintain stable sealing over a long period of time, can eliminate complicated steps, greatly reduce the time required for sealing work, and can perform sealing only when necessary, and A manufacturing method can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a preferred example of an embodiment of the present invention.

FIG. 2 is a sectional view of the example shown in FIG.

FIG. 3 is an enlarged sectional explanatory view of an inner peripheral surface of the example shown in FIG. 1;

FIG. 4 is an enlarged sectional explanatory view of an end face of the example shown in FIG. 1;

FIG. 5 is an explanatory diagram of an example of the manufacturing method of the example shown in FIG. 1;

FIG. 6 is an explanatory diagram of an example of the manufacturing method of the example shown in FIG. 1;

FIG. 7 is an explanatory diagram of an example of the manufacturing method of the example shown in FIG.

FIG. 8 is an explanatory diagram of an example of the manufacturing method of the example shown in FIG.

FIG. 9 is an explanatory view of another example of the manufacturing method of the example shown in FIG. 1;

FIG. 10 is an explanatory diagram of another example of the manufacturing method of the example shown in FIG. 1;

FIG. 11 is an explanatory diagram of another example of the manufacturing method of the example shown in FIG. 1;

FIG. 12 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

FIG. 13 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

FIG. 14 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

FIG. 15 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

FIG. 16 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

FIG. 17 is an explanatory view of still another example of the manufacturing method of the example shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous static pressure gas bearing 2 Porous metal sintered compact 3 Housing 4 Inner peripheral surface 5 Pores 6 Opening 7,12 Metal part 8 Inorganic part 9,13 Extension part 10,11 End face

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J102 AA02 BA03 BA17 CA15 EA02 FA02 FA09 4K018 AA05 AB01 AB02 AB03 AB07 AC01 FA06 HA03 JA03 KA03 KA22

Claims (17)

[Claims] 1. A porous hydrostatic gas bearing provided with a porous metal sintered body, wherein a bearing surface of the porous metal sintered body has a metal part, an inorganic part, and a large number of pores mixed randomly. The surface other than the bearing surface and exposed to the outside of the porous metal sintered body has a metal portion and an extended portion of the metal portion, and is exposed to the outside. A porous hydrostatic gas bearing in which at least a majority of the openings of the pores on the surface to be closed are closed by an extension. 2. The porous hydrostatic gas bearing according to claim 1, wherein the bearing surface further has an extended portion of a metal portion. 3. The porous hydrostatic gas bearing according to claim 2, wherein the extending portion of the metal portion of the bearing surface narrows at least a part of the plurality of openings of the bearing surface. 4. The porous hydrostatic gas bearing according to claim 2, wherein the extending portion of the metal portion of the bearing surface closes a part of the multiple openings of the bearing surface. 5. The porous hydrostatic gas bearing according to claim 2, wherein the extending portion of the metal portion of the bearing surface is divided by an inorganic portion. 6. The porous static metal according to claim 1, wherein the porous metal sintered body has a cylindrical shape and has an annular end face exposed to the outside. Pressurized gas bearing. 7. The porous metal sintered body according to claim 1, which has a cylindrical shape, is fitted in a housing, and has an annular end surface exposed to the outside. The porous static pressure gas bearing according to claim 1. 8. The porous metal sintered body according to claim 1, wherein the porous metal sintered body has a rectangular shape and a rectangular end face exposed to the outside. Hydrostatic gas bearing. 9. The porous metal sintered body has a rectangular shape, is fixed to a plate-shaped backing metal, and has a rectangular end face exposed to the outside. The porous static pressure gas bearing according to any one of claims 8 to 10. 10. The metal part of the bearing surface and the surface exposed to the outside contains at least tin, phosphorus and copper, and the inorganic part of the bearing surface is graphite, boron nitride, graphite fluoride, calcium fluoride, oxide The porous hydrostatic gas bearing according to any one of claims 1 to 9, comprising at least one of aluminum, silicon oxide, and silicon carbide. 11. The gas bearing according to claim 10, wherein the metal portion of the bearing surface and the surface exposed to the outside further contains nickel or manganese. 12. A cylindrical powder compact containing metal powder and inorganic powder, and an annular powder compact mainly containing metal powder and disposed on both end surfaces of the cylindrical powder compact. A preparing step of preparing a green compact, a step of sintering the green compact to form a cylindrical porous metal sintered body, and a step of preparing a porous metal sintered body. Grinding, forming a bearing surface on the cylindrical surface of the porous metal sintered body, and forming a surface exposed to the outside on the end surface of the porous metal sintered body, the grinding step comprising: Manufacturing method of bearing. 13. A thick cylindrical green compact mainly containing a metal powder, and a thin cylindrical green compact disposed on the inner peripheral surface of the thick cylindrical green compact and containing a metal powder and an inorganic powder. A preparation step of preparing a combined green compact having a body,
Sintering the combined green compact to produce a cylindrical porous metal sintered body obtained by integrating a thick cylindrical green compact and a thin cylindrical green compact. And grinding the porous metal sintered body to form a bearing surface on the cylindrical surface of the porous metal sintered body and to form a surface exposed to the outside on an end surface of the porous metal sintered body. And a method for producing a porous hydrostatic gas bearing. 14. A preparation step of preparing a green compact for a bearing surface containing metal powder and inorganic powder and a green compact for an end surface mainly containing a metal powder; And a composite body forming step of preparing these combined bodies by arranging the green compact for the end surface in a part other than the bearing surface and serving as a surface exposed to the outside, A step of sintering the combined body to form a porous metal sintered body in which a green compact for the bearing surface and a green compact for the end face are integrated; Grinding the sintered body to form a bearing surface at the portion formed of the green compact for the bearing surface and to form a surface exposed to the outside at the portion formed of the green compact for the end surface A method for manufacturing a porous static pressure gas bearing, comprising: 15. The metal powder contains at least tin, phosphorus and copper, and the inorganic powder contains at least one of graphite, boron nitride, graphite fluoride, calcium fluoride, aluminum oxide, silicon oxide and silicon carbide. The method for manufacturing a porous hydrostatic gas bearing according to any one of claims 12 to 14, comprising: 16. The method according to claim 15, wherein the metal powder further contains nickel or manganese. 17. The production of a porous hydrostatic gas bearing according to claim 12, further comprising a fitting step of fitting and fixing the porous metal sintered body in the housing. Method.