JP4461593B2 - Method for producing porous hydrostatic gas bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a porous hydrostatic gas bearing using a porous metal sintered body and a method for producing the same.
[0002]
[Problems to be solved by the invention]
Porous hydrostatic gas bearings have been attracting attention as having excellent high-speed stability and high load capacity, and various studies have been made, but there are some problems to be overcome in practical use.
[0003]
As a porous hydrostatic gas bearing used as a radial and thrust bearing, a cylindrical porous metal sintered body having a radial bearing surface and an annular porous metal sintered body having a thrust bearing surface are provided in a housing. In the case of mounting, a passage for supplying gas to the pores of both porous metal sintered bodies is usually formed in the housing in advance, and this passage forming operation is performed by the inner peripheral surface of the metal rigid housing and Since it has to be performed on the end face, it is a complicated and troublesome operation, which increases the cost. In addition, the gas introduction passages to the inner peripheral surface of the housing and each passage on the end face side are also provided in the housing in advance. This needs to be formed, and this also causes an increase in cost.
[0004]
In addition, after mounting the cylindrical porous metal sintered body in which an annular recess is simply formed on the outer peripheral surface in the housing, the recess is used as a passage for supplying gas to the pores of the porous metal sintered body. In the porous hydrostatic gas bearing to be used, the region where the gas can be supplied to the pores of the porous metal sintered body is limited and narrowed, and in particular, there may be a case where gas ejection functioning as a thrust bearing cannot be obtained as desired. .
[0005]
The present invention has been made in view of the above points, and the object of the present invention is to reduce the cost and widen the region where gas can be supplied to the pores of the porous metal sintered body, It is an object of the present invention to provide a porous static pressure gas bearing that can also achieve gas ejection functioning as a thrust bearing, and a method for manufacturing the same.
[0006]
[Means for Solving the Problems]
The porous static pressure gas bearing according to the first aspect of the present invention includes a porous metal sintered body, and the porous metal sintered body has pores in the porous metal sintered body. A gas supply passage for supplying gas is provided, and the porous metal sintered body has one end opened at the outer peripheral surface of the porous metal sintered body and the other end opened at the gas supply passage. A gas introduction passage for introducing gas into the passage is provided.
[0007]
According to the porous hydrostatic gas bearing of the first aspect, since the gas supply passage is provided inside the porous metal sintered body, the entire area around the gas supply passage is made of the porous metal sintered body. It can be used as a gas supply area to the pores, and thus the area where gas can be supplied to the pores of the porous metal sintered body can be widened, and the gas jet functioning as a thrust bearing can be made desired. Further, when a porous hydrostatic gas bearing comprising such a porous metal sintered body and a housing fitted with the porous metal sintered body is configured, a gas supply passage is provided in the housing in advance. There is no need to form it, and therefore the cost can be sufficiently reduced.
[0008]
In the porous hydrostatic gas bearing of the second aspect of the present invention, in the porous hydrostatic gas bearing of the first aspect, the gas supply passage is between the outer peripheral surface and the inner peripheral surface of the porous metal sintered body. In addition, a plurality of annular passages that surround the inner peripheral surface without being exposed to the outside and are arranged in the axial direction with the partition walls of the porous metal sintered body interposed therebetween.
[0009]
According to the porous hydrostatic gas bearing of the second aspect, the gas supply passage is composed of a plurality of annular passages arranged in the axial direction with the partition wall therebetween, in other words, a plurality of annular passages. As a result of the partition wall being present between them, the support function of the partition wall can be expressed. As a result, the gas supply passage is elongated in the axial direction to widen the region where gas can be supplied to the pores of the porous metal sintered body. In this case, the deformation of the porous metal sintered body, which can often occur in this case, can be almost eliminated by the support function of the partition wall.
[0010]
In the porous hydrostatic gas bearing of the third aspect of the present invention, in the porous hydrostatic gas bearing of the second aspect, a plurality of annular passages communicate with each other in the partition wall portion of the porous metal sintered body. A plurality of columnar communication passages are provided.
[0011]
According to the porous hydrostatic gas bearing of the third aspect, since the plurality of annular passages are connected to each other by the communication passage, the gas pressures between the annular passages can be made uniform.
[0012]
In the porous hydrostatic gas bearing of the fourth aspect of the present invention, in the porous hydrostatic gas bearing of any one of the first to third aspects, the porous metal sintered body is fitted in a cylindrical housing. It is exposed to the outside at both end faces.
[0013]
According to the porous hydrostatic gas bearing of the fourth aspect, the outer peripheral surface of the porous metal sintered body can be sealed by the housing, and the outer peripheral surface of the pores of the porous metal sintered body can be processed. Gas can be prevented from being unnecessarily ejected from the opening, and both end faces of the porous metal sintered body can be used as thrust bearing surfaces.
[0014]
In the porous hydrostatic gas bearing of the fifth aspect of the present invention, in the porous hydrostatic gas bearing of any one of the first to fourth aspects, the porous metal sintered body includes an inner peripheral surface thereof and its An exhaust passage having one end opened to the outside is provided in the vicinity where the one end surface intersects, and the exhaust passage is defined by a non-porous tube.
[0015]
According to the porous hydrostatic gas bearing of the fifth aspect, since the exhaust passage opening to the outside is provided in the vicinity where the inner peripheral surface and the one end surface intersect, the inner surfaces that collide with each other in the vicinity are provided. The gas ejected from the peripheral surface and the gas ejected from one end surface can be exhausted from the exhaust passage, and the action of the porous static pressure gas bearing due to the colliding gas can be eliminated, and there is no exhaust passage. Since it is defined by the fine tube, the gas from the fine pores of the porous metal sintered body does not flow directly into the exhaust passage, and the gas can be used without waste.
[0016]
The non-porous tube is preferably a metal or resin pipe like the porous static pressure gas bearing of the sixth aspect of the present invention, but other tubes that do not leak gas. There may be.
[0017]
The method for producing a porous hydrostatic gas bearing according to the first aspect of the present invention includes cylindrical inner and outer green compacts containing metal powder, and includes the outer peripheral surface of the inner green compact and the outer green compact. A preparatory step of preparing the inner and outer green compacts in which an annular recess is formed in any one of the peripheral surfaces, and an outer compact by inserting the inner green compact into the prepared outer green compact A combined body manufacturing process for manufacturing a combined body of the green compact and the inner green compact, and sintering the manufactured combined body, the inner peripheral surface of the outer green compact and the outer peripheral surface of the inner green compact. A porous metal sintered body producing step for producing a porous metal sintered body as an integrated body in which an annular gas supply passage made of a recess is provided inside, and the porous metal sintered body To form a gas introduction passage for introducing gas into the gas supply passage after the production process in the porous metal sintered body A hole communicating with the gas supply passage; and a boring step of boring the porous metal sintered body.
[0018]
According to the manufacturing method of the first aspect, from a combination of an inner green compact and an outer green compact in which one of the annular recesses is formed, as an integrated body provided with a gas supply passage inside In order to produce a porous metal sintered body, a gas supply passage can be easily formed, and a gas supply passage having a wide gas supply area to the pores of the porous metal sintered body can be produced. When configuring a porous static pressure gas bearing comprising such a porous metal sintered body and a housing fitted with the porous metal sintered body, it is necessary to previously form a gas supply passage in the housing in advance. Therefore, the cost can be sufficiently reduced.
[0019]
In the manufacturing method of the second aspect of the present invention, in the manufacturing method of the first aspect, the inner and outer green compacts contain inorganic powder in addition to the metal powder, and the third aspect of the present invention. In the manufacturing method of the second aspect, in the manufacturing method of the second aspect, the metal powder contains at least tin, phosphorus, and copper, and the inorganic powder includes graphite, boron nitride, graphite fluoride, calcium fluoride, aluminum oxide, and oxidation. In the manufacturing method of the fourth aspect of the present invention, at least one of silicon and silicon carbide is contained. In the manufacturing method of the third aspect, the metal powder further contains nickel or manganese.
[0020]
According to the production method of the second aspect, since the inner and outer green compacts contain inorganic powder in addition to the metal powder, the grinding process is performed to form the bearing surface after sintering. When applied to one side of the bonded body, the metal portion of the porous metal sintered body formed by sintering metal powder is plastically flowed to close the pore openings of the porous metal sintered body. This is an ideal diaphragm where the plastic flow of the metal part is interrupted by the brittle inorganic part, and the clogging of the pore opening is preferably prevented, and the clogging of the pore is suppressed even after the bearing surface is formed. A porous hydrostatic gas bearing having the structured pores can be obtained.
[0021]
In addition, in the manufacturing method of the third aspect, when inorganic powder contains graphite, boron nitride, graphite fluoride, calcium fluoride, etc., these function as solid lubricants. Even if the rotating shafts or sliders to be supported come into contact with each other when they are stationary or started, they are unlikely to be damaged, resulting in a fail-safe porous hydrostatic gas bearing.
[0022]
The metal powder for forming the porous metal sintered body preferably has a particle size of 30 μm to 150 μm, preferably 45 μm to 75 μm. Similarly, the inorganic powder has a particle size of 30 μm to 30 μm. It is preferable to use 300 μm, preferably 45 μm to 150 μm. The sintered density and porosity of the porous metal sintered body using such metal powder and inorganic powder are determined by the sintering time and the sintering temperature. Although it is different, for example, when sintered at a temperature of 800 to 1150 ° C. for 20 to 60 minutes in a reducing atmosphere or vacuum under a pressure of about ² to 7 ton / m ² , the sintered density is approximately 5.15 g / cm ^{2 to} 6.19 g / cm ² and the porosity is 21.1% to 34.1% (in terms of oil content).
[0023]
The manufacturing method according to the fifth aspect of the present invention further includes a fitting step of fitting the porous metal sintered body into the cylindrical housing in the manufacturing method according to any one of the first to fourth aspects. The manufacturing method according to the sixth aspect of the present invention further comprises a grinding step of grinding the surface of the porous metal sintered body to be the bearing surface in the manufacturing method according to any one of the first to fifth aspects. is doing.
[0024]
The porous hydrostatic gas bearing manufactured in the present invention may be used as a rotating shaft or a slider by exposing the porous metal sintered body as it is, like the manufacturing method of the fifth aspect, A porous metal sintered body may be fitted in a housing and used for a rotating shaft or a slider with a housing. When the outer peripheral surface of the porous metal sintered body is covered with such a housing, the porous metal sintered body is porous. The gas discharge from the outer peripheral surface of the sintered metal can be eliminated, and the gas consumption can be suppressed. In the porous hydrostatic gas bearing according to the present invention, as in the manufacturing method of the sixth aspect, a thrust and / or radial bearing surface is usually formed by grinding, and the machining allowance in this grinding is approximately 0.2 mm or less. It is good to be performed in the range.
[0025]
According to a seventh aspect of the present invention, in the preparation step, a porous metal sintered body is prepared by preparing inner and outer green compacts having a plurality of annular recesses arranged in the axial direction. In the process, any one of the above-mentioned methods of forming a gas supply passage having a plurality of annular passages composed of a plurality of annular recesses by integrating the inner peripheral surface of the outer green compact and the outer peripheral surface of the inner green compact. Further, after forming the porous metal sintered body, the hole communicating with the annular passage is made porous in order to form a plurality of cylindrical communication passages that communicate the plurality of annular passages with each other. A drilling step for drilling the sintered metal body is further provided.
[0026]
According to the method of the seventh aspect, the inner and outer green compacts are formed in the porous metal sintered body after the porous metal sintered body preparation step so as to make holes in the porous metal sintered body communicating with the gas supply passage. Compared with the case where the communication path is formed in advance, it is possible to form an accurate communication path with good workability.
[0027]
In addition, as a porous static pressure gas bearing of this invention, any of a thrust bearing, a radial bearing, or a thrust bearing and a radial bearing can be used.
[0028]
Hereinafter, the present invention and embodiments of the present invention will be described based on preferred examples with reference to the drawings. The present invention is not limited to these examples.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2, the porous static pressure gas bearing 1 serving as a thrust bearing and a radial bearing of this example includes a cylindrical housing 8 as well as a cylindrical porous metal sintered body 2. Inside the porous metal sintered body 2, there is provided a gas supply passage 3 for supplying gas to the pores of the porous metal sintered body 2, and the porous metal sintered body 2 has one end 4 is opened at the cylindrical outer peripheral surface 5 of the porous metal sintered body 2, and the other end 6 is opened into the gas supply passage 3 to introduce gas into the gas supply passage 3, in this example, high-pressure air. A passage 7 is provided, and the porous metal sintered body 2 is fitted in a cylindrical housing 8 and is exposed to the outside at both annular end faces 9 and 10 thereof.
[0030]
The cylindrical inner peripheral surface 11 and both end surfaces 9 and 10 of the porous metal sintered body 2 are ground so that the inner peripheral surface 11 serves as a radial bearing surface, and both end surfaces 9 and 10 include thrust bearings. It is formed as a surface. Only one end face of both end faces 9 and 10 may be a thrust bearing surface. In this case, silicon resin or the like is applied to the other end face, and the porous metal sintered body 2 at the end face is applied. Sealing treatment for the pores may be performed.
[0031]
The gas supply passage 3 surrounds the inner peripheral surface 11 without being exposed to the outside between the outer peripheral surface 5 and the inner peripheral surface 11 of the porous metal sintered body 2 and the porous metal sintered body 2. A plurality of, in this example, two annular passages 13 arranged in the axial direction with the partition wall 12 interposed therebetween are provided.
[0032]
In addition to the gas introduction passage 7, a plurality of columnar communication passages 14 (see FIG. 7) that connect the two annular passages 13 to each other are provided in the partition wall portion 12 of the porous metal sintered body. .
[0033]
The rigid housing 8 made of metal has a connection passage 15 that is in communication with the gas introduction passage 7 and is threaded, and an air supply plug is attached to the connection passage 15. Since the cylindrical inner peripheral surface 16 of the housing 8 is in close contact with the outer peripheral surface 5 of the porous metal sintered body 2, pore openings of the porous metal sintered body 2 on the outer peripheral surface 5 are formed. It is sealed. In order to make the sealing process on the outer peripheral surface 5 more complete, an adhesive made of silicon resin or the like is provided between the inner peripheral surface 16 of the housing 8 and the outer peripheral surface 5 of the porous metal sintered body 2. An agent may be interposed.
[0034]
In the porous static pressure gas bearing 1 described above, the high-pressure air supplied to the connection passage 15 is supplied to the annular passage 13 via the gas introduction passage 7, and the high-pressure air supplied to the annular passage 13 is porous metal. It is ejected from the inner peripheral surface 11 and both end surfaces 9 and 10 through the pores of the sintered body 2 to form a high-pressure air film between the rotating shaft 18 (see FIG. 8) and thus porous. The static pressure gas bearing 1 supports the rotary shaft 18 so as to be rotatable in the radial direction and the thrust direction.
[0035]
According to the porous hydrostatic gas bearing 1, since the gas supply passage 3 is provided inside the porous metal sintered body 2, all of the surroundings of the gas supply passage 3 are made of the porous metal sintered body 2. It can be used as a gas supply area to the pores, and thus the area where the air can be supplied to the pores of the porous metal sintered body 2 can be widened, and the ejection of air functioning as a thrust bearing can be sufficiently performed as desired. In addition, it is not necessary to form a gas supply passage in the housing 8 in advance, and therefore the cost can be sufficiently reduced.
[0036]
Further, according to the porous hydrostatic gas bearing 1, the gas supply passage 3 includes the two annular passages 13 arranged in the axial direction with the partition wall 12 interposed therebetween. Since the partition wall portion 12 exists between them, the support function of the partition wall portion 12 can be expressed. As a result, the gas supply passage 3 is simply pivoted to increase the area where air can be supplied to the pores of the porous metal sintered body 2. The bending of the porous metal sintered body 2 that can often occur when elongated in the direction can be almost eliminated by the support function of the partition wall 12, and the annular passages 13 communicate with each other through the communication passages 14. Therefore, the gas pressure between the annular passages 13 can be made uniform.
[0037]
In addition, according to the porous static pressure gas bearing 1, the outer peripheral surface 5 of the porous metal sintered body 2 can be sealed by the housing 8, and the outer periphery of the pores of the porous metal sintered body 2 can be processed. Gas can be prevented from being unnecessarily ejected from the opening in the surface 5, and both end surfaces 9 and 10 of the porous metal sintered body 2 can be used as thrust bearing surfaces.
[0038]
The porous static pressure gas bearing 1 as described above can be manufactured as follows. That is, first, cylindrical inner and outer green compacts 41 and 42 made of, for example, tin, phosphorus, nickel, copper, and graphite as shown in FIGS. Either the outer peripheral surface or the inner peripheral surface of the outer green compact 42, in this example, the inner and outer green compact 41 in which two annular recesses 44 are formed in the outer peripheral surface 43 of the inner green compact 41. And 42 are prepared.
[0039]
Each of the inner and outer green compacts 41 and 42 is, for example, a mixed powder composed of 4 to 10% tin, 10 to 40% nickel, 0.5 to 4% phosphorus, 3 to 10% graphite, and the balance copper. Is produced by applying a pressure of ^{2 to} 7 ton / cm ² .
[0040]
Next, the inner green compact 41 is inserted into the outer green compact 42 to produce a combined body 45 of the outer green compact 42 and the inner green compact 41 as shown in FIG. The body 45 is sintered in a reducing atmosphere or vacuum at a temperature of 800 to 1150 ° C. for 20 to 60 minutes, and the inner peripheral surface 46 of the outer green compact 42 and the outer peripheral surface 43 of the inner green compact 41 are integrated. In addition, a porous metal sintered body 2 as shown in FIG. 6 is manufactured as an integrated body in which an annular gas supply passage 3 having a plurality of annular passages 13 formed of recesses 44 is provided. .
[0041]
After the porous metal sintered body 2 is produced, the cylindrical inner peripheral surface 11 and the annular end surfaces 9 and 10 are turned and then ground to form the inner peripheral surface 11 and the end surfaces 9 and 10 as bearing surfaces. To do. The machining allowance in grinding is preferably performed within a range of approximately 0.2 mm or less.
[0042]
After the manufacturing process of the porous metal sintered body 2 and after the grinding process of the inner peripheral surface 11 and the end faces 9 and 10, the gas introduction passage 7 for introducing gas into the gas supply passage 3 is provided in the porous metal sintered body 2. In order to form a plurality of cylindrical communication passages 14, holes that communicate with the annular passages 13 of the gas supply passage 3 are drilled in the porous metal sintered body 2 with a drill or the like, and the annular passages 13 communicate with each other. Are formed in the porous metal sintered body 2 with a drill or the like.
[0043]
After these drilling steps, as shown in FIG. 7, the porous metal sintered body 2 is communicated with the gas introduction passage 7 and the connection passage 15 in the cylindrical housing 8 in which the connection passage 15 is formed in advance. Thus, the porous static pressure gas bearing 1 as shown in FIG.1 and FIG.2 can be obtained by fitting.
[0044]
In addition, drilling of holes in the porous metal sintered body 2 for forming the inner peripheral surface 11 and the end surfaces 9 and 10 for forming the bearing surface, turning, grinding, and forming the gas introduction passage 7 is performed using the porous metal. It may be performed after the sintered body 2 is fitted in the housing 8.
[0045]
According to the above manufacturing method, the porous hydrostatic gas bearing 1 having the above-described features can be obtained, and the inner green compact 41 and the outer green compact 42 in which the recess 44 is formed are provided. In order to produce the porous metal sintered body 2 as an integrated body provided with the gas supply passage 3 from the combination body 45, the gas supply passage 3 can be easily formed, and the porous metal sintered body 2 can be formed. The gas supply passage 3 having a large area for supplying gas to the pores can be produced, and it is not necessary to form the gas supply passage 3 in the housing 8 in advance, so that the cost can be sufficiently reduced.
[0046]
Further, according to the above manufacturing method, since the inner and outer green compacts 41 and 42 contain inorganic powder in addition to the metal powder, the grinding process is porous to form a bearing surface after sintering. When applied to the metal sintered body 2, the metal portion of the porous metal sintered body 2 formed by sintering the metal powder is plastically flowed to close the pore openings of the porous metal sintered body 2. Even so, the plastic flow of the metal part is interrupted by the brittle inorganic part, and the clogging of the pore is prevented after the bearing surface is formed. It is possible to obtain a porous hydrostatic gas bearing 1 having pores having a narrowed structure.
[0047]
Further, when a solid lubricant such as graphite, boron nitride, fluorinated graphite, or calcium fluoride is used as the inorganic powder, the rotary shaft 18 supported by the porous hydrostatic gas bearing 1 is mutually stationary or started. Even if they come into contact with each other, the porous static pressure gas bearing 1 is not easily damaged and is fail-safe.
[0048]
Further, according to the above-described method, the inner and outer green compacts are formed in order to pierce the porous metal sintered body 2 with holes for communication passages communicating with the annular passage 13 after the manufacturing process of the porous metal sintered body 2. Compared to the case where the communication passages are formed in advance in 41 and 42, the work passage 14 can be formed with good workability and accuracy.
[0049]
By the way, in the porous static pressure gas bearing 1, for example, when the end surface 10 is used as a thrust bearing surface with respect to the rotating shaft 18, the air 51 ejected from the opening of the pores of the end surface 10 toward the inner peripheral surface 11, and the inner peripheral surface 11 may be caused to collide with and interfere with the air 52 ejected from the opening of the 11 pores and directed toward the end face 10 to reduce the action of the porous hydrostatic gas bearing 1, but as shown in FIG. The porous metal sintered body 2 is a non-porous tube fitted to the porous metal sintered body 2 with one end 53 opening to the outside in the vicinity where the inner peripheral surface 11 and the end face 10 intersect. When a plurality of exhaust passages 55 defined by metal or resin pipes 54 are provided and the above-mentioned interfering airs 51 and 52 are discharged to the outside through the exhaust passages 55, the airs that collide with each other. Low action of the porous hydrostatic gas bearing 1 due to 51 and 52 In addition, since the exhaust passage 55 is defined by the non-porous pipe 54, the air from the pores of the porous metal sintered body 2 directly flows into the exhaust passage 55. Therefore, high-pressure air can be used without waste. In this case, the housing 8 may be provided with a through hole 56 communicating with the exhaust passage 55 on the one hand and communicating with the outside on the other side corresponding to the exhaust passage 55.
[0050]
The above is an example of the cylindrical porous hydrostatic gas bearing 1, but the same applies to the plate-like porous hydrostatic gas bearing.
[0051]
【The invention's effect】
According to the present invention, it is possible to reduce the cost, and it is possible to widen a region where gas can be supplied to the pores of the porous metal sintered body, and it is possible to achieve a desired gas ejection functioning as a thrust bearing. A gas bearing and a manufacturing method thereof 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 cross-sectional view of the example shown in FIG.
FIG. 3 is an explanatory diagram of the manufacturing method of the example shown in FIG. 1;
4 is an explanatory diagram of the manufacturing method of the example shown in FIG. 1. FIG.
FIG. 5 is an explanatory diagram of the manufacturing method of the example shown in FIG. 1;
6 is an explanatory diagram of the manufacturing method of the example shown in FIG. 1. FIG.
7 is an explanatory diagram of the manufacturing method of the example shown in FIG. 1. FIG.
FIG. 8 is a cross-sectional view of another preferred example of an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Porous static pressure gas bearing 2 Porous metal sintered compact 3 Gas supply path 7 Gas introduction path

Claims (7)

  Cylindrical inner and outer green compacts containing metal powder, in which an annular recess is formed in one of the outer peripheral surface of the inner green compact and the inner peripheral surface of the outer green compact Preparatory process for preparing inner and outer green compacts, and a combination body manufacturing process for producing a combination of outer green compact and inner green compact by inserting the inner green compact into the prepared outer green compact And sintering the produced combined body to integrate the inner peripheral surface of the outer green compact and the outer peripheral surface of the inner green compact, and an annular gas supply passage made of a recess is provided inside. Porous metal sintered body preparation step for producing a porous metal sintered body as an integrated body, and a gas introduction passage for introducing gas into the gas supply passage after the porous metal sintered body preparation step In order to form the sintered body, a hole communicating with the gas supply passage is made in the porous metal sintered body. Comprising the steps, a porous hydrostatic gas manufacturing method of a bearing.   The method for producing a porous hydrostatic gas bearing according to claim 1, wherein the inner and outer green compacts include inorganic powder in addition to the metal powder.   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 manufacturing method of the porous static pressure gas bearing of Claim 2.   The method for producing a porous hydrostatic gas bearing according to claim 3, wherein the metal powder further contains nickel or manganese.   The manufacturing method of the porous hydrostatic gas bearing as described in any one of Claim 1 to 4 further equipped with the fitting process which fits a porous metal sintered compact in a cylindrical housing.   The manufacturing method of the porous static pressure gas bearing as described in any one of Claim 1 to 5 further equipped with the grinding process of grinding the surface of the porous metal sintered compact used as a bearing surface.   In the preparation step, inner and outer green compacts having a plurality of annular recesses arranged in the axial direction are prepared, and in the porous metal sintered body manufacturing step, the inner peripheral surface of the outer green compact A gas supply passage having a plurality of annular passages comprising a plurality of annular recesses is formed by integrating the outer peripheral surface and the outer peripheral surface of the inner green compact. A method for producing a high-pressure static pressure gas bearing, and further, after the porous metal sintered body manufacturing step, communicates with the annular passage so as to form a plurality of cylindrical communication passages that communicate the plurality of annular passages with each other. A method for producing a porous hydrostatic gas bearing, further comprising a drilling step of drilling a hole to be formed in the porous metal sintered body.

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