TW201408897A - Aerostatic radial bearing - Google Patents

Abstract

Provided is an aerostatic radial bearing with which a compressed gas can be uniformly discharged from the entire bearing surface, and with which a high contraction effect can be obtained. This aerostatic radial bearing (1A) is equipped with: a cylindrical first metal powder sintered layer part (2A), the inner circumferential surface (21) of which is a bearing surface; a second metal powder sintered layer (3) formed on the outer circumferential surface (22) of the first metal powder sintered layer part (2A) and having a higher porosity than that of the first metal powder sintered layer part (2A); and a back metal (4) formed on the outer circumferential surface (32) of the second metal powder sintered layer (3). A bead-type bronze alloy powder for which the average grain diameter is substantially the same is used as the material for forming the first and second metal powder sintered layer parts (2A, 3). The second metal powder sintered layer part (3) is arranged within a metal sleeve, with the first metal powder sintered layer part (2A) as a core, and the gap between this core and the sleeve is filed with the bead-type bronze alloy powder, and sintering is performed at a lower temperature and for a shorter time than for the first metal powder sintered layer (2A), thus making the porosity higher than that of the metal powder sintered layer (2A).

Description

Static pressure gas radial bearing

The present invention relates to a static pressure gas radial bearing that supports a load in a radial direction of a rotating body as a supporting object in a non-contact manner, and more particularly relates to a method capable of uniformly discharging a compressed gas from a bearing surface and capable of obtaining more Static pressure gas radial bearing with high adjustment effect.

Patent Document 1 discloses a static pressure gas bearing that can adjust the size and distribution state of the pores formed in the bearing surface with high precision, thereby providing an effect of adjusting the discharge of gas from the bearing surface.

The hydrostatic gas bearing has a base material as a porous material composed of a bronze powder sintered body having an average particle diameter of 60 μm, and is joined as a porous material composed of a bronze powder sintered body having an average particle diameter of 5 μm. The two-layer structure of the surface adjustment layer. As a production method, first, a base material is produced by subjecting a bronze powder sintered body having an average particle diameter of 60 μm to a first sintering treatment. Then, the surface of the base material which is the joint surface with the surface adjustment layer is finished by mechanical processing, and thereafter, the bronze powder having an average particle diameter of 5 μm which is a surface adjustment layer filled in the container is formed. At the end, the base material is placed below the surface of the base material which is the joint surface of the surface adjustment layer, and the second sintering treatment is performed. Thereby, a static pressure gas bearing composed of a sintered body having a two-layer structure of a base material and a surface conditioning layer can be produced.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-27865

However, the static pressure gas bearing described in Patent Document 1 is a plate type bearing used for a thrust bearing, which is not considered to be applied to a shaft used for a radial bearing. Bush type bearing. Further, since the base material and the surface regulating layer are made of bronze powder having different average particle diameters, the management and preparation costs of the materials are improved. Further, since the bronze powder constituting the base material is subjected to sintering treatment in advance to prepare a base material, the bronze powder constituting the surface conditioning layer is sintered to form a surface conditioning layer on the base material, so that secondary sintering is required. Processing, manufacturing costs increase. Therefore, the cost is further increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a static pressure gas radial bearing capable of uniformly discharging a compressed gas from a bearing surface and capable of obtaining a higher adjustment effect. Further, another object of the present invention is to provide a static pressure gas radial bearing which can be manufactured at low cost.

In order to solve the above-described problems, in a first aspect of the present invention, a cylindrical first metal powder sintered layer portion having an inner circumferential surface as a bearing surface is used as a core, and the core portion is disposed in a cylindrical mold. And filling a metal powder in the gap between the core and the mold and sintering, thereby forming a static pressure gas radial bearing formed on the outer peripheral surface of the sintered portion of the first metal powder, and having a porosity ratio of the first The metal powder sintered layer portion is also a larger second metal powder sintered layer portion.

For example, the first aspect of the present invention is a radial pressure static radial gas bearing of a rotating body which is supported by a bearing surface non-contact support, and includes: a cylindrical first metal powder sintered layer portion The inner circumferential surface is the bearing surface; and the second metal powder sintered layer portion is formed on the outer circumferential surface of the first metal powder sintered layer portion and has a more than the first metal powder sintered layer portion In the case of a large porosity, the first metal powder sintered layer portion is formed by performing primary sintering, and the second metal powder sintered layer portion is formed by using the first metal powder sintered layer portion as a core portion. The portion is disposed in a cylindrical mold, and is formed by filling a metal powder in a gap between the core portion and the mold and performing secondary sintering.

Here, the first and second metal powders may be sintered. In the layer portion, a metal powder having substantially the same average particle diameter is used, and the second metal is formed by sintering at a lower temperature and a shorter secondary sintering condition than the primary sintering condition of the first metal powder sintered layer portion. Powder sintered layer.

Further, in a second aspect of the present invention, a cylindrical powder compact comprising a mixed powder of electrolytic copper powder and tin powder is used as a core portion, and the core portion is placed in a cylindrical mold, and Filling and sintering the spherical bronze alloy powder in the gap between the core and the mold, thereby forming a static pressure gas radial bearing having a cylindrical first metal powder sintered layer portion having an inner peripheral surface as a bearing surface; a second metal powder sintered layer portion formed on the outer peripheral surface of the first metal powder sintered layer portion and having a porosity higher than that of the first metal powder sintered layer portion.

For example, the second aspect of the present invention is a radial-loaded static-pressure gas radial bearing of a rotating body that supports a non-contact bearing surface as a support object, and includes: a cylindrical first metal powder sintered layer portion The inner circumferential surface is the bearing surface; and the second metal powder sintered layer portion is formed on the outer circumferential surface of the first metal powder sintered layer portion and has a more than the first metal powder sintered layer portion In the large porosity, the first and second metal powder sintered layer portions are formed by a cylindrical powder compact comprising a mixed powder of electrolytic copper powder and tin powder, and the core portion is disposed on the core portion. In a cylindrical mold, and by filling a spherical bronze alloy powder in the gap between the core and the mold and sintering it to make.

Further, in the first and second aspects, a metal sleeve may be used as the cylindrical mold, whereby the sleeve functions as a backing metal. Alternatively, a laminate composed of the first metal powder sintered layer portion and the second metal powder sintered layer portion may be formed by using a molding die as a cylindrical mold, and then the laminate may be pressed into the metal. A sleeve is formed whereby the sleeve functions as a backing metal.

The present invention provides a static pressure gas radial bearing which is formed by a first metal powder sintered layer portion or a cylindrical powder compact comprising a mixed powder of electrolytic copper powder and tin powder. The core portion is disposed in a cylindrical mold, and is filled with metal powder by a gap between the core portion and the mold, and sintered, whereby the porosity is compared with the cylindrical first metal powder having the inner peripheral surface as a bearing surface. Since the second metal powder sintered layer portion having a larger sintered layer portion is formed in the first metal powder sintered layer portion, the compressed gas can be uniformly discharged from the bearing surface uniformly, and a higher adjustment effect can be obtained.

Further, in the present invention, metal powder having substantially the same average particle diameter is used in the first and second metal powder sintered layer portions, and is further cooled at a lower temperature than the primary sintering condition of the sintered portion of the first metal powder. When the second sintering condition of the second metal powder is formed in the short-time secondary sintering condition, since the same material can be used in the first and second metal powder sintered layer portions, the management of the material and the preparation cost can be reduced. Low Cost to manufacture static pressure gas radial bearings.

Further, in the present invention, the cylindrical powder compact composed of the mixed powder containing the electrolytic copper powder and the tin powder is used as a core portion, and the core portion is placed in a cylindrical mold, and the core is placed in the core. When the gap between the portion and the mold is filled with the spherical bronze alloy powder and sintered to form the first and second metal powder sintered layer portions, the first and second metal powder sintered layers can be simultaneously formed by one sintering. Since the columnar core portion for forming the through hole into which the support object is inserted is not required, the manufacturing cost can be reduced, whereby the static pressure gas radial bearing can be manufactured at low cost.

1A, 1B, 1C‧‧‧Static gas radial bearings

2A, 2B, 2C‧‧‧ first metal powder sintered layer

3‧‧‧Second metal powder sintered layer

4‧‧‧Back pad metal

5‧‧‧Powder

6‧‧‧Spherical bronze alloy powder

7‧‧‧Sleeve

11‧‧‧through holes

21‧‧‧The inner circumferential surface (bearing surface) of the first metal powder sintered layers 2A to 2C

22‧‧‧The outer surface of the first metal powder sintered layer 2A to 2C

23‧‧‧ Both ends of the first metal powder sintered layer 2A to 2C

31‧‧‧ Inner circumference of the second metal powder sintered layer 3

32‧‧‧The outer surface of the second metal powder sintered layer 3

33‧‧‧ Both ends of the second metal powder sintered layer 3

Fig. 1(A) is an external view of the static pressure gas radial bearings 1A to 1C according to the first to third embodiments of the present invention; and Fig. 1(B) is a static pressure gas radial bearing according to the first embodiment of the present invention. 1A is a front view; FIG. 1(C) is a cross-sectional view taken along line AA of the static pressure gas radial bearing 1A shown in FIG. 1(B).

Fig. 2(A) is a front view of a hydrostatic gas radial bearing 1B according to a second embodiment of the present invention; and Fig. 2(B) is a BB of a hydrostatic gas radial bearing 1B shown in Fig. 2(A). Fig. 2(C) is a schematic view showing the arrangement in the mold.

Fig. 3(A) is a front view of a static pressure gas radial bearing 1C according to a third embodiment of the present invention; and Fig. 3(B) is a CC of a static pressure gas radial bearing 1C shown in Fig. 3(A). Cutaway view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1(A) is an external view showing the hydrostatic gas radial bearings 1A to 1C of the first to third embodiments of the present invention.

<First Embodiment>

First, a first embodiment of the present invention will be described.

Fig. 1(B) is a front view of the static pressure gas radial bearing 1A of the present embodiment, and Fig. 1(C) is a cross-sectional view taken along line A-A of the static pressure gas radial bearing 1A shown in Fig. 1(B).

As shown in the figure, the static pressure gas radial bearing 1A of the present embodiment includes a cylindrical first metal powder sintered layer portion 2A having an inner peripheral surface 21 as a bearing surface, and a first metal powder sintered layer portion. a second metal powder sintered layer portion 3 on the outer peripheral surface 22 of 2A; and a backing metal 4 formed on the outer peripheral surface 32 of the sintered portion of the two-metal powder. With such a configuration, the static pressure gas radial bearing 1A supports the load in the radial direction of the rotating body to be supported in a non-contact manner.

The first metal powder sintered layer portion 2A is composed of a porous body obtained by sintering a spherical bronze alloy powder. For example, the through hole 11 into which the rotating body to be supported is inserted is formed inside the first metal powder sintered layer portion 2A, and the cylindrical core portions are arranged in a cylindrical shape so as to coincide with each other. In the forming mold, in the core The gap between the outer peripheral surface of the portion and the inner peripheral surface of the forming mold was filled with a spherical bronze alloy powder having a desired average particle diameter, and was produced by one-time sintering after pressurization. In this case, the conditions of the primary sintering such as the sintering temperature and the sintering time can be adjusted so that the porosity of the first metal powder sintered layer portion 2A is, for example, 10% or less.

The second metal powder sintered layer portion 3 is composed of a porous body obtained by sintering a spherical bronze alloy powder having an average particle diameter substantially the same as that of the first metal powder sintered layer portion 2A. For example, the cylindrical first metal powder sintered layer portion 2A is a core portion, and is disposed in a metal cylindrical sleeve using the core portion as a mold so as to coincide with each other. The gap between the outer peripheral surface of the core and the inner peripheral surface of the sleeve is filled with spherical bronze alloy powder, and the core, the filled spherical bronze alloy powder and the sleeve are secondarily sintered together, whereby the second metal powder is used. The sintered layer portion 3 can be formed on the outer peripheral surface 22 of the first metal powder sintered layer portion 2A in a state of being diffusion-bonded to the first metal powder sintered layer portion 2A, and the backing metal 4 is made by the sleeve. It can be formed on the outer peripheral surface 32 of the second metal powder sintered layer portion 3 in a state of being diffused and joined to the second metal powder sintered layer portion 3. In this case, the conditions of the secondary sintering such as the sintering temperature and the sintering time are such that the porosity of the second metal powder sintered layer portion 3 is larger than the porosity of the first metal powder sintered layer portion 2A (for example, The porosity of the sintered portion 3 of the two-metal powder is 25% or more, and is set to be lower than the conditions of primary sintering for a short period of time.

In such a static pressure gas radial bearing 1A, the supply of the backing pad metal 4 to the second metal powder is performed by an air supply pump (not shown) The compressed gas of the outer peripheral surface 32 of the layer portion 3 is interposed between the pores in the second metal powder sintered layer portion 3 to reach the inner peripheral surface 31 of the second metal powder sintered layer portion 3, and is supplied to the first metal powder sintered layer portion. 2A outside the circumference 22 . Thereafter, the pores in the first metal powder sintered layer portion 2A are interposed to reach the inner peripheral surface 21 of the first metal powder sintered layer portion 2A as the bearing surface, and are uniformly discharged from the entire inner peripheral surface 21. Thereby, a compressed gas layer is formed between the bearing surface 21 and the outer peripheral surface of the rotating body (not shown) inserted into the through hole 11 of the static pressure gas radial bearing 1A, and the rotating body can be supported in a non-contact manner. The load in the radial direction. At this time, the porosity (for example, 10% or less) of the first metal powder sintered layer portion 2A is smaller than the porosity (for example, 25% or more) of the second metal powder sintered layer portion 3, and the second metal powder Since the pores in the sintered layer portion 3 function as an adjustment portion of the flow path of the compressed gas, the compressed gas discharged from the inner peripheral surface 21 of the first metal powder sintered layer portion 2A can be adjusted, and the discharge amount can be adjusted.

The hydrostatic gas radial bearing 1A of the present embodiment is formed of a material for forming the first and second metal powder sintered layer portions 2A and 3, and is commonly used for measurement and calculation methods (for example, screening). The spherical bronze alloy powder having an average particle diameter of approximately equal is determined, and the second metal powder is sintered by sintering at a lower temperature and a shorter secondary sintering condition than the primary sintering condition of the first metal powder sintered layer portion 2A. The layer portion 3 thereby forms the porosity of the second metal powder sintered layer portion 3 larger than the porosity of the first metal powder sintered layer portion 2A. Thus, by using the same material in the first and second metal powder sintered layer portions 2A, 3, the management of the material and the cost of preparation can be reduced, thereby making it possible to manufacture at a low cost. A static pressure gas radial bearing 1A is produced.

Moreover, the backing metal 4 can be formed together with the second metal powder sintered layer portion 3 by using a metal sleeve as a mold, whereby the manufacturing cost can be further reduced.

Further, since the first metal powder sintered layer portion 2A is subjected to secondary sintering treatment (primary sintering and secondary sintering), the first metal powder sintered layer portion 2A and the second metal powder sintered layer are sintered in the secondary sintering. The portion 3 is diffusion-bonded, and the sintering energy of the first metal powder sintered layer portion 2A is further progressed, and the porosity of the first metal powder sintered layer portion 2A becomes smaller. Therefore, the compressed gas discharged from the inner peripheral surface 21 of the first metal powder sintered layer portion 2A can be more effectively adjusted, and the static pressure gas radial bearing 1A having a reduced consumption of compressed air and higher rigidity can be realized.

Further, in the present embodiment, a sealing layer (not shown) may be provided on both end faces 23 and 33 of the first and second metal powder sintered layer portions 2A and 3 to prevent compressed gas from being first and second. Both end faces 23, 33 of the metal powder sintered layer portions 2A, 3 leak.

<Second embodiment>

Next, a second embodiment of the present invention will be described.

Fig. 2(A) is a front view of a hydrostatic gas radial bearing 1B according to a second embodiment of the present invention; and Fig. 2(B) is a BB of a hydrostatic gas radial bearing 1B shown in Fig. 2(A). Cutaway view. In addition, in the second drawing, the same functions as those of the static-pressure gas radial bearing 1A of the first embodiment shown in Fig. 1 are denoted by the same reference numerals.

Similarly to the above-described static pressure gas radial bearing 1A, the static pressure gas radial bearing 1B of the present embodiment supports the load in the radial direction of the rotating body to be supported in a non-contact manner.

As shown in the figure, the static pressure gas radial bearing 1B includes a cylindrical first metal powder sintered layer portion 2B having an inner peripheral surface 21 as a bearing surface, and a peripheral portion formed on the first metal powder sintered layer portion 2B. a second metal powder sintered layer portion 3 on the surface 22; and a backing metal 4 formed on the outer peripheral surface 32 of the two-metal powder sintered layer portion 3.

As shown in Fig. 2(C), the first metal powder sintered layer portion 2B is sintered by a cylindrical green compact 5 composed of a copper-tin mixed powder containing at least electrolytic copper powder and tin powder. Formed. Here, the electrolytic copper powder is different from the spherical bronze alloy powder in that it has a shape of a leaf which is easily solidified, and the tin powder is softer than the spherical bronze alloy powder. Therefore, the cylindrical green compact 5 can be easily obtained by press molding of a copper-tin mixed powder containing electrolytic copper powder and tin powder.

The second metal powder sintered layer portion 3 is composed of a porous body obtained by sintering a spherical bronze alloy powder. As shown in Fig. 2(C), the cylindrical green compact 5 which is the first metal powder sintered layer portion 2B is a core portion, and is disposed so as to match the axis of each other. In the cylindrical sleeve 7 made of metal as a mold, a spherical bronze alloy powder 6 having a desired average particle diameter is filled in a gap between the outer peripheral surface of the green compact 5 and the inner peripheral surface of the sleeve 7. The core, the filled spherical bronze alloy powder 6 and the sleeve 7 are sintered together. Thereby, the powder compact 5 can be sintered by one-time sintering treatment, and the first gold can be formed. It is a powder sintered layer portion 2B, and the filled spherical bronze alloy powder 6 can be sintered, and the second metal powder sintered layer portion 3 can be formed in the first metal in a state of being diffusion-bonded with the first metal powder sintered layer portion 2B. The powder sintered layer portion 2B is on the outer peripheral surface 22 of the outer layer. Further, the backing metal 4 can be formed on the outer peripheral surface 32 of the second metal powder sintered layer portion 3 in a state of being diffusedly bonded to the second metal powder sintered layer portion 3 by the sleeve 7. Here, in the spherical bronze alloy powder used for forming the second metal powder sintered layer portion 3, at least the porosity of the second metal powder sintered layer portion 3 can be formed to be larger than that of the first metal powder sintered layer portion 2B. The porosity is also larger for the average particle size. For example, when the porosity of the first metal powder sintered layer portion 2B is 10% or less, the second metal powder sintered layer can be selected so that the porosity of the second metal powder sintered layer portion 3 becomes 25% or more. The average particle diameter of the spherical bronze alloy powder used in the portion 3.

In the static pressure gas radial bearing 1B configured as described above, the compressed gas supplied to the outer peripheral surface 32 of the second metal powder sintered layer portion 3 by the air supply pump (not shown) and the backing pad metal 4 is interposed. The pores in the sintered portion 3 of the metal powder reach the inner peripheral surface 31 of the second metal powder sintered layer portion 3, and are supplied to the outer peripheral surface 22 of the first metal powder sintered layer portion 2B. Thereafter, the pores in the first metal powder sintered layer portion 2B are interposed to reach the inner peripheral surface 21 of the first metal powder sintered layer portion 2B as the bearing surface, and are uniformly discharged from the entire inner peripheral surface 21. Thereby, a compressed gas layer is formed between the bearing surface 21 and a rotating body (not shown) inserted into the through hole 11 of the static pressure gas radial bearing 1B, and the radial direction of the rotating body can be supported in a non-contact manner. Load. At this time, due to the first metal powder sintered layer portion The porosity of 2B (for example, 10% or less) is smaller than the porosity (for example, 25% or more) of the sintered portion 3 of the second metal powder, and the pores in the sintered portion 3 of the second metal powder function as a compressed gas. Since the function of the regulating portion of the flow path is adjusted, the compressed gas discharged from the inner peripheral surface 21 of the first metal powder sintered layer portion 2B can be adjusted, and the discharge amount can be adjusted.

In the static pressure gas radial bearing 1B of the present embodiment, a cylindrical powder compact 5 composed of a copper-tin mixed powder containing at least electrolytic copper powder and tin powder is used as a core portion, and the powder compact is used. 5 is disposed in the cylindrical sleeve 7, and the spherical bronze alloy powder 6 is filled in the gap between the outer peripheral surface of the green compact 5 and the inner peripheral surface of the sleeve 7 and sintered, whereby the sintering can be performed once. The first and second metal powder sintered layer portions 2B and 3 are simultaneously produced in a state of being joined to each other, and the backing metal 4 can be simultaneously joined to the outer peripheral surface 32 of the second metal powder sintered layer portion 3. In addition, since the green compact 5 obtained by press-forming at least the copper-tin mixed powder containing the electrolytic copper powder and the tin powder can be used as the core portion, it is not necessary to prepare the first metal by one-time sintering in advance as the core portion. Powder sintered layer portion 2B. Therefore, unlike the first embodiment described above, the sintering process can be completed in one operation. Therefore, the manufacturing cost can be further reduced as compared with the first embodiment described above, whereby a lower-cost static-pressure gas radial bearing 1B can be manufactured.

Further, similarly to the above-described first embodiment, in the present embodiment, a sealing layer (not shown) may be provided on both end faces 23 and 33 of the first and second metal powder sintered layer portions 2B and 3, Preventing compressed gas from the both end faces 23 of the first and second metal powder sintered layer portions 2B, 3, 33 leaks.

<Third embodiment>

Next, a third embodiment of the present invention will be described.

Fig. 3(A) is a front view of a static pressure gas radial bearing 1C according to a third embodiment of the present invention; and Fig. 3(B) is a CC of a static pressure gas radial bearing 1C shown in Fig. 3(A). Cutaway view. In addition, in the third figure, the same functions as those of the static-pressure gas radial bearing 1A of the first embodiment shown in Fig. 1 are denoted by the same reference numerals.

Similarly to the above-described static pressure gas radial bearings 1A and 1B, the static pressure gas radial bearing 1C of the present embodiment supports the load in the radial direction of the rotating body to be supported in a non-contact manner.

As shown in the figure, the static pressure gas radial bearing 1C includes a cylindrical first metal powder sintered layer portion 2C having the inner peripheral surface 21 as a bearing surface, and a peripheral portion formed on the first metal powder sintered layer portion 2C. a second metal powder sintered layer portion 3 on the surface 22; and a backing metal 4 formed on the outer peripheral surface 32 of the two-metal powder sintered layer portion 3.

The first metal powder sintered layer portion 2C is composed of a porous body obtained by sintering a spherical bronze alloy powder. For example, the through hole 11 into which the rotating body to be supported is inserted is formed inside the first metal powder sintered layer portion 2C, and the cylindrical core portion is disposed in the cylinder so as to coincide with each other. In the forming mold, a spherical bronze alloy powder having a desired average particle diameter is filled in a gap between the outer peripheral surface of the core portion and the inner peripheral surface of the forming mold, and the primary sintering is performed. Made out. In this case, the conditions of the primary sintering such as the sintering temperature and the sintering time can be adjusted so that the porosity of the first metal powder sintered layer portion 2C is, for example, 10% or less.

The second metal powder sintered layer portion 3 is a porous body obtained by sintering a spherical bronze alloy powder having an average particle diameter larger than that of the spherical bronze alloy powder for the first metal powder sintered layer portion 2C. Body composition. For example, the cylindrical first metal powder sintered layer portion 2C is a core portion, and is disposed in a metal cylindrical sleeve using the core portion as a mold so as to be aligned with each other. a gap between the outer peripheral surface of the core portion and the inner peripheral surface of the sleeve is filled with a spherical bronze alloy powder having an average particle diameter larger than that of the spherical bronze alloy powder for the first metal powder sintered layer portion 2C, and The core, the filled average particle diameter is further sintered together with the spherical bronze alloy powder and the sleeve which are larger than the spherical bronze alloy powder for the first metal powder sintered layer portion 2C, whereby the second metal is sintered The powder sintered layer portion 3 can be formed on the outer peripheral surface 22 of the first metal powder sintered layer portion 2C in a state of being diffusion-bonded to the first metal powder sintered layer portion 2C, and the backing metal 4 is made by the sleeve. It can be formed on the outer peripheral surface 32 of the second metal powder sintered layer portion 3 in a state of being diffused and joined to the second metal powder sintered layer portion 3. Here, in the spherical bronze alloy powder for the second metal powder sintered layer portion 3, at least the porosity of the second metal powder sintered layer portion 3 can be formed to be larger than that of the first metal powder sintered layer portion 2C. The rate is also larger for the average particle size. For example, when the porosity of the first metal powder sintered layer portion 2C is 10% or less, the spherical bronze can be selected so that the porosity of the second metal powder sintered layer portion 3 is 25% or more. The average particle size of the gold powder.

In the static pressure gas radial bearing 1C having the above-described configuration, the compressed gas supplied to the outer peripheral surface 32 of the second metal powder sintered layer portion 3 by the air supply pump (not shown) and the backing pad metal 4 is interposed. The pores in the sintered portion 3 of the metal powder reach the inner peripheral surface 31 of the second metal powder sintered layer portion 3, and are supplied to the outer peripheral surface 22 of the first metal powder sintered layer portion 2C. Thereafter, the pores in the first metal powder sintered layer portion 2C are interposed to reach the inner peripheral surface 21 of the first metal powder sintered layer portion 2C as the bearing surface, and are uniformly discharged from the entire inner peripheral surface 21. Thereby, a compressed gas layer is formed between the bearing surface 21 and the outer peripheral surface of the rotating body (not shown) inserted into the through hole 11 of the static pressure gas radial bearing 1C, and the rotating body can be supported in a non-contact manner. The load in the radial direction. At this time, the porosity (for example, 10% or less) of the first metal powder sintered layer portion 2C is smaller than the porosity (for example, 25% or more) of the second metal powder sintered layer portion 3, and the first metal powder Since the pores in the sintered layer portion 2C function as an adjustment portion of the flow path of the compressed gas, the compressed gas discharged from the inner peripheral surface 21 of the first metal powder sintered layer portion 2C can be adjusted, and the discharge amount can be adjusted.

In the static pressure gas radial bearing 1C of the present embodiment, the backing metal 4 and the second metal powder sintered layer portion 3 can be formed by using a metal sleeve as a mold, whereby the manufacturing cost can be reduced. .

In addition, the material of the second metal powder sintered layer portion 3 is formed by using a common particle diameter ratio determined by a common measurement and calculation method (for example, a screening method) as the material of the first metal powder sintered layer portion 2C. The spheroidal bronze alloy powder is further spheroidal bronze alloy powder, and is sintered at a lower temperature and a shorter secondary sintering condition than the primary sintering condition of the first metal powder sintered layer portion 2C. Since the second metal powder is sintered in the layer portion 3, the porosity of the second metal powder sintered layer portion 3 can be more surely formed than the porosity of the first metal powder sintered layer portion 2C.

Further, since the first metal powder sintered layer portion 2C is subjected to secondary sintering treatment (primary sintering, secondary sintering), in the secondary sintering, the first metal powder sintered layer portion 2C and the second metal powder sintered layer are formed. The portion 3 is diffusion-bonded, and the sintering energy of the first metal powder sintered layer portion 2C is further progressed, and the porosity of the first metal powder sintered layer portion 2C becomes smaller. Therefore, clogging is more surely performed in the entire first metal powder sintered layer portion 2C, and the compressed gas discharged from the inner peripheral surface 21 of the first metal powder sintered layer portion 2C can be more effectively adjusted, and the compressed air can be consumed. A lesser and more rigid static pressure gas radial bearing 1C.

Further, in the present embodiment, as in the first embodiment, a sealing layer (not shown) may be provided on both end faces 23 and 33 of the first and second metal powder sintered layer portions 2C and 3 to prevent the sealing layer (not shown). The compressed gas leaks from both end faces 23, 33 of the first and second metal powder sintered layer portions 2C, 3.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the gist of the invention. For example, in each of the above embodiments, the shape of the backing metal 4 is formed into a columnar shape, but may be a columnar shape. Also, the first metal powder is sintered The shape of the bearing surface of the layer portions 2A to 2C is not limited to a columnar shape, and may be a shape that matches the shape of the support object, such as a prismatic column shape.

Moreover, in each of the above-described embodiments, the backing metal 4 and the second metal powder sintered layer portion 3 are formed by using a metal sleeve as a mold, but the present invention is not limited thereto. . For example, a general cylindrical molding die may be used instead of using a metal sleeve as a mold, and the first metal powder sintered layer portion 2C and the second metal powder sintered layer portion 3 may be formed earlier than the backing pad metal 4. After the laminated body is formed, the first and second metal powder sintered layer portions 2A to 2C and 3 which are integrally joined to each other by diffusion bonding are press-fitted into a metal sleeve, whereby the sleeve is used as a backing pad. The function of metal 4.

1A, 1B, 1C‧‧‧Static gas radial bearings

2A, 2B, 2C‧‧‧ first metal powder sintered layer

3‧‧‧Second metal powder sintered layer

4‧‧‧Back pad metal

11‧‧‧through holes

21‧‧‧The inner circumferential surface (bearing surface) of the first metal powder sintered layers 2A to 2C

22‧‧‧The outer surface of the first metal powder sintered layer 2A to 2C

23‧‧‧ Both ends of the first metal powder sintered layer 2A to 2C

31‧‧‧ Inner circumference of the second metal powder sintered layer 3

32‧‧‧The outer surface of the second metal powder sintered layer 3

33‧‧‧ Both ends of the second metal powder sintered layer 3

Claims (6)

A static pressure gas radial bearing is a radial static pressure gas radial bearing of a rotating body that supports a non-contact bearing surface as a support object, and is characterized in that: a cylindrical first metal powder sintered layer portion is provided The inner circumferential surface is the bearing surface; and the second metal powder sintered layer portion is formed on the outer circumferential surface of the first metal powder sintered layer portion and has a more than the first metal powder sintered layer portion In the case of a large porosity, the first metal powder sintered layer portion is formed by performing primary sintering, and the second metal powder sintered layer portion is formed by using the first metal powder sintered layer portion as a core portion. The portion is disposed in a cylindrical mold, and is formed by filling a metal powder in a gap between the core portion and the mold and performing secondary sintering. The static pressure gas radial bearing according to the first aspect of the invention, wherein the first and second metal powder sintered layer portions are spherical green bronze alloy powder having substantially the same average particle diameter, and the second metal powder The sintered layer portion is formed by sintering at a lower temperature and a shorter secondary sintering condition than the primary sintering condition of the first metal powder sintered layer portion. The static pressure gas radial bearing according to the first aspect of the invention, wherein the first metal powder sintered layer portion is larger than a spherical bronze alloy powder used in the sintered portion of the second metal powder. Average grain Spherical bronze alloy powder with a diameter. A static pressure gas radial bearing is a radial static pressure gas radial bearing of a rotating body that supports a non-contact bearing surface as a support object, and is characterized in that: a cylindrical first metal powder sintered layer portion is provided The inner circumferential surface is the bearing surface; and the second metal powder sintered layer portion is formed on the outer circumferential surface of the first metal powder sintered layer portion and has a more than the first metal powder sintered layer portion In the large porosity, the first and second metal powder sintered layer portions are formed by a cylindrical powder compact comprising a mixed powder of electrolytic copper powder and tin powder, and the core portion is disposed on the core portion. The cylindrical mold is formed by filling a spherical bronze alloy powder in the gap between the core and the mold and sintering. The static pressure gas radial bearing according to any one of claims 1 to 4, further comprising: a backing metal formed on an outer circumferential surface of the second metal powder sintered layer portion, the back The mat metal is a metal sleeve used as the above mold. The static pressure gas radial bearing according to any one of claims 1 to 4, further comprising: a backing metal formed on an outer circumferential surface of the second metal powder sintered layer portion, the mold The mold is a molding die, and the backing metal is a metal sleeve into which the sintered portion of the second metal powder is pressed.