JP2017009033A - Cylindrical composite member for hydrostatic gas bearing, process of manufacture of cylindrical composite member and hydrostatic gas bearing with cylindrical composite member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical composite member not producing any poor connection even at an inner circumferential surface of a small-diameter back metal and capable of eliminating possibility of leakage of compression gas, a process of manufacture of this cylindrical composite member and a hydrostatic gas bearing including this cylindrical composite member.SOLUTION: A cylindrical composite member 1 for a hydrostatic gas bearing comprises: a cylindrical copper pipe 2; a cylindrical porous metallic sintered body 6 integrally diffused and connected to an inner circumferential surface 4 of the copper pipe 2 at a cylindrical outer circumferential surface 3, having a cylindrical inner circumferential surface 5, and containing copper; and annular grooves 8 extending in a radial direction from an outer peripheral surface 7 of the copper pipe 2 to a part of the porous metallic sintered member 6 and formed at the copper pipe 2 and the porous metal sintered body 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cylindrical composite member for a static pressure gas bearing using a porous metal sintered body for reducing the flow rate of pressurized gas supplied to the bearing gap, a method for manufacturing the cylindrical composite member, and the cylinder The present invention relates to a static pressure gas bearing provided with a cylindrical composite member.

  Patent Document 1 discloses a bearing material for a porous hydrostatic gas bearing comprising a back metal made of stainless steel and a porous sintered metal layer integrated on at least one surface of the back metal through a bonding layer. In a hydrostatic gas bearing manufactured using this bearing material, a porous sintered metal layer can be firmly integrated with a stainless steel back metal via a bonding layer. Since the porosity of the sintered metal layer is increased, the pressure loss of the compressed gas flowing through the porous sintered metal layer is reduced, and as a result, the air supplied from the surface (bearing surface) of the porous sintered metal layer By increasing the pressure, the flying height of the counterpart material can be increased.

JP 2004-143580 A

  By the way, the hydrostatic gas bearing proposed in Patent Document 1 is made of nickel on the surface of the back metal in order to join the porous metal sintered layer to the back metal made of stainless steel used from the viewpoint of corrosion resistance (rust prevention). It has a bonding layer consisting of two plating layers, a plating layer and a copper plating layer on the surface of the nickel plating layer. For example, the inner surface of a cylindrical back metal having an inner diameter of less than 20 mm is interposed via the bonding layer. In the case of forming a porous metal sintered layer, the inner peripheral surface of the back metal is difficult to be plated, causing unevenness in the plated layer, often resulting in poor plating, resulting in the inside of the back metal of the porous metal sintered layer. There is a risk of causing poor bonding to the peripheral surface, and there is a risk of leakage of compressed gas from the bonded portion between the back metal and the sintered porous metal layer due to poor bonding.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is not to cause poor bonding even on the inner peripheral surface of a small-diameter back metal, and in addition to leakage of compressed gas. An object of the present invention is to provide a cylindrical composite member for a static pressure gas bearing that can eliminate the fear, a method for manufacturing the cylindrical composite member, and a static pressure gas bearing including the cylindrical composite member.

  A cylindrical composite member for a hydrostatic gas bearing according to the present invention includes a cylindrical copper tube and a cylindrical porous metal sintered body integrally diffused and joined to the inner peripheral surface of the copper tube. It has a unity.

  According to the cylindrical composite member of the present invention having the porous metal sintered body that is a means for reducing the flow rate of the compressed gas supplied to the bearing gap in the hydrostatic gas bearing, Since the porous metal sintered body is diffusion-bonded through the peripheral surface, the result is that the copper tube and the porous metal sintered body are firmly bonded. There is no risk of leakage of compressed gas from the joint between the copper tube and the porous metal sintered body without causing poor bonding, and the static pressure gas using the cylindrical composite member of the present invention and the back metal In the bearing, since a softer copper tube is interposed between the porous metal sintered body and the back metal, the pores of the porous metal sintered body directly from the corrosion of the back metal This eliminates the need to use a backing metal made of corrosion-resistant stainless steel. Various be satisfactorily bonded with the back metal by gender, versatility with respect to the back metal is excellent.

  In the present invention, the sintered porous metal is preferably 4 to 10% by mass of tin, 10 to 40% by mass of nickel, 0.1 to 0.5% by mass of phosphorus in addition to copper. 2 to 10% by mass of graphite.

  According to such a cylindrical composite member, since the graphite is contained in the grain boundary of the porous metal sintered body, even if the surface of the porous metal sintered body serving as the bearing surface is machined, Clogging is suppressed, and an ideal aperture structure can be obtained.

  In a preferred example, the cylindrical composite member according to the present invention extends in the radial direction from the outer peripheral surface of the copper tube to a part of the porous metal sintered body and is formed into the copper tube and the porous metal sintered body. It further comprises a groove, preferably an annular groove.

  In the present invention, the copper tube only needs to be made of softer copper or copper alloy than the porous metal sintered body, and preferably oxygen-free copper, phosphorus deoxidized copper, tough pitch copper, bronze and brass. When the composite is produced in a reducing atmosphere that is selected from any of the above and causes hydrogen embrittlement, it is preferably made of oxygen-free copper or phosphorus-deoxidized copper.

  The manufacturing method of the cylindrical composite member for static pressure gas bearings of the present invention includes (a) a step of preparing a cylindrical copper tube, and (b) 4-10% by mass of atomized tin powder in addition to the electrolytic copper powder. A cylindrical shape compression-molded from a mixed powder containing 10 to 40% by weight of electrolytic nickel powder, 0.7 to 3.5% by weight of copper phosphorus (phosphorus 14.5% by weight) alloy powder and 2 to 10% by weight of graphite powder A step of producing a first composite comprising the green compact and the copper tube by inserting the green compact into the copper tube, and (c) 850 the first composite in a reducing atmosphere or vacuum. Heating is performed at a temperature of ˜1000 ° C. for 30 to 90 minutes, and by this heating, a porous metal sintered body is generated from the green compact in the first composite, and the pressure on the inner peripheral surface of the copper tube in this generation process A step of producing a second composite body including a porous metal sintered body integrated with powder diffusion and a copper tube It is equipped with.

  In a preferred example of the production method of the present invention, at least one groove extending from the outer peripheral surface of the copper tube to a part of the porous metal sintered body in the produced second composite, preferably an annular groove, is provided. The method further includes forming the second composite.

  The manufacturing method of the present invention for a cylindrical composite member for a plurality of static pressure gas bearings includes (a) a step of preparing a cylindrical copper tube, and (b) an atomized tin powder 4 to 4 in addition to the electrolytic copper powder. 10% by weight, electrolytic nickel powder 10-40% by weight, copper phosphorus (phosphorus 14.5% by weight) alloy powder 0.7-3.5% by weight and mixed powder containing graphite powder 2-10% by weight. A plurality of cylindrical green compacts were sequentially inserted into the copper tube, and a plurality of green compacts and copper tubes arranged along the longitudinal direction of the copper tube were provided inside the copper tube. A step of producing the first composite; and (c) the first composite is heated in a reducing atmosphere or vacuum at a temperature of 850 to 1000 ° C. for 30 to 90 minutes, and this heating causes the first composite to A porous metal sintered body is produced from the green compact, and the interdiffusion between the green compacts during this production process. A step of producing a second composite body comprising a porous metal sintered body and a copper tube integrated by diffusion of the green compact to the inner peripheral surface of the pipe; and (d) cutting the second composite body. And a step of producing a plurality of second composites.

  In a preferred example, the manufacturing method of the present invention for a cylindrical composite member for a plurality of hydrostatic gas bearings is preferably a porous metal from the outer peripheral surface of the copper tube in each of the plurality of second composite bodies produced. The method further includes the step of forming at least one groove extending to a part of the sintered body, preferably an annular groove, in each of the plurality of second composite bodies.

  In the production method of the present invention, the mixed powder preferably contains 0.1 to 5.0% by mass of a 1 to 15% by weight aqueous solution of a powder binder, and wettability is imparted by such an aqueous solution. By using a mixed powder that is uniformly mixed, the shape retention of a cylindrical green compact produced by compression molding the mixed powder can be improved.

  The powder binder is preferably selected from hydroxypropylcellulose (HPC), polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC), methylcellulose (MC), gelatin, gum arabic and starch, among others Hydroxypropyl cellulose (HPC) is more preferred.

  As a solvent for the powder binder, an aqueous solution of 5 to 20% by mass of a hydrophilic compound such as ethyl alcohol can be used in addition to water alone. The powder binder is preferably blended in an amount of 1 to 15% by weight with respect to such an aqueous solution, and the aqueous solution of the powder binder is preferably blended in an amount of 0.1 to 5.0% by weight with respect to the mixed powder. .

  The method for producing a cylindrical composite member of the present invention utilizes thermal expansion during sintering of a green compact containing graphite powder, and covers the outer peripheral surface of the green compact with the inner peripheral surface of a copper tube. By constraining the thermal expansion of the green compact during powder sintering, contact pressure is applied to the inner peripheral surface of the copper tube from the green compact due to the thermal expansion of the green compact during sintering. The porous metal sintered body is joined and integrated with the inner peripheral surface of the copper tube by causing diffusion of mutual metal components at the contact interface.

  In the mixed powder, the tin of the atomized tin powder forms a bronze by alloying with the copper of the electrolytic copper powder forming the main component in the production of the porous metal sintered body, and the strength of the ground of the porous metal sintered body, In addition to improving the toughness and mechanical strength, the porosity of the sintered porous metal is increased together with the nickel of the electrolytic nickel powder, and if the blending amount is 4% by mass or less, the above-described effects can be sufficiently exhibited. In addition, if it exceeds 10% by mass, the sinterability of the porous sintered metal body may be adversely affected. Therefore, the mixed powder contains 4-10% by mass of atomized tin powder. 5-8 mass% is mix | blended.

In the mixed powder, the nickel of the electrolytic nickel powder diffuses into the copper of the electrolytic copper powder forming the main component in the production of the porous metal sintered body and contributes to the improvement of the strength of the porous metal sintered body, In addition, it diffuses into the inner peripheral surface of the copper tube to alloy the joint interface between the porous metal sintered body and the inner peripheral surface of the copper tube, and joins the porous metal sintered body to the inner peripheral surface of the copper tube. Strength is increased and a part of the copper phosphorus alloy powder is alloyed with phosphorus to form a liquid phase nickel-phosphorus alloy (Ni ₃ P). The nickel-phosphorus alloy is the inner periphery of the porous metal sintered body and the copper tube. The porous metal sintered body is firmly attached to the inner peripheral surface of the copper pipe, coupled with alloying by diffusion of nickel into the inner peripheral surface of the copper pipe at the bonding interface. When the amount is 10% by mass or less, the effects described above are not exhibited, and the amount exceeds 40% by mass. Even for significant difference to the effects mentioned above does not appear, the mixed powder, electrolytic nickel powder is formulated 10 to 40% by mass.

In the mixed powder, phosphorus in the copper-phosphorus alloy powder is used to form a porous metal sintered body. While improving the strength of the ground of the body, the strong reducing power cleans the inner peripheral surface of the copper tube, promotes alloying by diffusion of nickel into the inner peripheral surface of the copper tube, and cooling after sintering The amount of shrinkage of the porous sintered metal body at the time is suppressed low, and the peeling of the porous sintered metal body from the inner peripheral surface of the copper tube due to the shrinkage of the porous sintered metal body is suppressed. In the production process of the porous sintered metal body, the production amount of the liquid phase nickel-phosphorus alloy (Ni ₃ P) is reduced to increase the porosity of the porous sintered metal body. By reducing the pressure loss of the compressed gas that circulates, the air supply pressure ejected from the porous sintered metal body can be relatively increased to increase the flying height. From such a viewpoint, the copper phosphorus alloy powder is blended in an amount of 0.7 to 3.5% by mass (phosphorus 0.1 to 0.5% by mass).

  In mixed powder, unlike many metal materials, graphite of graphite powder, which is an inorganic substance that does not undergo plastic deformation by machining, is a metal part consisting of tin, nickel, phosphorus and copper of the obtained porous sintered metal body Breaks and reduces plastic deformation in the machining of the base material (grain boundaries), suppresses clogging of the porous sintered metal body in machining, and if the blending amount is 2% by weight or less, such an effect is sufficient If it exceeds 10% by weight, it may impair the sinterability of the porous sintered metal body. Therefore, the mixed powder contains 2 to 10% by weight of graphite powder. .

  In the manufacturing method of the present invention for a cylindrical composite member for a plurality of static pressure gas bearings, the copper tube and the plurality of green compacts are an outer peripheral surface of the plurality of green compacts and an inner peripheral surface of the copper tube. And a plurality of green compacts are diffusion-bonded to each other at each joint to form a seamless porous metal sintered body. As a result, the steel tube and the porous metal sintered A plurality of the same cylindrical composite members can be produced from the second composite having the body.

  A static pressure gas bearing according to the present invention includes the above-described cylindrical composite member and a cylindrical back plate having a cylindrical inner peripheral surface to which an outer peripheral surface of a copper tube of the cylindrical composite member is in close contact. ing.

  According to the hydrostatic gas bearing of the present invention, the porous metal sintered body as a means for reducing the flow rate of the compressed gas supplied to the bearing gap is provided on the inner peripheral surface of the back metal through the cylindrical copper tube. As a result, the copper tube can act as a buffer, and the compressive force applied from the back metal in the radial direction of the cylindrical composite member can be absorbed by the copper tube as the buffer. The deformation of the porous metal sintered body due to the compressive force can be avoided, and the cylindrical composite member is in close contact with the inner peripheral surface of the back metal by utilizing the softness of the copper tube. The possibility of leakage of compressed gas from between the peripheral surface and the outer peripheral surface of the cylindrical composite member can be eliminated.

  In the static pressure gas bearing of the present invention, the backing metal may be a backing metal made of stainless steel, but may be made of other resin or inorganic substance.

  The back metal of the hydrostatic gas bearing of the present invention has, in a preferred example, a compressed gas supply passage communicating with a groove of a cylindrical composite member, preferably an annular groove.

  According to the present invention, a cylindrical composite member for a hydrostatic gas bearing that does not cause poor bonding even on the inner peripheral surface of a small-diameter back metal and eliminates the risk of leakage of compressed gas, and the cylinder. A method for producing a cylindrical composite member and a static pressure gas bearing including the cylindrical composite member can be provided.

FIG. 1 is a longitudinal sectional explanatory view of a preferred example of an embodiment of a cylindrical composite member for a static pressure gas bearing of the present invention. FIG. 2 is an explanatory side view of FIG. FIG. 3 is a longitudinal cross-sectional explanatory view of a preferred example of an embodiment of a static pressure gas bearing including the cylindrical composite member of the present invention. 4 is a cross-sectional explanatory view taken along the line IV-IV in FIG. FIG. 5 is a longitudinal cross-sectional explanatory view of another preferred example of an embodiment of a static pressure gas bearing including a cylindrical composite member of the present invention. 6 is a cross-sectional explanatory view taken along the line VI-VI in FIG. FIG. 7 is an explanatory front view of another preferred example of an embodiment of a static pressure gas bearing including a cylindrical composite member of the present invention.

  Next, the present invention and its embodiments will be described in more detail based on preferred embodiments shown in the drawings. In addition, this invention is not limited to these Examples at all.

  A cylindrical composite member 1 for a hydrostatic gas bearing shown in FIGS. 1 and 2 includes a cylindrical copper tube 2 made of oxygen-free copper (JIS alloy number C1020) or phosphorus deoxidized copper (JIS alloy number C1220), The cylindrical outer peripheral surface 3 is integrally diffusion-bonded to the inner peripheral surface 4 of the copper tube 2 and has a cylindrical inner peripheral surface 5, and is a cylindrical porous metal sintered body containing copper. And an annular groove 8 as a groove formed in the copper tube 2 and the porous metal sintered body 6 extending from the outer peripheral surface 7 of the copper tube 2 in the radial direction to a part of the porous metal sintered body 6. It has.

  The porous metal sintered body 6 includes tin (Sn) 4 to 10% by mass, nickel (Ni) 10 to 40% by mass, phosphorus (P) 0.1 to 0.5% by mass, graphite (Gr) It consists of 2-10 mass% and remainder copper (Cu).

  The cylindrical composite member 1 is manufactured as follows. Atomized tin powder 4-10% by mass, electrolytic nickel powder 10-40% by mass, copper phosphorus (phosphorus 14.5% by mass) alloy powder 0.7-3.5% by mass, graphite powder 2-10% by mass And 1-15 mass% aqueous solution of powder binder selected from hydroxypropyl cellulose, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, gelatin, gum arabic and starch 0.1-5.0 mass% is mix | blended with respect to powder, and it mixes uniformly and produces the mixed powder which provided the wettability.

The mixed powder is loaded into a cylindrical mold having a cylindrical inner peripheral surface and an outer peripheral surface, and the mixed powder is compression-molded at a molding pressure in the range of 3 to 5 ton / cm ² , and the cylindrical inner peripheral surface and A green compact having an outer peripheral surface is produced.

  This cylindrical green compact is inserted into the inside defined by the inner peripheral surface 4 of the cylindrical copper pipe 2 made of oxygen-free copper or phosphorous deoxidized copper, and a composite comprising the copper pipe 2 and the green compact. Then, the composite is heated for 30 to 90 minutes at a temperature of 850 to 1000 ° C. in a reducing furnace or in a sintering furnace adjusted to a vacuum to cauterize the green compact. In this heating and cauterization process, the green compact causes volume expansion (thermal expansion), and the volume expansion of the green compact causes a high contact pressure between the inner peripheral surface 4 and the outer peripheral surface of the green compact. The porous metal sintered body 6 and copper in which the contact pressure causes the component of the green compact to diffuse to the inner peripheral surface 4 and sinter, thereby causing the outer peripheral surface 3 to be closely joined to the inner peripheral surface 4. A composite with tube 2 is prepared.

  A cylindrical composite member is formed by forming an annular groove 8 extending from the outer peripheral surface 7 of the copper tube 2 to a part of the porous metal sintered body 6 in the composite comprising the porous metal sintered body 6 and the copper tube 2. 1 is produced. C chamfering or R chamfering 9 may be formed on the outer peripheral surface 7 of the copper tube 2 at both ends in the axial direction of the cylindrical composite member 1.

  The cylindrical composite member 1 may be manufactured as follows using a cylindrical long copper tube 2 made of oxygen-free copper or phosphorus-deoxidized copper and a plurality of green compacts.

  First, a plurality of green compacts prepared in the same manner as described above are sequentially inserted into the inside defined by the inner peripheral surface 4 of a cylindrical long copper tube 2 made of oxygen-free copper or phosphorus-deoxidized copper. After producing a composite comprising a plurality of green compacts arranged in the longitudinal direction (axial direction) of the copper tube 2 and the long copper tube 2 inside the copper tube 2, A plurality of green compacts are sintered by heating at a temperature of 850 to 1000 ° C. for 30 to 90 minutes in a reducing furnace or in a sintering furnace adjusted to a vacuum. In this heating and sintering process, volume expansion (thermal expansion) occurs in each of the plurality of green compacts, and the inner peripheral surface 4 and the respective outer peripheral surfaces of the plurality of green compacts by the volume expansion of the plurality of green compacts. And a plurality of green compacts cause a high contact pressure, and this contact pressure causes the components of the green compact to diffuse to the inner peripheral surface 4 and also causes diffusion between the green compacts. Thus, a long composite comprising the porous metal sintered body 6 and the copper tube 2 integrated by tightly joining the outer peripheral surfaces 3 to the inner peripheral surface 4 and joining the green compacts together. Make it.

  Then, this long composite is cut to produce a plurality of composites, and an annular groove 8 extending from the outer peripheral surface 7 of the copper tube 2 of each composite to a part of the porous metal sintered body 6 is formed. By doing so, a plurality of cylindrical composite members 1 are produced. C chamfering or R chamfering 9 may be formed on the outer peripheral surface 7 of the copper tube 2 at both axial ends of the plurality of cylindrical composite members 1.

  According to the cylindrical composite member 1 described above, since the porous metal sintered body 6 is diffusion bonded to the copper tube 2 made of oxygen-free copper or phosphorus deoxidized copper via the inner peripheral surface 4, the copper tube 2 As a result of the strong bonding between the copper tube 2 and the porous metal sintered body 6, even the inner peripheral surface 4 of the small-diameter copper tube 2 does not cause poor bonding, and the copper tube 2 and the porous metal sintered body are sintered. The possibility of leakage of compressed gas from the joint with the body 6 can be eliminated.

  3 and 4 includes a cylindrical composite member 1, a cylindrical outer peripheral surface 11, a cylindrical inner peripheral surface 12 in which the outer peripheral surface 7 is in close contact, and an outer peripheral surface 11 and a cylindrical inner peripheral surface. A cylindrical back metal 14 formed of stainless steel having a hole 13 as a passage for supplying compressed gas, which is open in each of 12 and extends radially from the outer peripheral surface 11 to the cylindrical inner peripheral surface 12; The cylindrical composite member 1 is integrally fitted and coupled to the cylindrical inner peripheral surface 12 with the annular groove 8 corresponding to the hole 13 so that the annular groove 8 communicates with the hole 13. The static pressure gas bearing 10 has a cylindrical inner peripheral surface 5 as a bearing surface.

  As the stainless steel forming the back metal 14, austenitic stainless steel, martensitic stainless steel or ferritic stainless steel, preferably martensitic stainless steel or ferritic stainless steel having a low chromium (Cr) content is used. The

  According to the static pressure gas bearing 10, when the cylindrical composite member 1 is press-fitted (fitted) into the back metal 14 defined by the cylindrical inner peripheral surface 12 and fixed to the cylindrical inner peripheral surface 12, the cylindrical composite member 1 is absorbed by the malleability of the copper tube 2, and the copper tube 2 acts as a buffer against the compressive force, so that the porous metal diffused and joined to the inner peripheral surface 4. The sintered body 6 is not affected by the compressive force, and the inner peripheral surface 5 serving as the bearing surface does not cause a problem such as a dimensional change.

  In the static pressure gas bearing 10, the compressed gas supplied to the holes 13 can be supplied from the annular groove 8 corresponding to the holes 13 to the porous metal sintered body 6, and the outer peripheral surface 7 is in close contact with the cylindrical inner peripheral surface 12. Therefore, the compressed gas can be ejected substantially uniformly from the inner peripheral surface 5, that is, the bearing surface.

  In the example of the static pressure gas bearing 10 shown in FIGS. 5 and 6, the cylindrical composite member 1 includes two annular grooves 8 spaced apart in the axial direction instead of one annular groove 8. Reference numeral 14 denotes a dead end hole 17 extending in the axial direction from one annular end face 15 in the axial direction toward the other annular end face 16, and a compression extending in the radial direction from the cylindrical inner peripheral face 12 and opening to the dead end hole 17. Further, a gas supply hole 18 is provided, the hole 13 communicates with one annular groove 8 and the dead end hole 17, and the cylindrical composite member 1 has the outer peripheral surface 7 formed on the cylindrical inner peripheral surface 12. The annular groove 8 is integrally fitted and coupled to the cylindrical inner peripheral surface 12 so as to correspond to the hole 13 and the hole 18, respectively, so that the annular groove 8 communicates with the hole 13 and the hole 18, respectively. Also in the example static pressure gas bearing 10, the cylindrical inner peripheral surface 5 is used as a bearing surface.

  The dead end hole 17 is closed by a stopper 20 at one end 19 in the axial direction, and the stopper 20 is screwed to a female screw 21 formed in the back metal 14 at one end 19 in the axial direction of the dead end hole 17. The other end 22 in the axial direction of the dead end hole 17 opens into one hole 13.

  In the hydrostatic gas bearing 10 shown in FIGS. 5 and 6, a hole is formed from one annular groove 8 corresponding to the hole 13 and the other annular groove 8 corresponding to the hole 18 opened to the dead end hole 17 communicating with the hole 13. The compressed gas supplied to 13 can be supplied to the porous metal sintered body 6, the outer peripheral surface 7 is in close contact with the cylindrical inner peripheral surface 12, and the copper tube 2 and the cylindrical composite member 1 are integrally coupled. Therefore, the compressed gas can be ejected from the inner peripheral surface 5, that is, the bearing surface substantially uniformly.

  A static pressure gas bearing 10 shown in FIG. 7 is opened in the radial direction by two cylindrical composite members 1 and a cylindrical outer peripheral surface 11 of one end 23, and from the outer peripheral surface 11 to a cylindrical inner peripheral surface 12. The cylindrical outer peripheral surface 11 of the one hole 13 and the other end 24 that extend in the radial direction toward the inside and open at the cylindrical inner peripheral surface 12 opens in the radial direction and from the outer peripheral surface 11 to the inside of the cylinder. Each of the cylindrical composite members 1 includes an outer peripheral surface 7 extending in the radial direction toward the peripheral surface 12 and having a back plate 14 having the other hole 13 opened at the cylindrical inner peripheral surface 12. The annular inner groove 12 is in close contact with the inner circumferential surface 12 and is integrally coupled to the inner circumferential surface 12 corresponding to the compressed gas supply holes 13 and 13 formed in the back metal 14, respectively. The hydrostatic gas bearing 10 shown is a cylinder of each porous metal sintered body 6 of two cylindrical composite members 1. The inner peripheral surface 5 has a bearing surface.

  According to the hydrostatic gas bearing 10 described above, the porous metal sintered body 6 as means for reducing the flow rate of the compressed gas supplied to the bearing gap is provided on the inner peripheral surface 4. Since it is fixed to the cylindrical inner peripheral surface 12 of the back metal 14 made of stainless steel through the copper tube 2 made of oxygen-free copper or phosphorus deoxidized copper integrally diffusion-bonded, the conventional porous metal sintered body is made It eliminates the need for two plating layers consisting of a nickel plating layer and a copper plating layer, which are essential for joining to the inner peripheral surface of a stainless steel back metal, and can solve the problems caused by the two plating layers. Moreover, since the copper tube 2 interposed between the back metal 14 and the porous metal sintered body 6 acts as a buffer, the compressive force applied in the radial direction of the cylindrical composite member 1 from the back metal 14 is applied to the copper tube 2. As a result of absorption, the porous metal sintered body 6 is compressed by such a compressive force. Since the cylindrical composite member 1 is in close contact with the cylindrical inner peripheral surface 12 of the back metal 14, there is a risk of leakage of compressed gas from between the cylindrical inner peripheral surface 12 and the outer peripheral surface 7. It can be lost.

DESCRIPTION OF SYMBOLS 1 Cylindrical composite member 2 Copper pipe 5 Inner peripheral surface 6 Porous metal sintered compact 8 Annular groove 10 Hydrostatic gas bearing 13 Hole

Claims (10)

  A cylindrical composite for a hydrostatic gas bearing comprising a cylindrical copper tube and a cylindrical porous metal sintered body integrally diffused and bonded to the inner peripheral surface of the copper tube and containing copper Element.   The porous metal sintered body comprises, in addition to copper, 4 to 10% by mass of tin, 10 to 40% by mass of nickel, 0.1 to 0.5% by mass of phosphorus, and 2 to 10% by mass of The cylindrical composite member for a static pressure gas bearing according to claim 1, comprising graphite.   3. The apparatus according to claim 1, further comprising at least one groove formed in the copper tube and the porous metal sintered body so as to extend from the outer peripheral surface of the copper tube in a radial direction to a part of the porous metal sintered body. Cylindrical composite member for static pressure gas bearings.   (A) a step of preparing a cylindrical copper tube, and (b) in addition to the electrolytic copper powder, 4-10 mass% of atomized tin powder, 10-40 mass% of electrolytic nickel powder, copper phosphorus (phosphorus 14.5 mass) %) A cylindrical green compact formed by compression molding from a mixed powder containing 0.7 to 3.5% by mass of alloy powder and 2 to 10% by mass of graphite powder is inserted into a copper tube, and the green compact and copper A step of producing a first composite having a tube; and (c) heating the first composite in a reducing atmosphere or in a vacuum at a temperature of 850 to 1000 ° C. for 30 to 90 minutes. Porous metal sintered body and copper tube formed by compacting a porous metal sintered body from a green compact in a composite of the present invention and diffusing the green compact into the inner peripheral surface of the copper tube in this production process For producing a cylindrical composite member for a static pressure gas bearing comprising the step of producing a second composite comprising   5. The method according to claim 4, further comprising the step of forming at least one groove extending from the outer peripheral surface of the copper tube to a part of the porous metal sintered body in the produced second composite in the second composite. A method for producing a cylindrical composite member for a static pressure gas bearing.   (A) a step of preparing a cylindrical copper tube, and (b) in addition to the electrolytic copper powder, 4-10 mass% of atomized tin powder, 10-40 mass% of electrolytic nickel powder, copper phosphorus (phosphorus 14.5 mass) %) A plurality of cylindrical green compacts compression-molded from a mixed powder containing 0.7 to 3.5% by mass of alloy powder and 2 to 10% by mass of graphite powder are sequentially inserted into the inside of the copper tube. Producing a first composite comprising a plurality of green compacts and copper tubes arranged along the longitudinal direction of the copper tube inside the copper tube; and (c) reducing the first composite. In a neutral atmosphere or vacuum at a temperature of 850 to 1000 ° C. for 30 to 90 minutes, and by this heating, a porous metal sintered body is produced from the green compact in the first composite and the green compact in this production process Porous metal sintered body integrated by mutual diffusion between bodies and diffusion of green compact to inner peripheral surface of copper tube A plurality of static pressures comprising: a step of producing a second composite body comprising a copper tube; and (d) a step of producing a plurality of second composite bodies by cutting the second composite body. A method for producing a cylindrical composite member for a gas bearing.   Forming at least one groove extending from the outer peripheral surface of the copper tube to a part of the porous metal sintered body in each of the plurality of second composite bodies in each of the plurality of second composite bodies. The manufacturing method of the cylindrical composite member for several static pressure gas bearing of Claim 6 which further comprised these.   The mixed powder contains 0.1 to 5.0% by mass of an aqueous solution of 1 to 15% by mass of a powder binder selected from hydroxypropylcellulose, polyvinyl alcohol, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, gelatin, gum arabic and starch. The manufacturing method of the cylindrical composite member for static pressure gas bearings as described in any one of Claims 4-7 currently mix | blended.   A static pressure gas comprising the cylindrical composite member according to claim 1 and a cylindrical backing metal having a cylindrical inner peripheral surface to which an outer peripheral surface of a copper tube of the cylindrical composite member is in close contact. bearing.   The cylindrical composite member according to claim 3, a cylindrical inner peripheral surface where the outer peripheral surface of the copper pipe of the cylindrical composite member is in close contact, and a compressed gas supply passage communicating with the groove of the cylindrical composite member are provided. A hydrostatic gas bearing comprising a cylindrical backing metal.

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