JP7506581B2 - Gas restriction structure for hydrostatic gas bearing and hydrostatic gas bearing - Google Patents

Description

The present invention relates to a gas throttling structure for a hydrostatic gas bearing and a hydrostatic gas bearing.

In an externally pressurized gas bearing, which supports an object by utilizing the pressure of a pressurized fluid introduced into the bearing from outside the bearing, a portion that creates resistance to the gas flow, known as a throttle, is provided just before the gap (bearing clearance) between the object to be supported and the externally pressurized gas bearing.
If a throttle is provided in a hydrostatic gas bearing, the pressure of the gas (gas film) filling the entire bearing clearance will increase when the bearing clearance becomes smaller, and the pressure of the gas film in the bearing clearance will decrease when the bearing clearance becomes larger. Therefore, the supported object can be held in a floating state above the hydrostatic gas bearing at a position where the load applied to the hydrostatic gas bearing and the pressure of the gas film in the bearing clearance are balanced.

As one of such gas restrictor structures for hydrostatic gas bearings, a porous restrictor that utilizes air-permeable porous material has been conventionally known.
A porous restrictor is a type of restrictor that utilizes fine holes formed in a porous body as a restrictor and that utilizes the surface of the porous body as a surface for supplying air into the bearing clearance. Known examples of porous bodies include those made from sintered metal powder (see, for example, Patent Document 1).

JP-A-10-299779 (particularly, [0025])

In a porous restrictor, since the air permeability of the porous body is directly related to the load capacity (load resistance of the hydrostatic gas bearing) of the hydrostatic gas bearing, control of the air permeability of the porous body is extremely important.
However, the above-mentioned porous bodies using sintered metals have large individual differences in air permeability, and there is room for further improvement in controlling air permeability.

The present invention solves the problems of the prior art as described above. In other words, the object of the present invention is to provide a gas throttling structure for a hydrostatic gas bearing and a hydrostatic gas bearing that can easily adjust the air permeability while realizing surface air supply into the bearing gap.

The invention according to claim 1 is a gas throttle structure for a hydrostatic gas bearing formed in a tubular gas flow passage and facing a support object, in which a number of gas throttle layers laminated from the upstream side to the downstream side of the tubular gas flow passage are each composed of a pipe wall portion forming the tubular gas flow passage and a number of rib portions bridged and integrally formed with the inner wall surface of the pipe wall portion, the rib portions of the gas throttle layer divide and block the flow passage cross section of the pipe wall portion of the gas throttle layer in parallel at a predetermined rib arrangement interval, the gas throttle layer is integrated with the pipe wall portion and the rib portion adjacent along the tubular gas flow passage, and the rib portions of the adjacent gas throttle layers are arranged in different bridge directions between the adjacent gas throttle layers, thereby solving the above-mentioned problem.

The invention according to claim 2 further solves the above-mentioned problem by, in addition to the configuration of the gas throttle structure described in claim 1, the gas throttle layer provided on the outermost surface facing the supported object has connecting portions that connect the rib portions at a predetermined interval, the total flow path cross-sectional area of the gas throttle layer provided on the outermost surface is smaller than the total flow path cross-sectional area of the gas throttle layers other than the gas throttle layer provided on the outermost surface, the pipe wall portion of the gas throttle layer provided on the outermost surface is integrated with the pipe wall portion of the gas throttle layer adjacent to and facing the gas throttle layer provided on the outermost surface, and the connecting portion of the gas throttle layer provided on the outermost surface is integrated with the rib portion of the gas throttle layer adjacent to and facing the gas throttle layer provided on the outermost surface.

The invention according to claim 3 is a hydrostatic gas bearing comprising a base plate in which an air supply hole that communicates with an air supply source and forms the inlet end of a tubular gas flow path and an outlet hole that forms the outlet end of the tubular gas flow path are formed, and a gas throttle member that is inserted into and tightly attached to the outlet hole formed on the surface of the base plate, and the gas throttle member has the gas throttle structure according to claim 1 or claim 2, thereby solving the above-mentioned problem.

The invention according to claim 4 further solves the above-mentioned problem by, in addition to the configuration of the hydrostatic gas bearing described in claim 3, the outlet surface of the gas throttling member being flush with the surface of the base plate or recessed below the surface of the base plate.

The invention of claim 1 is a gas throttling structure for an hydrostatic gas bearing formed in a tubular gas flow path and facing the supported object, so that air is supplied to the bearing clearance between the supported object and the gas throttling structure, thereby increasing the load resistance of the hydrostatic gas bearing incorporating the gas throttling structure, i.e., the load capacity of the hydrostatic gas bearing, and achieving the following effects unique to the present invention.
That is, the numerous gas throttle layers stacked from the upstream side to the downstream side of the tubular gas flow path are each composed of a pipe wall portion which forms the tubular gas flow path and numerous rib portions which are bridged to the inner wall surface of this pipe wall portion and formed integrally therewith, the rib portions of the gas throttle layer divide and block the flow path cross section of the pipe wall portion of the gas throttle layer in parallel at a predetermined rib arrangement interval, the gas throttle layer is integrated with adjacent pipe wall portions and rib portions along the tubular gas flow path, and the rib portions of adjacent gas throttle layers are arranged in different bridging directions between adjacent gas throttle layers, so that numerous fine flow paths are formed within the gas throttle structure and the gas throttle structure functions as a pseudo-porous structure to realize surface air supply into the bearing clearance, and the air permeability of the gas throttle structure can be easily adjusted simply by adjusting the rib arrangement interval of the rib portions or the number of gas throttle layers stacked.

According to the gas throttle structure of the invention of claim 2, in addition to the effect of the gas throttle structure of the invention of claim 1, the gas throttle layer provided on the outermost surface facing the supported object has a connecting portion that connects the rib portion at a predetermined interval, the total flow path cross-sectional area of the gas throttle layer provided on the outermost surface is smaller than the total flow path cross-sectional area of the gas throttle layer other than the gas throttle layer provided on the outermost surface, the pipe wall portion of the gas throttle layer provided on the outermost surface is integrated with the pipe wall portion of the gas throttle layer adjacent to the gas throttle layer provided on the outermost surface, and the connecting portion of the gas throttle layer provided on the outermost surface is integrated with the rib portion of the gas throttle layer adjacent to the gas throttle layer provided on the outermost surface, so that the amount of gas passing through the gas throttle layer provided on the outermost surface is smaller than the amount of gas passing through the gas throttle layer other than the gas throttle layer provided on the outermost surface, and since it functions like a surface clogging in a porous throttle, it is possible to suppress the occurrence of the self-excited vibration phenomenon in which the supported object vibrates due to the compressibility of the gas.

According to the hydrostatic gas bearing of the invention of claim 3, the gas throttling member has the gas throttling structure described in claim 1 or claim 2, so that the gas throttling member functions as a pseudo-porous member, and the air permeability of the gas throttling member can be easily adjusted simply by adjusting the rib arrangement spacing of the rib portion or the number of gas throttling layers.

According to the hydrostatic gas bearing of the invention of claim 4, in addition to the effect of the hydrostatic gas bearing of the invention of claim 3, the outlet surface of the gas throttling member is flush with the surface of the base plate or is recessed from the surface of the base plate, so that the outlet surface of the gas throttling member is less likely to come into contact with the supported object, and damage to the gas throttling member can be prevented.

1 is a perspective view of a hydrostatic gas bearing according to an embodiment of the present invention; Cross-sectional view of FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1 , showing a cross-sectional structure of the base plate; FIG. 2 is a perspective view of the gas throttle member shown in FIG. 1 . FIG. 2 is a plan view of the gas throttle member shown in FIG. 1 . 6 is a cross-sectional view taken along the line VI-VI of FIG. 5 . FIG. 2 is a schematic diagram illustrating a laminated state of a gas throttle structure for a hydrostatic bearing according to one embodiment of the present invention. FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. IX-IX cross-sectional view of FIG. 5 .

The present invention is a gas throttle structure for a hydrostatic gas bearing formed in a tubular gas flow path and facing a supported object, in which a number of gas throttle layers are laminated from the upstream side to the downstream side of the tubular gas flow path, each of which is composed of a pipe wall portion that forms the tubular gas flow path and a number of rib portions that are bridged and integrally formed with the inner wall surface of this pipe wall portion, the rib portions of the gas throttle layer divide and block the flow path cross section of the pipe wall portion of the gas throttle layer in parallel at a specified rib arrangement interval, the gas throttle layer is integrated with adjacent pipe wall portions and the rib portions along the tubular gas flow path, the rib portions of adjacent gas throttle layers are arranged in different bridge directions between adjacent gas throttle layers, and the specific embodiment can be any as long as it is possible to easily adjust the air permeability while realizing surface air supply into the bearing gap.

For example, the gas in the present invention may be any gas, but is preferably air.

For example, the material used to form the gas throttling structure of the present invention may be any material, such as resin, metal, ceramics, etc.

Below, a hydrostatic gas bearing 100 with a gas throttling structure, which is one embodiment of the present invention, will be described with reference to Figures 1 to 9.

1. Overview of hydrostatic gas bearing 100
First, an overview of an externally pressurized gas bearing 100 will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a perspective view of a hydrostatic gas bearing according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II--II of FIG.

As shown in FIG. 1, the hydrostatic gas bearing 100 includes a cylindrical base plate 110 and a resin gas throttle member 120 press-fitted into the base plate 110 .
In addition, a joint J is attached to the base plate 110 for connecting to an air pipe T connected to an air supply source.

Therefore, compressed air G supplied from an external air supply source passes through a tubular gas flow path formed by the base plate 110 and the gas throttling member 120, as shown in Figure 2, and is ejected from the countless ejection holes formed in the gas throttling member 120.
Therefore, the hydrostatic gas bearing 100 provides surface air supply to the object to be supported.

<2. Base plate>
Next, the base plate 110 will be described with reference to FIGS.
FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, showing the cross-sectional structure of the base plate.

As shown in FIG. 1, the base plate 110 is composed of a cylindrical lower plate 111 and a cylindrical upper plate 112 placed on the lower plate 111 .
The lower plate 111 and the upper plate 112 are joined by a joining means (not shown) so that air does not leak between the lower plate 111 and the upper plate 112 .

The lower plate 111 has four air supply holes 111a formed at equal intervals on the side surface thereof. The air supply holes 111a are female threaded to be mated with the male threads of the joint J.
The lower plate 111 has four outlet holes 111b formed at equal intervals on the upper surface thereof.

The air supply hole 111 a extends toward the center of the lower plate 111 , and the air outlet hole 111 b extends vertically downward from the lower plate 111 .
The air supply hole 111 a and the outlet hole 111 b communicate with each other inside the lower plate 111 to form a lower flow passage 111 c which is a part of the tubular gas flow passage of the hydrostatic bearing 100 .
The air supply hole 111a therefore forms the inlet end of the tubular gas flow passage.

In the upper plate 112 , an outlet hole 112 a is formed at a position opposite to the outlet hole 111 b of the lower plate 111 . The outlet hole 112 a forms the outlet end of the tubular gas flow path of the hydrostatic gas bearing 100 .
The outflow hole 112a is a stepped hole extending vertically, formed from a large-diameter inlet portion 112a1 formed on the lower surface side of the upper plate 112 and a small-diameter outlet portion 112a2 formed on the upper surface side of the upper plate 112.
The diameter of the inlet portion 112a1 is larger than the diameter of the outlet hole 111b of the lower plate 111.

<3. Gas throttle member>
Next, the gas throttle member 120 will be described with reference to FIGS.

<3.1. External structure of gas throttle member>
First, the external structure of the gas throttle member 120 will be described with reference to FIGS.
4 is a perspective view of the gas throttling member shown in FIG. 1, and FIG. 5 is a plan view of the gas throttling member shown in FIG.

As shown in FIGS. 2 and 4, the gas throttle member 120 is a cylindrical member, and is inserted into an outflow hole 112 a formed in the surface of the base plate 110 .
The gas throttle member 120 is composed of a cylindrical small diameter portion 121 that is inserted into the outlet portion 112a2 of the outflow hole 112a, and a cylindrical large diameter portion 122 that is inserted into the inlet portion 112a1 of the outflow hole 112a.
Therefore, compressed air G flows into the gas throttle member 120 through the large diameter portion 122 and flows out through the small diameter portion 121 .

The diameter φs (see FIG. 4) of the small diameter portion 121 is slightly larger than the diameter Do (see FIG. 3) of the outlet portion 112a2 of the outflow hole 112a.
Further, the diameter φb (see FIG. 4) of the large diameter portion 122 is slightly larger than the diameter Di (see FIG. 3) of the inlet portion 112a1 of the outflow hole 112a.
Therefore, when inserting the gas throttling member 120 into the upper plate 112 , the gas throttling member 120 needs to be press-fitted into the upper plate 112 .
The gas throttling member 120 is press-fitted into the upper plate 112 so that air does not leak between the gas throttling member 120 and the outlet hole 112 a of the upper plate 112 .

When the gas throttle member 120 is press-fitted into the upper plate 112, the upper surface 122a of the large diameter portion 122 abuts against the inner upper wall 112a3 (see FIG. 3) of the outlet hole 112a of the upper plate 112, as shown in FIG.
Furthermore, when the gas throttling member 120 is press-fitted into the upper plate 112, the outlet surface 121a of the small diameter portion 121 is flush with the surface 112b of the upper plate 112, as shown in Figures 1 and 2, and faces the object to be supported.

<3.2. Internal structure of gas throttle member (gas throttle structure)>
Next, the internal structure of the gas throttling member 120, that is, the gas throttling structure according to one embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5, FIG. 7 is a schematic diagram explaining the layered state of a gas throttle structure for a hydrostatic bearing which is one embodiment of the present invention, FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6, and FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 5.
In FIG. 7, the pipe wall portion is omitted in order to clearly show the arrangement of the rib portion.

As shown in FIG. 6 , the gas throttle member 120 is formed with a cylindrical internal flow passage 123 which becomes part of the tubular gas flow passage of the hydrostatic bearing 100 .
The internal flow path 123 is a flow path extending vertically connecting the outlet surface 121a of the small diameter portion 121 and the lower surface 122b of the large diameter portion 122, and a gas throttling structure 124 is formed on the outlet side of the internal flow path 123 to throttle the gas that flows into the internal flow path 123.

As shown in FIG. 7, the gas restricting structure 124 is composed of multiple gas restricting layers 124a stacked from the upstream side (lower surface 122b of the large diameter section 122) of the internal flow passage 123 toward the downstream side (outlet surface 121a of the small diameter section 121) and a gas restricting layer 124b provided on the outermost surface.

As shown in FIG. 8, the gas restricting layer 124a is composed of a pipe wall portion 124a1 that forms the internal flow passage 123, and a rib portion 124a2 that is integrally formed by bridging the inner wall surface of this pipe wall portion 124a1.
As shown in FIG. 7, the rib portion 124a2 of the gas restricting layer 124a has a rectangular cross-sectional shape.
As shown in FIG. 8, the rib portions 124a2 of the gas restricting layer 124a divide and block the flow passage cross section of the pipe wall portion 124a1 of the gas restricting layer 124a in parallel at a predetermined rib arrangement interval L1.

The gas restricting layer 124b, which is provided on the outermost surface facing the supported object when press-fitted into the base plate 110, is made up of a pipe wall portion 124b1 (see FIG. 5) that forms the internal flow path 123, a rib portion 124b2 (see FIG. 7) that is integrally formed by bridging the inner wall surface of this pipe wall portion 124b1, and a connecting portion 124b3 that connects this rib portion 124b2 at a predetermined connection interval L2.

As shown in FIG. 7, the connecting portion 124b3 has a rectangular cross-sectional shape.
In this embodiment, the connection interval L2 of the connecting portion 124b3 is equal to the rib arrangement interval L1.
Therefore, the gas restricting layer 124b provided on the outermost surface is formed with a square-shaped ejection hole 124b4 whose four sides have lengths equal to the rib arrangement interval L1 (=connection interval L2) in a plan view.
Therefore, the total flow path cross-sectional area (the sum of the opening areas of the ejection holes 124b4) in the gas restricting layer 124b provided on the outermost surface is smaller than the total flow path cross-sectional area (the sum of the gaps formed by the rib portions 124a2) in the gas restricting layer 124a.
That is, the flow passage cross section of the pipe wall portion 124b1 in the outermost gas restricting layer 124b is more closed than the flow passage cross section of the pipe wall portion 124a1 in the gas restricting layer 124a other than the outermost gas restricting layer 124b.

Next, we will explain the relationship between adjacent gas-throttled layers 124a, and the relationship between the gas-throttled layer 124b provided on the outermost surface and the gas-throttled layer 124a adjacent to the gas-throttled layer 124b provided on the outermost surface.

As shown in Figs. 6 and 7, the gas restricting layers 124a adjacent to each other on the upstream and downstream sides face each other in the stacking direction.
As shown in FIG. 6, the adjacent gas restricting layers 124a facing each other on the upstream side and the downstream side are integrated with each other at the pipe wall portion 124a1 and the rib portion 124a2.
Furthermore, the rib portion 124a2 of the nth (=1, 2, 3, ...)th gas throttling layer 124a and the rib portion 124a2 of the (n+2)th gas throttling layer 124a extend in the same direction as shown in Figure 7, but the bridging positions in a planar view are shifted horizontally (in a direction perpendicular to the stacking direction).
In addition, the rib portions 124a2 of adjacent gas restricting layers 124a facing each other on the upstream and downstream sides are twisted relative to each other in the stacking direction (twisted by approximately 90 degrees in this embodiment), as shown in Figure 7, i.e., are arranged in different cross-linking directions between adjacent gas restricting layers 124a.

The gas restricted layer 124b provided on the outermost surface and the gas restricted layer 124a adjacent to the gas restricted layer 124b provided on the outermost surface also face each other in the lamination direction, as shown in Figs.
As shown in FIG. 6, the tube wall portion 124b1 of the gas restricting layer 124b provided on the outermost surface is integrated with the tube wall portion 124a1 of the gas restricting layer 124a adjacent to and facing the gas restricting layer 124b provided on the outermost surface.
In addition, the rib portion 124b2 of the gas restricting layer 124b provided on the outermost surface and the rib portion 124a2 of the gas restricting layer 124a adjacent to the gas restricting layer 124b provided on the outermost surface are also arranged twisted relative to each other in the stacking direction (twisted by approximately 90 degrees in this embodiment) as shown in Figure 7.
Therefore, in this embodiment, the connecting portion 124b3 of the gas restricted layer 124b provided on the outermost surface is disposed directly above the rib portion 124a2 of the gas restricted layer 124a adjacent to the gas restricted layer 124b provided on the outermost surface.
As shown in FIG. 6, the connecting portion 124b3 of the gas restricted layer 124b provided on the outermost surface is integrated with the rib portion 124a2 of the gas restricted layer 124a adjacent to and facing the gas restricted layer 124b provided on the outermost surface.

In this embodiment, the width w1 (see FIG. 8) of the rib portion 124a2 of the gas throttling layer 124a is equal throughout the entire layer, and is also equal to the width w2 (see FIG. 7) of the rib portion 124b2 and the connecting portion 124b3 of the gas throttling layer 124b provided on the outermost surface.

By forming the gas throttle structure 124 in this manner, countless micro flow paths C as shown in Figure 9 are formed inside the gas throttle structure 124, and the gas throttle structure of this embodiment becomes a gas throttle structure similar to that of a porous body.

3. Effects of the hydrostatic gas bearing 100
According to the hydrostatic gas bearing 100 having the gas throttling structure of this embodiment described above, the numerous gas throttling layers 124a (in this paragraph, the gas throttling layer 124b provided on the outermost surface is also included) laminated from the upstream side to the downstream side of the tubular gas flow passage (the lower flow passage 111c of the base plate 110, the outflow hole 112a, and the internal flow passage 123 of the gas throttling member 120) are each composed of a pipe wall portion 124a1 forming the tubular gas flow passage and numerous rib portions 124a2 formed integrally with and bridging the inner wall surface of this pipe wall portion 124a1, and the rib portions 124a2 of the gas throttling layer 124a form the flow passage of the pipe wall portion 124a1 of the gas throttling layer 124a. The cross section is divided in parallel at a predetermined rib arrangement interval and blocked, the gas restricting layer 124a is integrated with adjacent tube wall portions 124a1 and rib portions 124a2 along the tubular gas flow path, and the rib portions 124a2 of adjacent gas restricting layers 124a are arranged in different cross-linking directions between adjacent gas restricting layers 124a. As a result, a large number of fine flow paths C are formed within the gas restricting structure 124 and the gas restricting structure 124 functions as a pseudo-porous structure, so that the air permeability of the gas restricting structure 124 can be easily adjusted simply by adjusting the rib arrangement interval of the rib portions 124a2 or the number of layers of the gas restricting layers 124a.

In addition, since the total flow path cross-sectional area of the gas restricting layer 124b provided on the outermost surface is smaller than the total flow path cross-sectional area of the gas restricting layer 124a other than the gas restricting layer 124b provided on the outermost surface, the amount of gas passing through the gas restricting layer 124b provided on the outermost surface is smaller than the amount of gas passing through the gas restricting layer 124a other than the gas restricting layer 124b provided on the outermost surface, and this functions like surface clogging in a porous restrictor, making it possible to suppress the occurrence of the self-excited vibration phenomenon in which the supported object vibrates due to the compressibility of the gas.

In addition, because the outlet surface 121a of the gas throttling member 120 is flush with the surface 112b of the base plate 110, the outlet surface 121a of the gas throttling member 120 is less likely to come into contact with the supported object, thereby preventing damage to the gas throttling member 120.

<Modification>
Although the hydrostatic gas bearing 100 according to one embodiment of the present invention has been described above, the hydrostatic gas bearing of the present invention is not limited to the hydrostatic gas bearing 100 according to the above-described embodiment.

For example, in this embodiment, the gas throttling member was press-fitted into the outflow hole formed on the surface of the base plate, but as long as the gas throttling member is in close contact with the outflow hole after being inserted into the outflow hole and air does not leak from the gap between the gas throttling member and the outflow hole, the insertion form of the gas throttling member into the outflow hole may be any, and for example, the gas throttling member may be fixed to the outflow hole with an adhesive.

For example, in this embodiment, the gas throttle member that is press-fitted into the base plate is made of resin, but the material of the gas throttle member is not limited to resin as long as it can form a gas throttle structure.

For example, in this embodiment, the number of gas throttle members press-fitted into the base plate is not limited to four.
Furthermore, the number of air supply holes formed in the lower plate may be any number as long as it is the same as the number of gas throttle members press-fitted into the base plate.
Additionally, the locations of the air inlet and outlet holes in the bottom plate may be in any location.

For example, in this embodiment, the diameter Di of the inlet portion 112a1 of the outlet hole 112a of the upper plate 112 is larger than the diameter of the outlet hole 111b of the lower plate 111, but the diameter Di of the inlet portion 112a1 may be the same as the diameter of the outlet hole 111b or may be smaller than the diameter of the outlet hole 111b.

For example, in this embodiment, the outlet surface of the gas throttling member is flush with the surface of the base plate, but the outlet surface of the gas throttling member may be recessed from the surface of the base plate.
In this case, the outlet surface of the gas throttling member is less likely to come into contact with the supported object than when the outlet surface of the gas throttling member is flush with the surface of the base plate, so damage to the gas throttling member can be further prevented.

For example, in this embodiment, the cross-sectional shape of the rib portion of the gas throttling layer was rectangular, but the cross-sectional shape of the rib portion of the gas throttling layer may be any shape, such as circular.

For example, in this embodiment, the cross-sectional shape of the bridged portion of the gas restricting layer provided on the outermost surface was rectangular, but the cross-sectional shape of the bridged portion of the gas restricting layer may be any shape, such as circular.

For example, in this embodiment, the rib portions of the gas throttling layers adjacent to each other on the upstream and downstream sides are arranged twisted 90 degrees from each other in the stacking direction, but the twist angle between the rib portions of the gas throttling layers adjacent to each other on the upstream and downstream sides is not limited to 90 degrees and may be any twist angle.

For example, in this embodiment, the rib arrangement intervals of the rib portion of the gas throttling layer are equal, but the rib arrangement intervals of the rib portion of the gas throttling layer are not limited to this and do not have to be equal.

For example, in this embodiment, the connection interval of the connecting portion of the gas throttle layer provided on the outermost surface was equal to the rib arrangement interval of the rib portion, but the connection interval of the connecting portion of the gas throttle layer provided on the outermost surface is not limited to this.

REFERENCE SIGNS LIST 100: Hydrostatic gas bearing 110: Base plate 111: Lower plate 111a: Air supply hole 111b: Outlet hole 111c: Lower flow passage (tubular gas flow passage)
112: Upper plate 112a: Outlet hole (tubular gas flow passage)
112a1: inlet portion 112a2: outlet portion 112a3: plate inner upper wall 112b: surface

120: Gas throttle member 121: Small diameter portion 121a: Outlet surface 122: Large diameter portion 122a: Upper surface 122b: Lower surface 123: Internal flow passage (tubular gas flow passage)
124: Gas throttle structure 124a: Gas throttle layer 124a1: Pipe wall portion 124a2: Rib portion 124b: Gas throttle layer 124b1 provided on the outermost surface: Pipe wall portion 124b2: Rib portion 124b3: Connection portion 124b4: Jet hole

J: Joint T: Air pipe G: Compressed air C: Micro flow path

Do: Outlet diameter Di: Inlet diameter Φs: Small diameter diameter Φb: Large diameter diameter

L1: Rib arrangement interval L2: Connection interval w1: Rib width w2: Connection width

Claims (4)

A gas throttle structure for a hydrostatic gas bearing, which is formed in a tubular gas flow path and faces a supported object, comprising:
a plurality of gas throttle layers laminated from the upstream side to the downstream side of the tubular gas flow passage are each composed of a pipe wall portion forming the tubular gas flow passage and a plurality of rib portions bridged to an inner wall surface of the pipe wall portion to be integrally formed therewith;
The rib portion of the gas throttle layer divides and blocks the flow passage cross section of the pipe wall portion of the gas throttle layer in parallel at a predetermined rib arrangement interval,
the gas restricting layer is integral with the wall portion and the rib portion adjacent to each other along the tubular gas flow passage;
A gas throttling structure, characterized in that the rib portions of the adjacent gas throttling layers are arranged in different cross-linking directions between the adjacent gas throttling layers. a gas restricting layer provided on the outermost surface facing the support object has connecting portions that connect the rib portions at predetermined intervals,
The total flow path cross-sectional area of the gas throttle layer provided on the outermost surface is smaller than the total flow path cross-sectional area of the gas throttle layer other than the gas throttle layer provided on the outermost surface,
The tube wall portion of the gas throttle layer provided on the outermost surface is integrated with the tube wall portion of the gas throttle layer adjacent to and facing the gas throttle layer provided on the outermost surface,
2. The gas throttle structure according to claim 1, wherein a connecting portion of the gas throttle layer provided on the outermost surface is integrated with a rib portion of an adjacent gas throttle layer facing the gas throttle layer provided on the outermost surface. A hydrostatic gas bearing comprising: a base plate in which an air supply hole communicating with an air supply source and forming an inlet end of a tubular gas flow passage and an outlet hole forming an outlet end of the tubular gas flow passage are formed; and a gas throttle member inserted into and in close contact with the outlet hole formed in a surface of the base plate,
3. A hydrostatic gas bearing, wherein the gas throttling member has the gas throttling structure according to claim 1. The hydrostatic gas bearing according to claim 3, characterized in that the outlet surface of the gas throttling member is flush with the surface of the base plate or is recessed from the surface of the base plate.