WO2016129092A1

WO2016129092A1 - Hydrostatic bearing

Info

Publication number: WO2016129092A1
Application number: PCT/JP2015/053913
Authority: WO
Inventors: 英嗣石丸
Original assignee: 川崎重工業株式会社
Priority date: 2015-02-13
Filing date: 2015-02-13
Publication date: 2016-08-18

Abstract

The present invention addresses the problem of providing a hydrostatic bearing (100, 200, 300) for which generation of unstable vibrations is limited. Said hydrostatic bearing (100, 200, 300) is provided with a cylindrical bearing member in which multiple through holes (110, 210, 310) are disposed at different positions in the circumferential direction and into which a rotating shaft (2) can be inserted. The hydrostatic bearing (100, 200, 300) is configured so that a previously pressurized lubricating fluid (20) is supplied to the through holes (110, 210, 310), the rotating shaft (2) is supported to rotate freely by the static pressure of the lubricating fluid (20), and bearing rigidity is anisotropic.

Description

Hydrostatic bearing

The present invention relates to a hydrostatic bearing that rotatably supports a rotating shaft by static pressure of a lubricating fluid, and more particularly, to a hydrostatic bearing applicable to a high-speed rotating machine.

Rotating machines such as turbines and compressors use various types of bearings such as plain bearings, rolling bearings, and magnetic bearings to support the rotating shaft. The plain bearing is further classified into a dynamic pressure type and a static pressure type.

A hydrodynamic bearing is generated due to the viscosity of a lubricating fluid film (liquid such as oil or gas such as air) interposed in the bearing gap when it is drawn into the wedge-shaped gap generated by the relative sliding movement of the rotating shaft and the bearing. The load is supported by pressure (dynamic pressure).

On the other hand, a hydrostatic bearing introduces a pre-pressurized high-pressure lubricating fluid into a gap between the rotating shaft and the bearing, and supports the load of the rotating shaft by the static pressure of the lubricating fluid. As a representative example of a hydrostatic bearing, as shown in FIG. 7, a cylindrical bearing member 402 into which a rotating shaft 401 is inserted is provided, and the bearing member 402 has a plurality of holes having the same hole diameter extending in the radial direction. There is known a hydrostatic bearing 400 in which through-holes 403 are arranged at equal intervals in the circumferential direction, and a lubricating fluid 404 having the same pressure is supplied to each through-hole 403.

By the way, with respect to radial bearings, in a dynamic pressure type bearing, when the rotational speed of the rotating shaft is increased, the vibration of the rotating shaft suddenly increases at a certain point. This vibration is a self-excited unstable vibration in which the rotating shaft swings in the rotation direction due to the dynamic pressure effect of the lubricating film rotating in the bearing. It is also known that hydrostatic bearings exhibit the same dynamic pressure effect as that of hydrodynamic bearings during high-speed rotation, and similarly cause unstable vibrations.

As a method for suppressing this unstable vibration, in a hydrostatic bearing, a lubricating fluid is supplied to a rotating shaft in a direction opposite to the rotating direction from a through hole inclined obliquely from the radial direction of the rotating shaft. There is known a method of suppressing swinging in the rotation direction. In addition, by increasing the diameter of the through hole located above the through hole located below and supplying a lubricating fluid with a greater pressure from the upper through hole to the rotating shaft oriented in the horizontal direction, A method is known in which the rotating shaft is intentionally decentered downward to suppress swinging of the rotating shaft.

Regarding the dynamic pressure type bearing, for example, in Patent Document 1, in the dynamic pressure type tilting pad bearing, by making the area of the pressure receiving surface of the pad located in the load direction larger than the area of the pressure receiving surface of the pad on both sides in the circumferential direction, A method is described in which unstable vibration is suppressed by reducing the bearing rigidity in the direction perpendicular to the load and increasing the anisotropy of the bearing rigidity.

JP 2012-149694 A

However, in the former method for hydrostatic bearings, since a plurality of oblique through holes are provided in the bearing, the processing is troublesome, and depending on the inclination of the through holes, the swinging force in the direction opposite to the rotational direction is applied to the rotating shaft. There was a risk of generating. In the latter method, through-holes with different diameters are machined in the bearing, which is cumbersome, and if the eccentricity of the rotating shaft is too large, the gap between the bottom surface of the rotating shaft and the bearing becomes very narrow. There has been a problem that the rotating shaft may come into contact with the bearing due to various vibrations.

Therefore, an object of the present invention is to provide a hydrostatic bearing (hereinafter referred to as “hydrostatic bearing”) that can more reliably suppress the occurrence of unstable vibration without causing such a problem.

In order to solve the above-described problems, the hydrostatic bearing according to the present invention is configured as follows.

According to the first aspect of the present invention, a bearing member is provided, and this bearing member is a cylindrical bearing member in which a plurality of through holes are arranged at different positions in the circumferential direction and into which a rotating shaft can be inserted. A hydrostatic bearing configured to supply a pre-pressurized lubricating fluid to the through-hole and to rotatably support the rotating shaft by a static pressure of the lubricating fluid, the hydrostatic bearing Is configured to have anisotropy in bearing rigidity.

In addition, the through holes may be arranged such that an interval between the through holes adjacent to each other in the circumferential direction at at least one position is different from the interval at at least one other position.

Preferably, the bearing member has a pair of first and second circumferential regions facing each other, and the number of the through holes arranged in the pair of first circumferential regions is equal to the pair of first circumferential regions. More than the number of the said through-holes arrange | positioned in a 2nd circumferential direction area | region, the hole diameter of each said through-hole is substantially the same.

More preferably, the bearing member further includes a fixing member fixed to an outer peripheral surface of the bearing member, and the fixing member has an annular groove communicating with each of the through holes, and the annular groove and the respective The lubricating fluid is supplied to the through holes, and the force that the rotating shaft receives from the lubricating fluid in the through holes in the pair of first and second circumferential regions is different.

Furthermore, the through hole may be configured such that the hole diameter of at least one through hole at a certain position is different from the hole diameter of at least one through hole at another position.

Preferably, the bearing member has a pair of first and second circumferential regions opposed to each other, and a hole diameter of the through hole disposed in the pair of first circumferential regions is the pair. The through-holes are larger in diameter than the through-holes arranged in the second circumferential region, and the respective through-holes are arranged at substantially equal intervals in the circumferential direction.

In addition, the bearing member may be provided with an external supply means that preliminarily pressurizes the lubricating fluid to a predetermined pressure, and a supply pressure of the lubricating fluid supplied to at least one through-hole disposed at a certain position. Adjusting means for adjusting the supply pressure of the lubricating fluid pressurized by the external supply means so as to be different from the supply pressure of the lubricating fluid supplied to the at least one through hole.

Preferably, the bearing member has an external supply means that pressurizes the lubricating fluid to a predetermined pressure in advance, and the bearing member has a pair of first and second circumferential regions facing each other, Supply pressure of the lubricating fluid supplied to the through-holes arranged in the first circumferential region of the lubricating fluid supplied to the through-holes arranged in the pair of second circumferential regions Adjusting means for adjusting the supply pressure of the lubricating fluid pressurized by the external supply means so as to be different from the supply pressure.

The hydrostatic bearing according to an aspect of the present invention is configured to have anisotropy in bearing rigidity so that the center of the rotating shaft forms an elliptical orbit when rotating at a high speed.

According to the second aspect of the present invention, there is provided a rotating machine including a hydrostatic bearing and the rotating shaft, and the bearing member is provided with a plurality of through holes arranged at different positions in the circumferential direction, and rotated. A cylindrical bearing member into which a shaft can be inserted is provided, a lubricating fluid pressurized in advance to the through hole is supplied, and the rotating shaft is rotatably supported by the static pressure of the lubricating fluid, The hydrostatic bearing is configured to have anisotropy in bearing rigidity.

Preferably, the rotating shaft is supported by a plurality of hydrostatic bearings, and the hydrostatic bearings differ in bearing rigidity obtained by superimposing circumferential bearing stiffness distributions of the hydrostatic bearings. It is configured to have directionality.

With the above configuration, according to the invention according to each claim of the present application, the following effects can be obtained.

According to the first aspect of the present invention, since the bearing rigidity is anisotropic, the rotating shaft is not easily encouraged to swing around the rotating shaft in the rotational direction even if the rotational speed of the rotating shaft is increased. An orbit (for example, an elliptical orbit) is drawn, and the number of rotations causing unstable vibration can be increased as compared with the conventional one. Therefore, the occurrence of unstable vibration can be suppressed more reliably.

According to the inventions according to claims 2 to 4, since the plurality of through holes are not arranged at equal intervals, the bearing rigidity can be made anisotropic. Therefore, the same effect as that of the invention according to claim 1 can be obtained.

According to the inventions according to claims 5 to 7, since the diameters of the plurality of through holes are not equal, the bearing rigidity can be made anisotropic. Therefore, the same effect as that of the invention according to claim 1 can be obtained.

According to the inventions according to

claims

8 and 9, since the external pressure for supplying the lubricating fluid to each through hole is not equal, the plurality of through holes can have anisotropy in bearing rigidity. Therefore, the same effect as that of the invention according to claim 1 can be obtained.

According to the tenth aspect of the present invention, since the bearing shaft is configured to have anisotropy in the bearing rigidity so as to draw an elliptical orbit at the time of high-speed rotation, even if the rotation speed of the rotation shaft is increased. The rotating shaft is not easily promoted in the rotational direction of the rotating shaft, and the number of rotations causing unstable vibration can be increased compared to the conventional case. Therefore, the occurrence of unstable vibration can be suppressed more reliably.

According to the eleventh aspect of the invention, since the rotating shaft is supported by the hydrostatic bearing having anisotropy in bearing rigidity, the occurrence of unstable vibration in the rotating machine is suppressed as in the first aspect. Can do.

According to the invention of claim 12, the plurality of hydrostatic bearings that support the rotating shaft are configured to have anisotropy in the bearing stiffness obtained by superimposing the circumferential bearing stiffness distributions of the plurality of hydrostatic bearings. Therefore, for example, when focusing on the bearing rigidity of a plurality of hydrostatic bearings as well as when focusing on the bearing rigidity of one hydrostatic bearing, the rotation speed can be increased even if the rotational speed of the rotating shaft is increased. The shaft draws a non-circular orbit (for example, an elliptical orbit) in which the rotation of the rotating shaft in the rotation direction is not easily promoted, and the number of rotations where unstable vibration is generated can be increased as compared with the related art.

1 is a partial cross-sectional perspective view showing a rotary machine to which a hydrostatic bearing according to a first embodiment of the present invention is applied. It is the side view and longitudinal direction sectional view which show the structure of the same hydrostatic bearing. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is sectional drawing similar to FIG. 3 regarding the hydrostatic bearing which concerns on 2nd Example of this invention. It is sectional drawing similar to FIG. 3 regarding the hydrostatic bearing which concerns on 3rd Example of this invention. It is a figure which compares the stability of the hydrostatic bearing which concerns on a prior art example and the 1st-3rd Example. It is sectional drawing which shows schematically the prior art example of a hydrostatic bearing.

Hereinafter, embodiments of a hydrostatic bearing according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 shows a hydrostatic bearing (hydrostatic bearing mechanism) 100 incorporated in a rotary machine 10 such as a machine tool. Other examples of the rotating machine 10 include a turbocharger, a turbine expander, and a turbine refrigerator. The rotating machine 10 has a solid cylindrical rotating shaft (shaft) 2. The rotary shaft 2 is supported by a hydrostatic bearing 100 so as to be rotatable about a central axis 101 passing through the center of the hydrostatic bearing 100. For example, when the rotary machine 10 is a horizontal steam turbine, the rotary shaft 2 has its central shaft 14 placed horizontally, and a rotary blade (not shown) for converting steam pressure into rotational force is attached to one end side thereof. It is done. FIG. 1 illustrates the case where the center axis 101 of the hydrostatic bearing 100 and the center axis 14 of the rotary shaft 2 are coaxial. However, the rotary shaft 2 has a static pressure when the center axis 14 is rotated. The center axis 101 of the bearing 100 may be slightly eccentric and swing around.

The hydrostatic bearing 100 has a hollow inner cylinder 102 and a hollow outer cylinder 104, and the inner cylinder 102 is inserted inside the outer cylinder 104. More specifically, the inner cylinder 102 has an inner diameter slightly larger than the outer diameter of the rotary shaft 2, and the rotary shaft 2 is supported so as to be rotatable about the central axis 101. The outer cylinder 104 has the same or substantially the same inner diameter as the outer diameter of the inner cylinder 102, and the inner cylinder 102 is supported inside the outer cylinder 104 so as not to rotate.

In order to fix the inner cylinder 102 to the inner side of the outer cylinder 104 without a gap, for example, shrink fitting (calcination) can be used. In this case, the outer cylinder 104 is heated and expanded to expand its inner diameter, the inner cylinder 102 is fitted into the expanded outer cylinder 104, and both are fixed in a cooled state (normal temperature state or use temperature state). Alternatively, the outer cylinder 104 may be divided into two divided cylinders along a plane including the central axis 101, and these divided cylinders may be assembled around the inner cylinder 102 and fixed.

In order to supply the lubricating fluid 20 (liquid or gas) to a gap (lubricating space) having a predetermined thickness formed between the inner peripheral surface of the inner cylinder 102 and the outer peripheral surface of the rotary shaft 2, A plurality of flow paths are formed in the cylinder 104. As shown in FIGS. 1 to 3, the inner cylinder 102 according to the embodiment is directed in a radial direction from the central axis 101 on a transverse section 109 that is at the center in the axial direction of the inner cylinder 102 and orthogonal to the central axis 101. A plurality of extending through holes 110 are formed.

As shown in detail in FIGS. 2A and 3, in the illustrated state, in the upper region and the lower region, a plurality of through holes 110 y are symmetrical to the vertical axis Y and constant in the circumferential direction. Are formed at an interval (angle) θ. Further, in the state shown in the drawing, a plurality of through holes 110x are formed in the left region and the right region, respectively, symmetrically with respect to the horizontal axis X and at a constant interval (angle) θ in the circumferential direction. . Further, in the state shown in the drawing, the inner cylinder 102 has a holeless region or a solid region where the through hole 110 is not provided between the upper region or the lower region and the left region or the right region. In the embodiment, the interval θ is set to 5 to 15 degrees. In the embodiment, the inner diameters of the through holes 110y in the upper region and the lower region are equal to the inner diameters of the through holes 110x in the left region and the right region, and the number of the through holes 110y in the upper region and the lower region is “6”. And the number of the through holes 110x in the right region is “2”, and the amount of the lubricating fluid 20 supplied from the top and bottom through the plurality of through holes 110y is supplied from the left and right regions through the plurality of through holes 110x. It is configured to be larger than the amount of the fluid 20.

As shown in FIGS. 1 and 2, the outer cylinder 104 has a through-hole 110 extending in a radial direction from the central axis 101 at a location located on the above-described cross section 109 in a state of being combined with the inner cylinder 102, and a through-hole. An annular groove manifold 114 is formed which communicates with the hole 110 and is continuous in the circumferential direction along the inner peripheral surface. Therefore, in a state where the outer cylinder 104 is combined with the inner cylinder 102, the inner cylinder through hole 110 communicates with the manifold 114 and the outer cylinder through hole 112 via the manifold 114.

As shown in FIG. 1, the lubricating fluid supply pipe 16 is connected to the outer cylinder through hole 112. The lubricating fluid supply pipe 16 is connected to a lubricating fluid supply source 18 that supplies pressurized lubricating fluid 20.

According to the hydrostatic bearing 100 configured in this way, the rotary shaft 2 is inserted inside the inner cylinder 102. In this state, a gap or a lubrication space (not shown) is formed between the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the inner cylinder 102. The lubricating fluid 20 supplied from the lubricating fluid supply source 18 is supplied to the manifold 114 through the outer cylinder through hole 112. The lubricating fluid 20 supplied to the manifold 114 is dispersed in the circumferential direction along the manifold 114, and is supplied to the bearing space through the inner cylinder through hole 110 communicating therewith.

The lubricating fluid 20 supplied to the bearing space from the inner cylinder through-hole 110 is applied to the central shaft 101 of the hydrostatic bearing 100 in the upper region and the lower region and the left region and the right region in the state shown in FIGS. The rotating shaft 2 is urged toward it. As described above, more through holes 110 are formed in the upper region and the lower region than in the left region and the right region, and the force Fy applied to the rotating shaft 2 from the up and down direction is applied to the rotating shaft 2 from the left and right direction. Since it is larger than Fx, the vertical bearing rigidity is higher than the horizontal bearing rigidity. As a result, the center of the rotating shaft 2 draws an elliptical locus. About self-excited vibration caused by the gap flow between the inner cylinder and the rotating shaft, the movement grows (self-excited vibration is promoted) when the rotating shaft makes a circular motion about the center of the inner cylinder On the other hand, it is known that when the rotating shaft moves elliptically with respect to the center of the inner cylinder, it is known that the rotating shaft becomes more stable (movement does not grow) than when it moves circularly. By drawing, not only normal rotation but also unstable vibration during high-speed rotation can be reduced.

(Second embodiment)
FIG. 4 shows the inner cylinder 202 of the hydrostatic bearing 200 according to the second embodiment. In the inner cylinder 202 of this embodiment, a large number of through-holes 210 extending in the radial direction are formed on the at least one cross section orthogonal to the central axis 101 with a constant interval in the circumferential direction. In the embodiment, 16 through holes 210 are formed at an angle of θ = 22.5 degrees. Hereinafter, for convenience of explanation or when necessary, a through hole in the 12 o'clock direction (Y-axis direction in the drawing) is denoted by reference numeral 210 (1), and 22.5 degrees clockwise from the through hole 210 (1). The through holes separated from each other are indicated by reference numerals 210 (2)... 210 (16). As shown in the figure, the inner diameters of the four through holes 210 (15) to 210 (3) in the upper region and the four through holes 210 (7) to 210 (11) in the lower region are the three through holes in the right region. The inner diameters of the holes 210 (4) to 210 (6) and the three through holes 210 (12) to 210 (14) in the left region are made larger. Although not shown, the outer cylinder 204 is the same as the outer cylinder 104 of the first embodiment.

According to the hydrostatic bearing 200 of the second embodiment configured as described above, the amount of the lubricating fluid 20 supplied from the vertical direction is larger than the amount of the lubricating fluid 20 supplied from the left and right regions, and the rotary shaft 2 is By being pressurized in the vertical direction, the rotating shaft 2 draws a non-circular orbit (for example, an elliptical orbit).

(Third embodiment)
FIG. 5 shows a hydrostatic bearing 300 according to the third embodiment. In this embodiment, the inner cylinder 302 has a plurality of through-holes 310 extending in the radial direction on the at least one cross section orthogonal to the central axis 101 with a constant interval in the circumferential direction. In the embodiment, 16 through holes 310 are formed at an angle of θ = 22.5 degrees. Hereinafter, for convenience of explanation or as necessary, a through hole in the 12 o'clock direction (Y-axis direction in the drawing) is denoted by reference numeral 310 (1), and 22.5 degrees clockwise from the through hole 310 (1). The through holes separated from each other are denoted by reference numerals 310 (2)... 310 (16). Unlike the second embodiment, each of the through holes 310 (1) to 310 (16) has the same inner diameter.

The outer cylinder 304 has an upper region through hole 310 (15) to 310 (3), a right region through hole 310 (4) to 310 (6), a lower region through hole on a cross section corresponding to the inner cylinder through hole 310. Four circumferentially extending grooves or manifolds 314 (15 to 15) that do not communicate with each other in the inner peripheral surface regions that respectively face 310 (7) to 310 (11) and the left region through holes 310 (12) to 310 (14) 3), 314 (4 to 6), 314 (7 to 11), 314 (12 to 14), and outer cylinder through holes 312 (15 to 3) and 312 (4 to 6) communicating with these four manifolds, respectively. , 312 (7 to 11), 312 (12 to 14) are formed. The through holes 312 (15 to 3), 312 (4 to 6), 312 (7 to 11), and 312 (12 to 14) are respectively provided with pressure adjusting mechanisms 316 (15 to 3) and 316 (4 to 6). , 316 (7 to 11) and 316 (12 to 14) are connected to the lubricating fluid supply source 18.

According to the hydrostatic bearing 300 of the third embodiment configured as described above, during operation, the lubricating fluid 20 supplied from the lubricating fluid supply source 18 has the pressure adjusted by the pressure adjusting mechanisms 316 (15 to 3), 316. (4 to 6), 316 (7 to 11), and 316 (12 to 14), and then the corresponding manifolds 314 (15 to 3), 314 (4 to 6), 314 (7 to 11), 314 (12-14) through the through holes 310 (15) -310 (3), 310 (4) -310 (6), 310 (7) -310 (11), 310 (12) -310 (14) Supplied to the bearing space.

In the present embodiment, the pressure after the adjustment is such that the pressure of the lubricating fluid 20 supplied from the upper region through holes 310 (15) to 310 (3) and the lower region through holes 310 (7) to 310 (11) is the right. The pressure of the lubricating fluid 20 supplied from the region through holes 310 (4) to 310 (6) and the left region through holes 310 (12) to 310 (14) is larger. The pressure of the lubricating fluid 20 supplied from the upper region through holes 310 (15) to 310 (3) and the pressure of the lubricating fluid 20 supplied from the lower region through holes 310 (7) to 310 (11) may be the same. , One may be larger than the other. However, the pressure of the lubricating fluid 20 supplied from the right region through holes 310 (4) to 310 (6) and the pressure of the lubricating fluid 20 supplied from the left region through holes 310 (12) to 310 (14) are the same. Preferably there is.

Therefore, according to the hydrostatic bearing 300 of the third embodiment, the amount of the lubricating fluid 20 supplied from the vertical direction is larger than the amount of the lubricating fluid 20 supplied from the left and right regions, and the rotary shaft 2 is applied in the vertical direction. As a result, the rotating shaft 2 draws a non-circular locus.

(Stability comparison)
The

hydrostatic bearings

100, 200, 300 according to the first to third embodiments and a plurality of inner cylinder through holes formed at equal intervals in the circumferential direction, and a lubricating fluid having a constant pressure is supplied from the plurality of inner cylinder through holes to the bearing space. The stability of the rotating shaft of the isotropic hydrostatic bearing (comparative example) configured to be supplied to the rotating shaft was examined using simulation. The result of the examination is shown in FIG. In FIG. 6, the horizontal axis represents the rotational shaft rotational speed, and the vertical axis represents the damping ratio. The damping ratio is an index indicating the vibration of the rotating shaft, with the + side representing a stable vibration region and the − side representing an unstable vibration region.

As is clear from this figure, in the isotropic hydrostatic bearing of the comparative example, the unstable vibration increases as the rotational speed increases, and falls from the stable region to the unstable region at a relatively low rotational speed N0. On the other hand, in the anisotropic hydrostatic bearings according to the first to third embodiments, the stable region is maintained up to relatively high rotational speeds N1, N2, and N3 (> N0).

(Other examples)
Although the first to third embodiments have been described above, the hydrostatic bearing of the present invention can be variously modified.

For example, in the first embodiment, the case of one-line air supply in which the inner cylinder through-holes 110 are formed on one transverse section 109 has been described, but two rows in which the inner cylinder through-holes 110 are formed on a plurality of transverse sections 109. It is good also as the above air supply. Also in the second and third embodiments, the inner cylinder through hole 110 may be formed on one or a plurality of cross sections 109.

Further, in the first to third embodiments, the number of inner cylinder through holes formed on each cross section can be appropriately changed. For example, in the first to third embodiments, the number of inner cylinder through holes provided in the upper region and the lower region, and the right region and the left region is not limited to the above example. Similarly, in addition to the number of inner cylinder through-holes, the size of the inner cylinder through-hole, the supply pressure of the lubricating fluid for each inner cylinder through-hole, and combinations thereof can be changed as appropriate. In short, what is necessary is just to be comprised so that bearing rigidity may have anisotropy. Further, in the first embodiment, the lubricating fluid supply pipe 16 may be directly connected to the inner cylinder 102. In this way, the outer cylinder 104 can be omitted. In the third embodiment, the manifolds 314 (15 to 3) and 314 (7 to 11) may be communicated with each other. Similarly, manifolds 314 (4-6) and 314 (12-14) may be in communication.

Furthermore, a single rotating shaft 2 may be supported at a plurality of locations using a plurality of hydrostatic bearings according to the present invention. In this case, anisotropy of a plurality of hydrostatic bearings is obtained by superimposing (adding) the circumferential bearing stiffness distribution of each of the plurality of hydrostatic bearings, that is, the bearing stiffness of the entire plurality of hydrostatic bearings. By having such a configuration, anisotropy can be imparted to the bearing rigidity as a whole of the plurality of hydrostatic bearings. Therefore, as in the case of paying attention to the bearing rigidity of one hydrostatic bearing, even if the number of rotations of the rotating shaft 2 is increased, the rotating shaft 2 is not easily promoted in the rotational direction of the rotating shaft 2. A circular orbit (for example, an elliptical orbit) is drawn, and the number of rotations causing unstable vibration can be increased as compared with the conventional one.

The hydrostatic bearing with the central axis oriented in the horizontal direction has been described above, but the embodiments described above can be applied to hydrostatic bearings with the central axis oriented in the vertical direction as well. In this case, when the rotary shaft oriented in the vertical direction is viewed from above, the parts or places appearing in the direction of 12 o'clock, 6 o'clock, 3 o'clock, 9 o'clock are the upper part, lower part, right side, left side of the above-described embodiment. Corresponds to the site or location shown in.

100: Hydrostatic bearing 102: Inner cylinder 104: Outer cylinder 109: Cross section 110: Inner cylinder through hole 110y: Upper area through hole, lower area through hole 110x: Left area through hole, right area through hole 112: Outer cylinder through Hole 114: Manifold 200: Static pressure bearing 202: Inner cylinder 210 (1) to 210 (16): Inner cylinder through hole 300: Static pressure bearing 302: Inner cylinder 304: Outer cylinder 310 (1) to 310 (16): Inner cylinder through holes 312 (15-3) to 312 (12-14): Outer cylinder through holes 314 (15-3) to 314 (12-14): Manifolds 316 (15-3) to 316 (12-14) : Pressure adjustment mechanism

Claims

A plurality of through-holes are disposed at different positions in the circumferential direction, and a cylindrical bearing member into which a rotating shaft can be inserted is provided. Lubricating fluid pressurized in advance is supplied to the through-holes, A hydrostatic bearing configured to rotatably support the rotating shaft by pressure,
The hydrostatic bearing is configured to have anisotropy in bearing rigidity.
The through-holes are arranged such that an interval between the through-holes adjacent to each other in a circumferential direction at at least one position is different from at least one of the intervals at another position. Item 4. The hydrostatic bearing according to item 1.
The bearing member has a pair of first and second circumferential regions facing each other, and the number of the through holes disposed in the pair of first circumferential regions is equal to the pair of second circumferential regions. 3. The hydrostatic bearing according to claim 2, wherein the number of the through holes arranged in the direction region is larger than the number of the through holes, and the diameters of the through holes are substantially the same.
A fixing member fixed to the outer peripheral surface of the bearing member;
The fixing member has an annular groove communicating with each through hole,
The lubricating fluid is supplied to the annular groove and the through holes, and the force that the rotating shaft receives from the lubricating fluid in the through holes in the pair of first and second circumferential regions is different. The hydrostatic bearing according to claim 3.
2. The static pressure according to claim 1, wherein the through hole is configured such that a hole diameter of at least one through hole at a certain position is different from a hole diameter of at least one through hole at another position. bearing.
The bearing member has a pair of first and second circumferential regions opposed to each other, and a hole diameter of the through hole disposed in the pair of first circumferential regions is the pair of second regions. 6. The hydrostatic bearing according to claim 5, wherein each of the through holes is arranged at substantially equal intervals in the circumferential direction, and the diameter of each of the through holes is larger than a diameter of the through hole arranged in a circumferential region.
A fixing member fixed to the outer peripheral surface of the bearing member;
The fixing member has an annular groove communicating with each through hole,
The lubricating fluid is supplied to the annular groove and the through holes, and the force that the rotating shaft receives from the lubricating fluid in the through holes in the pair of first and second circumferential regions is different. The hydrostatic bearing according to claim 6.
External supply means for pre-pressurizing the lubricating fluid to a predetermined pressure;
The supply pressure of the lubricating fluid supplied to at least one through hole arranged at a certain position is different from the supply pressure of the lubricating fluid supplied to at least one through hole arranged at another position, The hydrostatic bearing according to claim 1, further comprising an adjusting unit that adjusts a supply pressure of the lubricating fluid pressurized by the external supply unit.
External supply means for pre-pressurizing the lubricating fluid to a predetermined pressure;
The bearing member has a pair of first and second circumferential regions facing each other, and a supply pressure of the lubricating fluid supplied to the through-holes disposed in the pair of first circumferential regions is The supply pressure of the lubricating fluid pressurized by the external supply means is adjusted to be different from the supply pressure of the lubricating fluid supplied to the through holes arranged in the pair of second circumferential regions. The hydrostatic bearing according to claim 8, comprising adjusting means.
10. The hydrostatic bearing is configured to have anisotropy in bearing rigidity so that the center of the rotating shaft draws an elliptical orbit when rotating at a high speed. The hydrostatic bearing described in 1.
A plurality of through-holes are disposed at different positions in the circumferential direction, and a cylindrical bearing member into which a rotating shaft can be inserted is provided. Lubricating fluid pressurized in advance is supplied to the through-holes, A rotary machine comprising a hydrostatic bearing configured to rotatably support the rotating shaft by pressure, and the rotating shaft;
The rotary machine is characterized in that the hydrostatic bearing is configured to have anisotropy in bearing rigidity.
The rotating shaft is supported by a plurality of the hydrostatic bearings,
The plurality of hydrostatic bearings are configured to have anisotropy in bearing stiffness obtained by superimposing circumferential bearing stiffness distributions of the plurality of hydrostatic bearings. Rotating machine.
A rotary machine comprising the hydrostatic bearing according to any one of claims 1 to 9 and a rotary shaft.