JPH07151139A - Dynamic pressure bearing - Google Patents

Abstract

PURPOSE:To enhance a damping property and enhance safety against abrasion and seize. CONSTITUTION:A plurality of divided bearing pads 2 are arranged in the circumference of a rotational shaft 1 which rotates at high speed. Elastomer (an elastic body) is stuck on the surface of the bearing pad 2 facing to the shaft 1, and a metal thin plate 4 is stuck thereon. The metal thin plate 4 has a column- shaped metal ingot 10, and the metal ingot 10 is loosely fit to a corresponding recess installed in the bearing pad 2 and can absorb the displacement of the elastomer 3. The bearing pad 2 is formed so that the vicinity of an inclined supporting point 9 is thick and the rest is thin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing applied to a rotary bearing of a high speed dabo machine such as a turbine or a compressor, and a damper mechanism applied to the dynamic pressure bearing.

[0002]

5 and 6 show an example of a conventional dynamic pressure bearing and a journal bearing with a damper.

In FIG. 5, a plurality of pads 02 are arranged around a shaft 01 which rotates at a high speed, and a soft metal such as white metal is lined 03 on the surface of the pads 02 in an oil bearing to prevent seizure. In addition, an elastomer may be used as the lining material 03 in order to improve the damping property.

Further, a damper material 04 such as an O-ring is mounted around the bearing housing 06 and is put in a casing for vibration isolation from the outside. Reference numeral 08 is a pivot disposed between the pad 02 and the bearing housing 06.

FIG. 6 shows a damper mechanism provided between the bearing pad 02 and the bearing housing 06. The vibration of the rotary shaft 01 is transmitted to the spring 5 via the pivot 08.
The elastic hysteresis loss of the damper material 04 is used for damping.

An elastomer is used for the damper material 04, and this allows the elastic member 010 which accompanies the vibration of the bearing pad 02.
It absorbs the vibration energy of. The damper performance is
It depends on the amount of elastic loss energy of the damper material. Reference numeral 07 is a damper receiving plate, 09 is a bolt, and 010 is a pivot nut.

[0007]

By the way, when the dynamic pressure bearing is used as a gas bearing, it is effective to use an elastomer for the lining because of its poor damping property.

However, elastomers generally have poor wear resistance and often poor thermal conductivity. Therefore, in a gas bearing that operates up to a clearance of about several microns, there is a problem that the bearing clearance shape changes significantly due to wear caused by contact between the shaft and the pad at the time of start / stop, resulting in performance deterioration.

Further, there is a problem that the local temperature is liable to rise during contact, and seizure damage is likely to occur.

Further, the performance of a damper mechanism using an elastomer such as rubber for the damper material is governed by the magnitude of the loss coefficient with respect to the storage spring constant of the elastomer.

In the rear damper type shown in FIG. 5, the elastomer needs to have a certain degree of rigidity from the viewpoint of holding the core. For this reason, when the thickness of the elastomer is reduced, a large squeeze allowance is required for the O-ring or the like. In addition, when using a seat, it is essential to split the housing in two.
The mass of the moving body is large, and a large adjustment allowance is required for the elastomer performance.

Further, in the method of providing between the bearing pad and the housing as shown in FIG. 6, the internal damping due to the compressive deformation of the elastomer participates in the damping action, so that there is a drawback that its size is limited.

As described above, in the conventional damper, the damper performance depends on the loss factor of the elastomer, and the rigidity of the elastic plate acts in parallel. The ratio will deteriorate.

It is an object of the present invention to provide a new dynamic pressure bearing that solves the above-mentioned problems of the prior art.

[0015]

As a structure for achieving the above object, a dynamic pressure bearing of the present invention has a plurality of divided bearing pads arranged around a rotary shaft and provided on the outside thereof. In a tilting pad journal bearing that is tiltably supported with respect to the housing, an elastic body (elastomer) is attached to the side of the pad facing the rotating shaft, and a thin metal plate is attached to the upper surface of the elastic body. It has a feature.

Further, the metal thin plate of the bearing is thickened at a position in the same phase as the tilt fulcrum of the pad to form a metal block, and a recess is formed in the pad so that the metal block can move in the radial direction inside the pad. It is also effective to provide them.

Further, a bearing or a bearing housing of the journal bearing of the journal bearing, which is formed by dividing a cylinder or a cylinder around the rotary shaft and supports the shaft, is elastically supported by the casing. In the mechanism, the bearing pad is supported by a pivot, and a conical portion is provided on the opposite side of the pivot provided at the center of a damper elastic plate whose both ends are supported by the damper receiving plate, and the damper receiving plate facing the conical portion. It is also possible to form a concave conical portion on the side and sandwich a thin plate of an elastomer (elastic body) between both conical portions.

Further, as a viscous damper mechanism, a viscous fluid is enclosed in a bag-shaped chamber which is easily deformed like a thin seat cushion,
It may be arranged at the bottom of a cylinder having a bottom area of approximately the same size, and a thin plate-shaped piston whose periphery is easily elastically deformed may be pressed against this.

[0019]

According to the dynamic pressure bearing of the present invention configured as described above, in many cases, by providing the metal thin plate on the elastomer attached to the side of the bearing pad facing the rotating shaft,
Although the abrasion resistance is improved, since the surface is made of metal, the abrasion resistant film or the solid lubricating film can be easily formed by a method such as sputtering.

Further, the strong contact between the shaft and the pad is in the vicinity of the inclined support point where the movement of the pad surface in the radial direction is restricted. Since the contact time is short, a metal block is provided near the contact point. The heat capacity can be locally increased to suppress the increase in average temperature and prevent seizure.

Further, since the damper portion is formed by the taper of the two conical portions facing each other, the radial rigidity of the damper is increased, so that the shear strain of the elastomer between the conical portions can be increased even if the damper material is thinned. It is a compact and highly damped damper.

Further, by making the bottom areas of the cylinder and the chamber the same, the chamber pushes back the peripheral portion of the piston in the direction opposite to the compression direction by the compression by the piston. At this time, the viscous fluid near the center of the chamber flows to the periphery to cause a squeeze action, and a damping force acts on the movement of the piston. On the other hand, when the piston is unloaded, the viscous fluid around the piston is returned to the center by elastic recovery of the piston, and the piston can be repeatedly operated.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a tilting pad journal bearing according to a first embodiment of the present invention.

In the figure, a plurality of divided bearing pads 2 are arranged around a rotating shaft 1 rotating at a high speed.
In the case of the present embodiment, three bearing pads 2 arranged inclinable in the housing 6 are provided with an elastomer 3 made of fluororubber, butyl rubber or the like on the surface facing the rotating shaft 1, and an inclined support is provided thereon. A metal thin plate 4 having a cylindrical metal ingot 10 made of Inconel or a copper alloy is attached to the point 9 in phase.

The metal block 10 is loosely fitted in the recess 11 provided in the corresponding bearing pad 2, and can absorb the displacement of the elastomer 3.

The bearing pad 2 can be thinned except for the vicinity of the supporting point, and not only the compression displacement with respect to the elastomer 3 but also the shear displacement due to a slight bending of the pad surface can be applied to obtain damping. . Reference numeral 15 is a detent, and 17 is a bolt.

The metal ingot 10 and the metal thin plate 4 may be joined by welding or may be machined to be integrally formed.

A second embodiment of the present invention will be described below with reference to FIG. 2. FIG. 2 shows a dynamic pressure journal bearing equipped with the damper mechanism of the present invention.

In FIG. 2, the bearing pad 2 arranged around the rotary shaft 1 forms a tilting pad bearing which is integrated with the pivot 8 and is tiltable with respect to the damper elastic plate 5 supported at both ends.

A conical portion 5'is provided on the back side of the pivot 8 of the damper elastic plate 5, and a concave conical portion 5 "is formed on the damper receiving plate 7 facing the pivot portion 5 'so that they are fitted to each other. ing.

The elastomer 4 is mounted on the conical portions 5 ', 5 "between the damper elastic plate 5 and the damper receiving plate 7.

The damper receiving plate 7 is rigidly connected to the bearing housing 6.

Due to the axial vibration, the bearing pad 2 moves in the radial direction, and the conical portion 5'of the damper elastic plate 5 causes the elastomer 4 to be simultaneously subjected to compressive deformation and shear deformation. Elastomer 4
Since it can be made thin, the rigidity against compressive deformation is increased, but loss elasticity due to shear strain is gained, so that the decrease in damping capacity can be suppressed.

Next, a third embodiment of the present invention will be described with reference to FIGS. 3 (a) and 3 (b) are structural and functional diagrams of the damper of the present invention, in which a chamber 16 in which a viscous fluid 17 is enclosed is arranged at the bottom of a cylinder 19 having the same bottom area, and a thin plate piston 15 is shown. Is in contact with this.

When a force is applied to the pivot portion 13, the piston 15 is deformed as shown in FIG. 3 (b), and this elastic recovery displaces the piston to the right. Reference numeral 14 is a guide portion of the piston.

FIG. 4 shows a dynamic pressure journal bearing to which the damper of the present invention is attached. A plurality of bearing pads 2 arranged on the outer periphery of the rotary shaft 1 are supported by tiltable pivots 13, respectively. The damper portions (consisting of 14, 15, 16 and the like) are directly connected to the inside of the housing 18. The chamber 16 may be made of high strength fiber or copper plate.

Although the embodiments of the present invention have been briefly described above, the present invention is not limited to these embodiments and can be modified in design within the scope of the technical idea of the present invention, and any of them can be applied to the present invention. Belong to the technical scope.

[0038]

According to the present invention, the following effects can be obtained. (1) According to the first and second aspects of the present invention, the excellent characteristics of the low dynamic friction of the dynamic pressure bearing, especially the dynamic pressure gas bearing, have improved damping property and safety against wear and seizure, and thus have high speed turbomachinery. It will be put to good use by the expansion of application to.

(2) According to the third aspect of the present invention, a compact damper mechanism having a good core holding property and a good assembling property can be provided, and particularly, the high speed performance of the dynamic pressure gas bearing in which the damping performance is apt to be insufficient. Is improved.

(3) According to the inventions of claims 4 and 5, the performance of the damper, which has conventionally depended on damping or the like peculiar to the material, can be adjusted by the viscous fluid amount or the like without changing the chamber size, and the damper with higher damping can be obtained. A structure can be provided. Moreover, since the viscous fluid exists only in the sealed chamber, it can be applied to oil-free gas bearings.
A high damping bearing system can be constructed.

[Brief description of drawings]

FIG. 1 is a sectional view of a dynamic pressure journal bearing according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a dynamic pressure journal bearing according to a second embodiment of the present invention.

3A and 3B are explanatory views of the operation of the damper mechanism according to the third embodiment of the present invention, in which FIG. 3A shows a state before the piston is deformed, and FIG.

4 is a sectional view of a journal bearing of the present invention using the damper mechanism of FIG.

FIG. 5 is a sectional view of a conventional dynamic pressure journal bearing.

FIG. 6 is a cross-sectional view of a conventional journal bearing with damper.

[Explanation of symbols]

 1 Rotating Shaft 2 Bearing Pad 3 Elastomer 4 Metal Thin Plate 5 Damper Elastic Plate 6 Housing 7 Damper Receiving Plate 8 Pivot 10 Metal Lump 11 Recess 13 Pivot 14 Piston Guide 15 Piston 16 Chamber 17 Viscous Fluid

Claims (5)

[Claims] 1. A tilting pad journal bearing in which a plurality of divided bearing pads are arranged around a rotary shaft, and the pads are tiltably supported with respect to a housing provided outside the pad. A dynamic pressure bearing characterized in that an elastic body (elastomer) is attached to the side facing the rotating shaft, and a thin metal plate is further attached to the upper surface thereof. 2. A thin metal plate is thickened at a position in the same phase as the tilt fulcrum of the pad to form a metal block, and a recess is provided in the pad so that the metal block can move in the radial direction inside the pad. The dynamic pressure bearing according to claim 1, wherein 3. A damper for elastically supporting a bearing pad or a bearing housing including the bearing pad of a journal bearing for supporting the shaft around the rotary shaft, the cylinder bearing being divided into the cylinder or the cylinder. In the mechanism, the bearing pad is supported by a pivot, and a conical portion is provided on the opposite side of the pivot provided in the center of a damper elastic plate whose both ends are supported by the damper receiving plate, and a damper receiving plate facing the conical portion. A dynamic pressure bearing characterized in that a concave conical portion is formed on the side and a thin plate of an elastomer (elastic body) is sandwiched between the conical portions. 4. A viscous damper mechanism comprising a thin bag-shaped chamber filled with viscous fluid, a cylinder and a piston for enclosing the chamber, and a piston head formed of a thin disk. . 5. A cylinder formed in a radial direction on the inner surface of the bearing housing, and a thin bag-shaped chamber filled with a viscous fluid inserted into the cylinder bottom of the cylinder.
A pivot that fits into the recess of the bearing pad at one end, and a piston composed of a disk-shaped piston head thinly formed toward the cylinder periphery at the other end are formed, and the piston head side is in contact with the chamber. Viscous damper mechanism for dynamic pressure bearings.