WO2019049353A1

WO2019049353A1 - Journal gas bearing

Info

Publication number: WO2019049353A1
Application number: PCT/JP2017/032599
Authority: WO
Inventors: 栄人松尾
Original assignee: 株式会社アーカイブワークス
Priority date: 2017-09-11
Filing date: 2017-09-11
Publication date: 2019-03-14

Abstract

The present invention addresses the problem of providing a journal gas bearing which is lightweight and compact (small outer diameter), the journal gas bearing being configured so that vibration stability from low speed to high speed and a reduction in loss are achieved, damage to the bearing during start and stop is considerably reduced, and the bearing can be manufactured at low cost. This journal gas bearing (100) is provided with a ring foil (200), a bearing case (300) which is disposed on the outer peripheral side of the ring foil (200), and a plate-shaped spring member (400) which is disposed between the ring foil (200) and the bearing case (300). The journal gas bearing (100) is characterized in that the ring foil (200) has a circular cylinder body A (210) and an axially split protrusion (220), the bearing case (300) has a cylinder body B (310) and an axial groove (312), and the axial movement of the ring foil (200) and the bearing case (300) is restricted by a stopper pin (320).

Description

Journal gas bearing

The present invention relates to a bearing for supporting a rotating rotor (rotating shaft) of a high-speed rotating machine using air or gas as a lubricating medium.

With the increase in speed of high-speed rotating machines, bearings that support the rotating shaft of high-speed rotating machines such as turbomachines, generators, and motors are required to improve their speeding-up performance and loss reduction performance. Bearings are roughly classified into bearings using lubricating oil as a lubricant and bearings using ball bearings.

Since the bearings using lubricating oil have high viscosity, friction loss with rotation increases, which hinders speeding up. In addition, the pump needs a pump for supplying lubricating oil, a cooler, a tank and the like, which has a disadvantage that the entire apparatus becomes large. Furthermore, the leakage of the lubricating oil leads to contamination of the entire machine equipped with the rotary machine. In particular, food machinery, aquaculture, greenhouses, etc. will cause great damage to products.

Also, for example, in a bearing using a ball bearing, it is necessary to increase the bearing outer diameter by the size of the ball with respect to the shaft diameter of the rotary shaft, and occupy a large outer diameter and volume of the rotary part of the rotary machine There is. In addition, when the bearing is damaged due to the destruction of the ball, the rotating shaft loses its support and moves largely in the radial direction (displacement occurs), so the fixed parts of the rotating rotor (rotation shaft) There are cases in which a fixed part such as a casing is in contact and is severely damaged, and damage to the bearing often leads to a large damage to the rotating machine. A sliding bearing that has a higher rotational shaft support capacity than a ball bearing and can be manufactured at low cost is similar to a ball bearing.

There is a magnetic bearing as a bearing that does not use lubricating oil, but it is necessary to provide a magnetic body on the rotary shaft, control becomes difficult above the second-order natural frequency of the rotary shaft, magnetic body or coil as a bearing And the need for sophisticated control software and equipment, which is costly.

Furthermore, there is a gas bearing as a bearing that does not use lubricating oil, and there are a static pressure type and a dynamic pressure type gas bearing (see Non-Patent Documents 1 and 2). The static pressure type is a type of bearing in which high pressure gas is externally supplied to the bearing portion to help floating of the rotating shaft. On the other hand, in the dynamic pressure type, the bearing itself floats using surrounding fluid.

Representative of hydrodynamic bearings are leaf foil type and bump foil type developed by NASA. In both cases, the bearing case tends to be large, the spring structure for elastically supporting the foil called a leaf or a bump is complicated, and it is said that it is difficult to manufacture one having a shaft diameter smaller than 30 mm. There is a dynamic pressure type bearing developed by Capston as a structure different from the two, but it is a problem that it is difficult to process the groove to which the bearing case is attached and the inner surface shape of the casing.

Japanese Patent Application Laid-Open No. 2002-61645 Patent Document 1: Japanese Patent Application Laid-Open No. 2004-270904 Japanese Patent Application Laid-Open No. 2006-57652 Patent Document 1: Japanese Patent Application Laid-Open No. 2002-64643 10-511446

The present invention has been made in view of the above problems, and the object of the present invention is to realize vibration stability from low speed to high speed and reduction of loss, bearing damage at start and stop is extremely small, and low cost To provide a lightweight and compact (small outer diameter) journal gas bearing that is easy to manufacture.

As a result of intensive investigations and studies to improve the performance of the gas bearings, the present inventors have newly installed the ring foil and the bearing case, and are disposed between the ring foil and the bearing case. A new combination structure with a plate-like spring member has been found, and the present invention has been completed.

That is, the present invention is a journal gas bearing comprising a ring foil, a bearing case disposed on the outer peripheral side of the ring foil, and a plate-like spring member disposed between the ring foil and the bearing case. ,
The ring foil has a cylindrical body A and a plurality of axial dividing projections provided at predetermined intervals in the circumferential direction on the outer peripheral surface of the cylindrical body A and having a notch at an intermediate portion,
The bearing case is provided with a plurality of cylindrical bodies B and an inner peripheral surface of the cylindrical body B so as to be able to be fitted with the axially divided projections of the ring foil, and at positions corresponding to the notches of the ring foils. And an axial groove portion having a through hole penetrating to the outer peripheral surface of the cylindrical body B corresponding to the axial length of the notch portion,
In a state where the axially divided projection of the ring foil and the axial groove of the bearing case are engaged, a locking pin corresponding to the axial length of the cutout is inserted from the through hole into the cutout. And a journal gas bearing characterized in that axial movement of the ring foil and the bearing case is restricted.

In the journal gas bearing of the present invention, it is preferable that the cross-sectional shapes of the protrusion of the ring foil and the groove of the bearing case have an inverted trapezoidal shape in which the base is a short side.
The ring foil preferably has an axially inner circumferential groove on the inner circumferential surface of the cylindrical body A.
Furthermore, it is preferable that the plate-like spring member comprises a plurality of spring member bodies, and a connection portion connecting the spring member bodies and corresponding to the axial length of the notch portion of the ring foil. The spring member main body is preferably provided with a plurality of tongue portions in which tongue portions formed by the separation grooves are disposed in a staggered manner in the axial direction at predetermined intervals in the circumferential direction, and the tongue portions have their tips It is more preferable to have a plurality of small tongues.

The journal gas bearing according to the present invention can achieve vibration stability from low speed to high speed and reduction of loss, and there is very little bearing damage at the start and stop. In addition, it is easy to manufacture at low cost, and light weight and compact (small outside diameter) can be realized.

It is a section perspective view showing the outline composition of the journal gas bearing concerning one embodiment of the present invention. It is a perspective view showing a schematic structure of a ring foil concerning one embodiment of the present invention. FIG. 1 is a cross-sectional perspective view showing a schematic configuration of a bearing case according to an embodiment of the present invention. It is a developed view before wearing which shows a schematic structure of a plate-like spring member concerning one embodiment of the present invention. It is an enlarged view of the spring member main body in the plate-shaped spring member shown in FIG. It is a perspective view which shows schematic structure of the ring foil which concerns on other embodiment of this invention.

The journal gas bearing of the present invention comprises a ring foil, a bearing case disposed on the outer peripheral side of the ring foil, and a plate-like spring member disposed between the ring foil and the bearing case. The ring foil has a cylindrical body A, and a plurality of axial dividing projections provided at predetermined intervals in the circumferential direction on the outer peripheral surface of the cylindrical body A and having a notch at an intermediate portion, The bearing case is provided with a plurality of cylindrical bodies B and an inner peripheral surface of the cylindrical body B so as to be able to be fitted with the axially divided projections of the ring foil, and at positions corresponding to the notches of the ring foils. And an axial groove portion having a through hole penetrating to the outer peripheral surface of the cylindrical body B corresponding to the axial length of the notch portion, and the axial direction division protrusion portion of the ring foil and the axial direction of the bearing case Groove fitted In particular, as long as a stop pin corresponding to the axial length of the notch is inserted from the through hole into the notch and the axial movement of the ring foil and the bearing case is restricted. For example, it is a dynamic pressure type gas bearing that supports the rotating shaft of a rotating machine such as a gas turbine.

Hereinafter, each component of the journal gas bearing of the present invention will be specifically described.

[Ring foil]
The ring foil comprises a cylindrical body A and an axial dividing projection provided on the outer peripheral surface of the cylindrical body A (hereinafter sometimes referred to simply as the dividing projection). A plurality of division | segmentation protrusion parts are provided at predetermined intervals in the circumferential direction of the cylindrical body A, and have a notch part in the middle part of a projection part. The rotation axis is accommodated on the inner peripheral side of the cylindrical body A, and the inner peripheral surface of the ring foil (cylindrical body A) becomes a sliding surface when the rotation axis rotates.

As a shape of the cylindrical body A, it has an inner surface shape which can stably accommodate a rotating shaft, and it is preferable that it is a perfect circle or circular shape near it.

As a cross-sectional shape of the division | segmentation protrusion part provided in the outer peripheral surface of the cylindrical body A, although it can be set as various shapes, such as a rectangular shape, arc shape, polygonal shape, it is reverse trapezoidal shape whose base is a short side preferable. That is, it is preferable that it is a shape which becomes wide as it distances in the radial direction from the axial center side of the cylindrical body A. Although this division | segmentation protrusion part is inserted in the groove part of a bearing case, it can prevent that ring foil remove | deviates to the inner side of a bearing case because cross-sectional shape is reverse trapezoidal shape.

A plurality of split protrusions (for example, three at equal intervals) are provided in the circumferential direction. Thereby, the vibration which a ring foil receives from a rotating shaft is distributed equally. As a result, deformation of the ring foil due to being pressed in a specific direction can be prevented, and vibration stability and loss reduction can be achieved.

There may be a plurality of notches in the dividing projection. That is, the dividing projection may be divided into two or three or more. Further, from the viewpoint of vibration stability etc., the divided projection preferably has a length (total) of 1/2 or more of the axial length of the cylindrical body A, and has a length of 2/3 or more. Is preferred. Moreover, it is preferable that it is a projection part extended from the axial direction both ends of a cylindrical body.

Further, an axially inner circumferential groove can be formed on the inner circumferential surface of the cylindrical body A, and the inner circumferential groove is preferably formed at a position corresponding to the projection. By providing the inner circumferential groove on the inner circumferential surface, it is possible to more effectively take in the outside air from the outside of the journal gas bearing by utilizing the space formed in the projection and the like.

As a material of the ring foil (cylindrical body A and divided projection) having the above-mentioned configuration, it is preferable to use a material which is hard to rust and high in legal stability in order to prevent the occurrence of rust etc. filling the narrow gap. For example, SUS304, SUS316, inconel material etc. can be mentioned.

[Bearing case]
The bearing case has a cylindrical body B and an axial groove provided on the inner peripheral surface of the cylindrical body B. The axial groove is provided to be engageable with the dividing projection corresponding to the dividing projection of the ring foil. Further, the axial groove has a through hole penetrating to the outer peripheral surface of the cylindrical body B corresponding to the axial length of the notched portion at a position corresponding to the notched portion of the ring foil. The bearing case forms a housing for the journal gas bearing.

As the shape of the cylindrical body B, it is preferable that the cylindrical body A has a diameter larger than that of the cylindrical body A of the ring foil, and, like the cylindrical body A, be round or nearly circular. For example, by providing a flange at the end of the cylindrical body B, the bearing case can be fixed to the machine main body by a fixing member such as a screw or a screw.

The axial groove portion is provided on the inner peripheral surface of the cylindrical body B so as to be able to be fitted to the divided projection portion corresponding to the divided projection portion of the ring foil, and the cross-sectional shape thereof is rectangular, arced, polygonal or the like Although various shapes can be made, it is preferable that it is a reverse trapezoidal shape whose base is a short side. That is, it is preferable that it is a shape which becomes wide as it distances in the radial direction from the axial center side of the cylindrical body B. The divided projections of the ring foil are inserted into the axial grooves, but the cross sectional shape is an inverted trapezoidal shape, so that the ring foil can be prevented from coming off inside the bearing case.

Moreover, the through-hole penetrated to the outer peripheral surface of the cylindrical body B corresponding to the axial direction length of a notch part is provided in the axial direction groove part in the position corresponding to the notch part of ring foil. This through hole is preferably formed in the same shape as the notch of the ring foil, for example in the form of a rectangular cross-section (square hole). When the ring foil is arranged in the bearing case, the notch of the ring foil is arranged corresponding to the through hole, and a space is formed by the through hole, the groove and the notch. .

The bearing case comprises a stop pin inserted from the outer periphery of the bearing case in a space formed by the through hole, the groove and the notch. The shape of the locking pin is preferably the same as the through hole, and is formed, for example, in a rectangular shape in cross section. The height of the locking pin is preferably designed to be similar to the wall thickness of the cylindrical body B of the bearing case. The ring foil is restricted from axial movement by inserting and fixing the locking pin from the outer peripheral portion of the bearing case to the through hole and filling the space. Thereby, the positional displacement in the axial direction when the ring foil is attached is prevented, and the positional displacement due to the vibration caused by the rotation of the rotation shaft is prevented. Moreover, the connection part of the plate-shaped spring member mentioned later is fixed by this stop pin.

As a material of the bearing case having such a configuration, it is preferable to use a material which is hard to rust and has high legal stability in order to prevent the occurrence of rust etc. filling a narrow gap, for example, SUS304, SUS316, Inconel material etc. be able to.

[Plate-like spring member]
The plate-like spring member is disposed between the ring foil and the bearing case. The plate-like spring member comprises, for example, a plurality of spring member bodies and a connection portion connecting the spring member bodies. The axial length of the connection portion corresponds to the axial length of the notch portion of the ring foil, whereby the position of the plate-like spring member in the axial direction due to vibration or the like caused by the rotational movement of the rotation shaft Deviation is prevented and stable rotational movement can be maintained.

The spring member main body is, for example, rectangular, and is shaped to cover the ring foil except for the division projections and the notches. In the spring member main body, a tongue portion is formed by the separation groove (cut through), and when the flat plate-like spring member is arranged to be curved along the outer peripheral surface of the cylindrical body A of the ring foil, It is preferable to have a tongue portion (an erectable tongue portion) that protrudes from the base portion of the cylindrical spring member main body to the outer peripheral side (tangential direction), and in particular, the tongue portion is axially staggered in an axial direction. It is preferable that a plurality of tongue portions disposed so as to be able to stand alternately in the left and right directions with respect to the direction are provided at predetermined intervals in the circumferential direction. Thereby, while the tongue part group of a plate-shaped spring member presses the inner peripheral surface of a bearing case, a base can press the outer peripheral surface of ring foil, and can hold | maintain moderate elasticity.

In addition, it is preferable that a plurality of small tongues separated by a separation groove be formed at the tip of the tongue. The length of the separation groove forming the small tongue portion is preferably about 1/3 to 2/3 of the length of the separation groove forming the tongue portion. As a result, the small weak vibration is suppressed by the spring force of the small tongue, and the large strong vibration is suppressed by the strong spring force of the tongue.

As a material of the plate-like spring member having the above configuration, it is preferable to use a material which is hard to rust and has high legal stability, for example, SUS304, SUS316, in order to prevent the occurrence of rust etc. Inconel material etc. can be mentioned.

In the journal gas bearing of the present invention having the above configuration, when the rotating shaft starts to rotate, suction is generated in the gap between the rotating shaft and the ring foil, and the outside air is at the axial end of the ring foil. It is taken into the inside of the journal gas bearing from the opening. The taken-in outside air stays in the gap between the rotation axis and the ring foil to form an air layer. This air layer functions as a lubricant between the rotation axis and the ring foil.

The journal gas bearing of the present invention is configured such that the axial split projections of the ring foil are fitted in the axial grooves of the bearing case, and the plate-like spring member is wound between the ring foil and the bearing case. In addition, since it is fixed by the stop pin at the notch formed between the projections of the ring foil, it is strong against radial or axial swinging of the rotation shaft, and the rotational movement is stabilized. Therefore, the loss of the journal gas bearing can be reduced.

Also, the journal gas bearing of the present invention is a so-called dynamic pressure type gas bearing that uses fluid (gas) existing around the bearing as a lubricant, and unlike a general bearing that uses a lubricant as a lubricant, There is no need for accessories such as feed pumps, tanks and coolers. Therefore, it is possible to miniaturize, reduce the weight, and reduce the cost of the device required for the bearing. In air conditioners and the like, the lubricating oil of the bearings used in the compressor intrudes into the heat exchanger and adheres to the heat transfer surface, thereby impairing the performance of the heat exchanger, but the journal gas bearing of the present invention is applied As a result, no lubricating oil is required, and the performance of the heat exchanger can be prevented from being degraded.

Hereinafter, specific embodiments of the above-described journal gas bearing will be described with reference to the drawings.

FIG. 1 is a cross-sectional perspective view showing a schematic configuration of a journal gas bearing according to an embodiment of the present invention. As shown in FIG. 1, the journal gas bearing 100 according to the present embodiment includes a ring foil 200, a plate-like spring member 400 disposed along the outer circumferential surface of the ring foil 200, and further disposed on the outer circumferential side thereof. A bearing case 300 is provided.

Hereinafter, the ring foil 200, the bearing case 300, and the spring part 400 which comprise the journal gas bearing 100 are demonstrated concretely.

[Ring foil 200]
The ring foil 200 is a cylindrical member that supports the rotation shaft, and is supported by the bearing case 300 and the spring member 400. As shown in FIG. 2, the ring foil 200 has a cylindrical body 210 and a plurality of protrusions 220 formed along the axial direction on the outer peripheral surface of the cylindrical body 210. Notches 230 are formed between the protrusions 220.

The protrusions 220 are formed to correspond to the grooves 311 of the bearing case 300 described later, extend in the axial direction, and are formed at equal intervals along the circumferential direction. Moreover, the projection part 220 is formed in the cross sectional view reverse trapezoidal shape where the base (inner diameter side of ring foil) becomes a short side. Therefore, when the ring foil 200 is attached to the bearing case 300, the ring foil 200 is inserted from the end of the bearing case 300 so that the protrusion 220 is inserted into the groove 311 of the bearing case 300.

The notch 230 is formed at an axial middle portion of the ring foil 200. When the ring foil 200 is attached to the bearing case 300, a space is formed at the position where the notch 230 is formed.

[Bearing case 300]
As shown in FIG. 3, the bearing case 300 has a groove 311 formed along the axial direction on the inner peripheral surface of the cylindrical body 310. Further, a flange 313 is provided at an end of the cylindrical body 310.
As shown in FIG. 3, the groove 311 is formed in an inverted trapezoidal shape in cross section in correspondence with the shape of the protrusion 220. That is, the width on the outer peripheral surface side is formed larger than the width of the opening on the inner peripheral surface side. Three grooves 311 are formed at equal intervals along the circumferential direction corresponding to the protrusions 220.

Further, in the groove portion 311, a through hole 312 penetrating to the outer peripheral surface of the bearing case 300 is formed at a central position in the axial direction. The through hole 312 is formed in a shape corresponding to the notch 230 of the ring foil 200, and after the ring foil 200 is attached to the bearing case 300, the through hole 312 is formed by the groove 311, the through hole 312 and the notch 230. By inserting the locking pin 320 into the space to be inserted (see FIG. 1), axial movement is restricted. The through holes 312 are fixed by pin holding (not shown) after the locking pin 320 is inserted.

The flange 313 is provided with a plurality of attachment screw holes 340, and the attachment screw holes 340 attach to a gas turbine or the like.

[Plate-like spring member 400]
The plate-like spring member 400 is an elastic member provided between the ring foil 200 and the bearing case 300. The plate-like spring member 400 supports the ring foil 200 with a suitable elastic force, and can stably hold the rotation axis at the center while reducing the fluctuation of the force generated between the rotation axis and the ring foil 200. Do.

As shown in FIG. 4, the plate-like spring member 400 before mounting is constituted by three spring member main bodies 410 and four

connection portions

420 and 430 provided at both ends of the spring member main body 410. The axial length (in the left and right direction in the drawing) of the

connection portions

420 and 430 is substantially equal to the axial length of the notch portion 230 of the ring foil 200, and the plate spring member 400 has the ring foil 200 and the bearing case. When mounted between 300 and 300, it is disposed at the position of the notch 230.

As shown in FIGS. 4 and 5, the spring member main body 410 is provided with a cut by a through groove 440, and a tongue portion 451 is formed. The tongue portions 451 are disposed in a staggered manner in the axial direction and can be alternately provided to the left and right with respect to the axial direction, and constitute a row of tongue portions 450. In the present embodiment, five rows of tongue portions 450 are provided at predetermined intervals for one spring member main body 410. Further, in each tongue 451, two small tongues 452 are formed by separation grooves 470 which divide the tip end side of the tongue 451 by about 1⁄2.

Subsequently, a journal gas bearing according to another embodiment will be described.
The journal gas bearing of the present embodiment has the same configuration as the journal gas bearing according to the above-described embodiment except that the shape of the ring foil is different. Therefore, only the ring foil which is the characteristic composition of this embodiment is explained, and the explanation about other composition is omitted.

As shown in FIG. 6, the ring foil 500 of this embodiment is common to the above-described ring foil 200 in that it has a protrusion 510 and a notch 520 on the outer peripheral surface, but on the inner peripheral surface of the protrusion 510. It differs from the ring foil 200 in that it has an inner circumferential groove 530. By providing the inner circumferential groove 530 on the inner circumferential surface, the outside air can be more effectively taken in from the outside of the journal gas bearing, for example, the rotation shaft and the ring foil 500 in a short time at the initial stage of rotation of the rotation shaft. Since the air layer is formed between them, the rotation efficiency can be further improved.

The journal gas bearing of the present invention is useful in many industrial fields because it can be manufactured at low cost, has a low loss, and has a high bearing load capacity.

100 journal gas bearing 200 ring foil 210 cylinder (cylinder A)
220 Protrusions (axially divided protrusions)
230 Notched part 300 Bearing case 310 Cylindrical body (cylindrical body B)
311 groove portion 312 through hole 313 flange 320 locking pin 340 mounting screw hole 400 plate spring member 410 spring member main body 420 connection portion 430 connection portion (connection end portion)
440 through groove 450 tongue group 451 tongue 452 small tongue 470 separation groove 500 ring groove with inner circumferential groove 510 protrusion 520 notched portion 530 inner circumferential groove

Claims

A journal gas bearing comprising a ring foil, a bearing case disposed on an outer peripheral side of the ring foil, and a plate-like spring member disposed between the ring foil and the bearing case,
The ring foil is
A cylindrical body A,
A plurality of axial division projections provided on the outer peripheral surface of the cylindrical body A at predetermined intervals in the circumferential direction and having a notch in the middle,
Have
The bearing case is
A cylindrical body B,
A plurality of axially split projections of the ring foil are provided on the inner peripheral surface of the cylindrical body B so as to be engageable with the ring foil, and the axial length of the notch is set at a position corresponding to the notch of the ring foil. A corresponding axial groove having a through hole penetrating to the outer peripheral surface of the cylindrical body B;
Have
In a state where the axially divided projection of the ring foil and the axial groove of the bearing case are engaged, a locking pin corresponding to the axial length of the cutout is inserted from the through hole into the cutout. A journal gas bearing characterized in that axial movement of the ring foil and the bearing case is restricted.
2. The journal gas bearing according to claim 1, wherein the cross-sectional shape of the projection of the ring foil and the groove of the bearing case is an inverted trapezoidal shape whose base is a short side.
The journal gas bearing according to claim 1 or 2, wherein the ring foil has an axially inner circumferential groove on the inner circumferential surface of the cylindrical body A.
The plate-like spring member comprises a plurality of spring member bodies and a connection portion connecting the spring member bodies, the connection portion corresponding to the axial length of the notch portion of the ring foil. 3. A journal gas bearing according to any of the three.
The spring member main body is provided with a plurality of tongue portions in which tongue portions formed by separation grooves are disposed in a staggered manner in the axial direction at predetermined intervals in the circumferential direction. Journal gas bearings.
6. A journal gas bearing as claimed in claim 5, characterized in that the tongue has at its tip a plurality of small tongues.