JP2017194117A - Journal gas bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a journal gas bering which achieves vibration stability from low speed to high speed and loss reduction, causes extremely small bearing damage when starting operation is stopped, is easily manufactured at low costs, and is light-weight and a compact (a small outer diameter).SOLUTION: A journal gas bearing 100 includes: a ring foil 200; a bearing case 300 disposed at an outer periphery side of the ring foil 200; and a plate-like spring member 400 disposed between the ring foil 200 and the bearing case 300. The ring foil 200 has: a cylindrical body A210; and an axial split projection part 220. The bearing case 300 has: a cylindrical body B310; and an axial groove part 312. A stopper pin 320 restricts axial movement of the ring foil 200 and the bearing case 300.SELECTED DRAWING: Figure 1

Description

  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.

  Bearings that support the rotating shafts of high-speed rotating machines such as turbomachines, generators, and motors are required to have higher speed performance and loss reduction performance as the speed of the high-speed rotating machines increases. Bearings are roughly classified into bearings using lubricant as a lubricant and bearings using ball bearings.

  Since the bearing using the lubricating oil has a high viscosity, the friction loss accompanying rotation increases, which hinders speeding up. Further, since a pump, a cooler, a tank and the like for supplying lubricating oil are necessary, there is a disadvantage that the entire apparatus becomes large. Furthermore, leakage of the lubricating oil leads to contamination of the entire apparatus equipped with the rotating machine. In particular, food machinery, aquaculture, greenhouses, etc. will cause serious damage to products.

  In addition, for example, in a bearing using a ball bearing, it is necessary to increase the outer diameter of the bearing by the size of the ball with respect to the shaft diameter of the rotating shaft, and occupy a large outer diameter and volume of the rotating part of the rotating machine. Yes. In addition, when the bearing is damaged due to the ball breakage, the rotating shaft loses its support and moves greatly in the radial direction (shifts in position). There are cases in which a fixed part such as a casing is contacted and is severely damaged, and damage to the bearing often leads to a severe damage to the rotating machine. A slide bearing that has a higher rotating shaft support capability than a ball bearing and can be manufactured at a low cost is the same as 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 rotating shaft, it becomes difficult to control above the secondary natural frequency of the rotating shaft, and a magnetic body or coil as a bearing Is necessary, and advanced control software and devices are required, resulting in a high cost.

  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 as the gas bearing (see Non-Patent Documents 1 and 2). The static pressure type is a type of bearing that assists floating of the rotating shaft by feeding high-pressure gas from the outside into the bearing portion. On the other hand, the dynamic pressure type floats by using the surrounding fluid in the bearing itself.

  Typical examples of the dynamic pressure type bearing include a leaf foil type and a bump foil type developed by NASA. In both cases, it is said that the bearing case tends to be large, the spring structure for elastically supporting a foil called a leaf or bump is complicated, and it is said that it is difficult to manufacture one having a shaft diameter smaller than 30 mm. A hydrodynamic bearing developed by Capstone Corp. is different from the two in the structure, but this has a problem that it is difficult to process the groove for attaching the spring to the bearing case and the inner surface of the casing.

JP 2002-61645 A JP 2004-270904 A JP 2006-57652 A JP 2002-364463 A Special table 10-511446

Junichi Jugo, Gas Bearing Guidebook, Kyoritsu Publishing Seika Yoshimoto, Gas bearing (oil-free bearing), Turbomachinery, Vol. 32, No. 7, July 2004

  The present invention has been made in view of the above problems, and an object of the present invention is to realize vibration stability from low speed to high speed and to reduce loss, and bearing damage at the time of starting and stopping is extremely small, and low cost. It is an object of the present invention to provide a light and compact journal gas bearing that is easy to manufacture.

  As a result of further diligent investigation and research aimed at improving the performance of the gas bearing, the present inventors have newly installed a ring foil and a bearing case, and further 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 spring member disposed between the ring foil and the bearing case. And
The ring foil includes a cylindrical body A, and a plurality of axially-divided protrusions that are provided at a predetermined interval in the circumferential direction on the outer peripheral surface of the cylindrical body A, and that have a notch in the middle part.
A plurality of the bearing cases are provided on the inner surface of the cylindrical body B and the cylindrical body B so as to be fitted to the axially divided projections of the ring foil, and at positions corresponding to the notches of the ring foil. 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,
A stop pin corresponding to the axial length of the notch is inserted from the through hole into the notch with the axially divided protrusion of the ring foil and the axial groove of the bearing case fitted. Further, the present invention relates to a journal gas bearing in which movement of the ring foil and the bearing case in the axial direction is restricted.

In the journal gas bearing of the present invention, it is preferable that the cross-sectional shape of the ring foil projection and the groove of the bearing case is an inverted trapezoid whose base is a short side.
Further, the ring foil preferably has an axially inner peripheral groove on the inner peripheral surface of the cylindrical body A.
Furthermore, the plate-like spring member preferably includes a plurality of spring member bodies and a connection portion that connects the spring member bodies and that corresponds to the axial length of the notch portion of the ring foil. The spring member main body preferably includes a plurality of tongue portions each having a tongue formed by the separation grooves arranged in a staggered manner in the axial direction at a predetermined interval in the circumferential direction. It is more preferable to have a plurality of small tongue parts.

  The journal gas bearing of the present invention achieves vibration stability from low speed to high speed and a reduction in loss, so that the bearing damage at the time of starting and stopping is extremely small. Further, it is easy to manufacture at low cost, and it is possible to reduce the weight and size (small outer diameter).

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 which shows schematic structure of the ring foil which concerns on one Embodiment of this invention. It is a section perspective view showing the outline composition of the bearing case concerning one embodiment of the present invention. It is an expanded view before mounting | wearing which shows schematic structure of the plate-shaped spring member which concerns on one Embodiment of this 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 includes a ring foil, a bearing case disposed on the outer peripheral side of the ring foil, and a plate spring member disposed between the ring foil and the bearing case. The ring foil includes a cylindrical body A, and a plurality of axially divided 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 part, A plurality of the bearing cases are provided on the inner surface of the cylindrical body B and the cylindrical body B so as to be fitted to the axially divided projections of the ring foil, and at positions corresponding to the notches of the ring foil. 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 axially dividing projection portion of the ring foil and the axial direction of the bearing case The groove is engaged If the stop pin corresponding to the axial length of the notch is inserted from the through hole into the notch, 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 a rotating shaft of a rotary machine such as a gas turbine.

  Hereinafter, each component of the journal gas bearing of this invention is demonstrated concretely.

[Ring foil]
The ring foil includes a cylindrical body A and an axially divided protruding portion (hereinafter sometimes simply referred to as a divided protruding portion) provided on the outer peripheral surface of the cylindrical body A. A plurality of the divided protrusions are provided at predetermined intervals in the circumferential direction of the cylindrical body A, and have a notch at an intermediate part of the protrusion. A rotating shaft 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 rotating shaft rotates.

  As the shape of the cylindrical body A, it has an inner surface shape that can stably accommodate the rotation shaft, and is preferably a perfect circle or a circular shape close thereto.

  The cross-sectional shape of the divided protrusions provided on the outer peripheral surface of the cylindrical body A can be various shapes such as a rectangular shape, an arc shape, and a polygonal shape, but the base portion has an inverted trapezoidal shape with a short side. preferable. That is, it is preferable to have a shape that becomes wider as it moves away from the axial center side of the cylindrical body A in the radial direction. Although this division | segmentation protrusion part is inserted in the groove part of a bearing case, it can prevent that a ring foil remove | deviates inside a bearing case because cross-sectional shape is an inverted trapezoid shape.

  A plurality of the divided projections are provided in the circumferential direction (for example, three at regular intervals). Thereby, the vibration which a ring foil receives from a rotating shaft is disperse | distributed equally. As a result, the ring foil is prevented from being deformed by being pressed in a specific direction, and vibration stability and loss reduction can be achieved.

  There may be a plurality of notches in the divided protrusions. That is, the division | segmentation protrusion part may be divided | segmented into 2 or 3 or more. Moreover, it is preferable that a division | segmentation protrusion part has length (total) more than 1/2 of the axial direction length of the cylindrical body A from points, such as vibration stability, and has 2/3 or more length. Is preferred. Moreover, it is preferable that it is a projection part extended from the axial direction both ends of a cylindrical body.

  In addition, an axial 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 protrusion. By providing the inner circumferential groove on the inner circumferential surface, outside air can be taken in more effectively from the outside of the journal gas bearing by utilizing the space formed in the projection or the like.

  As a material for the ring foil (cylindrical body A and divided projections) having the above-described configuration, it is preferable to use a material that is resistant to rust and has high legal stability in order to prevent the occurrence of rust filling a 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 so as to be able to be fitted to the divided protrusion corresponding to the divided protrusion of the ring foil. Further, the axial groove portion has a through-hole penetrating to the outer peripheral surface of the cylindrical body B corresponding to the axial length of the notch portion at a position corresponding to the notch portion of the ring foil. This bearing case forms the housing of the journal gas bearing.

  As the shape of the cylindrical body B, it has a diameter that is slightly larger than that of the cylindrical body A of the ring foil, and like the cylindrical body A, it is preferably a perfect circle or a circular shape close thereto. For example, by providing a flange at the end of the cylindrical body B, the bearing case can be fixed to the machine 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 shape, arc shape, polygonal shape, etc. Various shapes can be used, but an inverted trapezoidal shape in which the base has a short side is preferable. That is, it is preferable to have a shape that becomes wider from the axial center side of the cylindrical body B in the radial direction. The ring groove split projection is inserted into the axial groove, but the cross-sectional shape is an inverted trapezoid, so that the ring foil can be prevented from coming off inside the bearing case.

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

  The bearing case includes 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 stop pin is preferably the same shape as the through hole, and is formed, for example, in a rectangular cross section. The height of the retaining pin is preferably designed to be approximately the same as the wall thickness of the cylindrical body B of the bearing case. The ring foil is restricted from moving in the axial direction by inserting and fixing a stop pin into the through hole from the outer periphery of the bearing case to fill the space. This prevents misalignment in the axial direction when the ring foil is mounted and prevents misalignment due to vibration caused by rotation of the rotating shaft. Further, a connecting portion of a plate spring member described later is fixed by the stop pin.

  As a material of the bearing case having such a configuration, it is preferable to use a material that is not easily rusted and has high legal stability in order to prevent the occurrence of rust and the like filling a narrow gap, and examples thereof include SUS304, SUS316, and Inconel material. be able to.

[Plate spring member]
The plate spring member is disposed between the ring foil and the bearing case. The plate-like spring member includes, for example, a plurality of spring member bodies and connection portions that connect the spring member bodies. The axial length of the connecting 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 caused by the rotation operation of the rotating shaft, etc. Deviation is prevented, and a stable rotational operation can be maintained.

  The spring member main body has, for example, a rectangular shape and covers a portion excluding the split projections and the cutouts of the ring foil. The spring member main body has a tongue formed by a separation groove (penetrated through), and when a flat plate-like spring member is curved and arranged along the outer peripheral surface of the cylindrical body A of the ring foil, It is preferable to have a tongue portion (a tongue portion that can be erected) that protrudes from the base portion of the cylindrical spring member body to the outer peripheral side (tangential direction), and in particular, the tongue portion is staggered in the axial direction. It is preferable that a plurality of tongue portions arranged so as to be alternately erected on the right and left 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 | substrate can press the outer peripheral surface of a ring foil, and moderate elasticity can be hold | maintained.

  Further, it is preferable that a plurality of small tongue parts separated by the separation groove are formed at the tip of the tongue part. The length of the separation groove forming the small tongue is preferably about 1/3 to 2/3 of the length of the separation groove forming the tongue. Thereby, small weak vibrations are suppressed by the spring force of the small tongue, and large strong vibrations are suppressed by the strong spring force of the tongue.

  As a material of the plate-like spring member having the above-described configuration, it is preferable to use a material that is not easily rusted and has high legal stability in order to prevent the occurrence of rust filling a narrow gap. For example, SUS304, SUS316, Inconel materials can be used.

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

  The journal gas bearing according to the present invention is configured such that the axially divided projection of the ring foil is fitted into the axial groove of the bearing case, and the plate spring member is wound between the ring foil and the bearing case. In addition, since it is fixed by a stop pin at a notch formed between the protrusions of the ring foil, it is strong against radial or axial vibration of the rotating shaft, and the rotational operation is stabilized. Therefore, the loss of the journal gas bearing can be reduced.

  Further, the journal gas bearing of the present invention is a so-called dynamic pressure type gas bearing that uses a fluid (gas) present around the bearing as a lubricant, and unlike a general bearing that uses lubricant as a lubricant, Auxiliary equipment such as supply pumps, tanks, and coolers are not required. Therefore, it is possible to reduce the size, weight, and cost of a device that requires a bearing. Also, in air conditioners and the like, the lubricating oil of the bearing used in the compressor enters the heat exchanger and adheres to the heat transfer surface, impairing the performance of the heat exchanger, but the journal gas bearing of the present invention is applied. By doing so, lubricating oil becomes unnecessary and it can prevent the performance of a heat exchanger from deteriorating.

  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 of the present embodiment is arranged on a ring foil 200, a plate spring member 400 arranged along the outer peripheral surface of the ring foil 200, and further on the outer peripheral 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 rotating shaft, and is supported by the bearing case 300 and the spring member 400. As shown in FIG. 2, the ring foil 200 includes a cylindrical body 210 and a plurality of protrusions 220 formed on the outer peripheral surface of the cylindrical body 210 along the axial direction. A notch 230 is formed between the protrusions 220.

  The protrusions 220 are formed corresponding to groove portions 311 of the bearing case 300 to be described later, and are extended in the axial direction and are formed at equal intervals along the circumferential direction. In addition, the protrusion 220 is formed in an inverted trapezoidal shape in cross section with the base (inner diameter side of the ring foil) having 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 in an intermediate portion of the ring foil 200 in the axial direction. 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 includes a groove portion 311 formed along the axial direction on the inner peripheral surface of the cylindrical body 310. A flange 313 is provided at the end of the cylindrical body 310.
As shown in FIG. 3, the groove 311 is formed in an inverted trapezoidal shape in cross section corresponding to 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 such groove portions 311 are formed at equal intervals along the circumferential direction corresponding to the protruding portions 220.

  In addition, a through hole 312 that penetrates to the outer peripheral surface of the bearing case 300 is formed in the groove portion 311 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 is formed by the groove 311, the through hole 312, and the notch 230 after the ring foil 200 is attached to the bearing case 300. By inserting the stop pin 320 into the space to be formed (see FIG. 1), the movement in the axial direction is restricted. The through hole 312 is fixed by pin holding (not shown) after inserting the set pin 320.

  The flange 313 is provided with a plurality of mounting screw holes 340, which are attached to a gas turbine or the like through the mounting screw holes 340.

[Plate-shaped spring member 400]
The plate spring member 400 is an elastic member provided between the ring foil 200 and the bearing case 300. The plate spring member 400 supports the ring foil 200 with an appropriate elastic force, can stably hold the rotating shaft at the center, and alleviates fluctuations in the force generated between the rotating shaft and the ring foil 200. To do.

  As shown in FIG. 4, the plate-like spring member 400 before mounting is composed of three spring member bodies 410 and four connection portions 420 and 430 provided at both ends of the spring member body 410. The lengths of the connecting portions 420 and 430 in the axial direction (left and right in the drawing) are substantially equal to the length of the notch 230 of the ring foil 200 in the axial direction, and the plate spring member 400 is connected to the ring foil 200 and the bearing case. When it is attached to 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 notch by a through groove 440, and a tongue 451 is formed. The tongue portions 451 are arranged in a zigzag shape in the axial direction so as to be alternately erected on the left and right with respect to the axial direction, and constitute a row of tongue portion groups 450. In this embodiment, five rows of tongue groups 450 are provided at a predetermined interval for one spring member main body 410. Each tongue portion 451 has two small tongue portions 452 formed by a separation groove 470 that divides the tip side of the tongue portion 451 by about 1/2.

Next, journal gas bearings according to other embodiments will be described.
The journal gas bearing of this example has the same configuration as the journal gas bearing according to the above-described embodiment except that the ring foil has a different shape. Therefore, only the ring foil which is a characteristic configuration of the present embodiment will be described, and description of other configurations will be omitted.

  As shown in FIG. 6, the ring foil 500 of this embodiment is common to the ring foil 200 described above 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. The ring foil 200 is different from the ring foil 200 in that the inner circumferential groove 530 is provided. By providing the inner peripheral groove 530 on the inner peripheral surface, outside air can be taken in more effectively from the outside of the journal gas bearing. For example, the rotary shaft and the ring foil 500 can be quickly combined in the initial rotation stage of the rotary shaft. Since an air layer is formed between the two, 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 low loss, and has high bearing load capacity.

100 Journal gas bearing 200 Ring foil 210 Cylinder (Cylinder A)
220 Protrusion (Axial split protrusion)
230 Notch 300 Bearing case 310 Cylinder (Cylinder B)
311 Groove part 312 Through-hole 313 Flange 320 Stop pin 340 Mounting screw hole 400 Plate spring member 410 Spring member main body 420 Connection part 430 Connection part (connection end part)
440 Through groove 450 Tongue group 451 Tongue part 452 Small tongue part 470 Separation groove 500 Ring foil with inner circumferential groove 510 Projection part 520 Notch part 530 Inner circumferential groove

Claims (6)

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 is
Cylindrical body A;
A plurality of axially divided projections provided on the outer circumferential surface of the cylindrical body A with a predetermined interval in the circumferential direction, and having a notch in the middle part;
Have
The bearing case is
Cylindrical body B;
A plurality of axially divided projections of the ring foil are provided on the inner peripheral surface of the cylindrical body B so as to be able to be fitted, 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
A stop pin corresponding to the axial length of the notch is inserted from the through hole into the notch with the axially divided protrusion of the ring foil and the axial groove of the bearing case fitted. The journal gas bearing is characterized in that the 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 ring foil protrusion and the groove of the bearing case is an inverted trapezoid whose base is a short side.   The journal gas bearing according to claim 1 or 2, wherein the ring foil has an axially inner peripheral groove on an inner peripheral surface of the cylindrical body A.   The plate-like spring member comprises a plurality of spring member main bodies and a connection portion that connects the spring member main bodies and that corresponds to the axial length of the notch portion of the ring foil. 4. The journal gas bearing according to any one of 3.   5. The spring member main body includes a plurality of tongue portions each having a tongue portion formed by separating grooves arranged in a staggered manner in the axial direction at predetermined intervals in the circumferential direction. Journal gas bearing.   The journal gas bearing according to claim 5, wherein the tongue portion has a plurality of small tongue portions at a tip thereof.