JP2016075324A - Thrust bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing capable of suppressing a top foil piece from contacting a thrust collar, and exhibiting a higher friction damping effect so as to be able to appropriately absorb the vibration and impact of a rotary shaft in the thrust direction.SOLUTION: A thrust bearing comprises: a top foil 10; a back foil 20; and a base plate 30. The back foil 20 is formed by a plurality of back foil pieces 21 arranged in the circumferential direction of the base plate 30, the top foil 10 is formed by a plurality of top foil pieces 11 arranged above the back foil pieces 21, respectively. A vibration damping foil piece 51 is disposed between each back foil piece 21 and each top foil piece 11. At least one circumferential side of each back foil piece 21 is radially divided into a plurality of sections and at least one circumferential side of the vibration damping foil 51 is radially divided into a plurality of sections.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a thrust bearing.

  Conventionally, as a bearing for a high-speed rotating body, a thrust bearing is known that is disposed to face a thrust collar provided on a rotating shaft. As such a thrust bearing, a foil-type thrust bearing, that is, a thrust foil bearing is well known. Thrust foil bearings are made of a flexible foil (thin metal plate) with a bearing surface that can absorb the movement of the rotating shaft (axial displacement and inclination of the thrust collar) caused by vibration and impact. A foil structure for flexibly supporting the bearing surface.

  As one form of such a thrust foil bearing, a bearing surface is formed by a plurality of ring pieces (ring piece) -shaped foil pieces (top foil pieces) obtained by dividing an annular plate in the circumferential direction. A structure in which each top foil piece is supported by a corrugated foil piece (bump foil piece) is known (for example, see Patent Document 1). Each top foil piece (having a thickness of about 100 μm) has an inclination angle with respect to the thrust collar, whereby a bearing gap between the thrust collar and the top foil piece is formed in a wedge shape in a side view. That is, the bearing gap is narrowed from the upstream side in the rotational direction of the thrust collar (rotating shaft) toward the downstream side. Therefore, when the thrust collar rotates from the side having the large bearing gap (upstream side) toward the side having the narrow bearing gap (downstream side), the lubricating fluid flows into the wedge and the load capacity is exhibited.

  The top foil piece is fixed to the base plate only at the upstream end of the thrust collar (rotating shaft) in the rotation direction. When the bearing load increases, the top foil is supported by the fixed side (upstream end) as a fulcrum. The maximum load capacity is generated when the inclination is relaxed to become horizontal and the inclination angle becomes about 0.1 °. On the other hand, the bump foil piece is arranged so that the ridge of the mountain is parallel to the downstream edge of the top foil piece, and only the edge of the bump foil piece on the downstream side in the rotation direction of the thrust collar (rotating shaft) is the base plate. It is fixed. That is, the upstream side edge is a free end.

  The bump foil piece is arranged / fixed in this way because the pressure of the fluid lubricating film generated on the top foil piece is increased on the narrow side (downstream side) of the bearing gap, and the portion is highly rigid. This is to increase the load capacity by supporting.

JP-A-10-331847

  By the way, in a rotating machine equipped with such a thrust bearing, when receiving a vibration or impact in the axial direction (thrust direction) of the rotating shaft, the rotating shaft vibrates in the thrust direction relative to the housing (casing). . As a means for attenuating the vibration of the rotating shaft against such vibrations and impacts, there is friction damping acting between the contact surfaces of the foils. That is, when the thrust collar of the rotating shaft pushes the top foil through the fluid lubricating film, the bump foil under the top foil is pushed in, and at that time, between the top foil and the bump foil or between the bump foil and the base plate. The movement is attenuated by the occurrence of sliding (friction).

  Further, in the thrust foil bearing structure described above, the bearing gap is narrowest on the downstream side end side of the top foil, and may reach submicron at high loads. Accordingly, contact with the thrust collar is likely to occur on the downstream end side, and when contact occurs, the top foil is worn and the bearing life is reduced, and in the worst case, seizure occurs. In order to avoid this, it is desirable to always keep the downstream edge of the top foil and the thrust collar parallel.

  However, in general, in the thrust foil bearing, the circumferential speed of the thrust collar on the outer peripheral end side is higher than the peripheral speed on the inner peripheral end side, so that the pressure (film pressure) of the fluid lubricating film increases on the outer peripheral end side. The pressure (membrane pressure) is low because the peripheral speed is slow on the inner peripheral end side. For this reason, although the outer peripheral end side of the top foil is pushed toward the bump foil side and moves away from the thrust collar, the inner peripheral end side rises to the thrust collar side and approaches the thrust collar.

  As a result, on the downstream side edge side of the top foil, the thickness of the fluid lubricating film on the inner peripheral edge side becomes extremely thin and cannot withstand a high load. Therefore, in the conventional thrust bearing, for example, as shown in Patent Document 1, the bump foil is divided into a plurality of pieces in the radial direction. That is, a slit is provided between the inner and outer bump foils, whereby the bump foil is divided into four parts from the inner peripheral side to the outer peripheral side, and the support force is changed more smoothly from the inner peripheral side to the outer peripheral side.

  However, even a thrust bearing in which such a bump foil is divided does not have a sufficient effect of attenuating the vibration of the rotating shaft with respect to the aforementioned vibration or impact, and the rotating shaft and the stationary part (housing) are brought into contact with each other. There is a fear. For example, when the rotating machine is a turbo machine, the impeller may rub the housing.

  The present invention has been made in view of the above circumstances, and an object thereof is to suppress the top foil piece from coming into contact with the thrust collar and exhibit a higher friction damping effect in the thrust direction of the rotating shaft. An object of the present invention is to provide a thrust bearing that can absorb vibrations and shocks satisfactorily.

  A thrust bearing according to the present invention is a thrust bearing disposed to face a thrust collar provided on a rotating shaft, the top foil being disposed to face the thrust collar, and the thrust collar of the top foil. A back foil disposed on a surface opposite to the surface opposite to the back foil, and an annular plate-shaped base plate disposed on a side of the back foil opposite to the top foil and supporting the back foil. The back foil is formed by a plurality of back foil pieces arranged in a circumferential direction of the base plate, and the top foil is formed by a plurality of top foil pieces respectively disposed on the back foil pieces. A damping foil piece is disposed between the back foil piece and the top foil piece, respectively. The back foil piece is divided into a plurality in the radial direction at least one side in the circumferential direction, and the damping foil piece is divided into a plurality in the radial direction at least one side in the circumferential direction. It is characterized by.

According to this thrust bearing, since the damping foil piece is disposed between the back foil piece and the top foil piece, the rotation shaft receives vibration and impact in the axial direction (thrust direction), and the top foil piece is When pushed into the thrust collar through the fluid lubricating film, sliding (friction) has conventionally occurred between the top foil and the back foil (bump foil). Slip (friction) occurs between the vibration foil piece and between the damping foil piece and the back foil piece. Therefore, by increasing the number of sites that generate frictional damping, a higher frictional damping effect can be achieved compared to the conventional case, and vibration and impact can be favorably absorbed in the thrust direction of the rotating shaft.
Moreover, since the back foil piece is divided into a plurality of pieces in the radial direction, the inner piece and the outer piece are operated independently, so that the top foil piece is pushed into the back foil piece side. The deformation of the back foil piece that occurs at the time becomes smooth in the radial direction, and therefore the support force by the back foil piece also changes more smoothly from the inner peripheral side toward the outer peripheral side. On the other hand, since the damping foil piece is also divided into a plurality of pieces in the radial direction, the divided pieces move independently corresponding to the divided pieces of the back foil, so that the movement of the individual divided pieces of the back foil piece can be reduced. Follow without resistance. Therefore, by dividing the back foil piece and the damping foil piece in the radial direction, the deformation in the radial direction of the top foil piece becomes smooth.

Further, in the thrust bearing, the back foil piece is divided into a plurality of parts in a radial direction on one side in the circumferential direction, and a continuous side continuous in the radial direction on the other side, and the damping foil piece Is characterized in that one side in the circumferential direction is divided into a plurality in the radial direction and the other side is a continuous side continuous in the radial direction.
According to this configuration, since the divided pieces of the back foil piece and the damping foil piece are integrated by the continuous side, the back foil piece and the damping foil piece can be easily fixed on the base plate. become.

Further, in the thrust bearing, the back foil piece is formed with a first slit between a plurality of back foil divided pieces divided in the radial direction, and the damping foil piece is divided in the radial direction. A second slit that overlaps the first slit is formed between the plurality of vibration-damping foil divided pieces.
According to this configuration, since the second slit between the damping foil divided pieces is formed so as to overlap the first slit between the back foil divided pieces, each of the damping foil divided pieces corresponds to the back foil divided piece. Follow the individual movements better.

Further, in the thrust bearing, the top foil piece has an end on the upstream side in the rotation direction of the rotating shaft serving as a top foil fixed side fixed to the base plate, and the damping foil piece The end on the upstream side in the rotational direction of the shaft or the end on the downstream side in the rotational direction is the continuous side, and the continuous side is fixed to the base plate together with the top foil fixing side of the top foil piece. It is characterized by.
According to this configuration, the top foil piece can be formed in the same manner as the conventional one without changing the shape of the top foil piece from the conventional one. In addition, since the continuous side of the damping foil piece is fixed to the base plate together with the fixed side of the top foil, the number of fixing points of the foil piece by spot welding etc. can be made the same as the conventional one, thus increasing the manufacturing cost. Can be suppressed.

Further, in the thrust bearing, the damping foil piece has an end side on the downstream side in the rotation direction of the rotating shaft as the continuous side, and the continuous side together with the top foil fixed side of the top foil piece, It is fixed to the base plate.
According to this configuration, since the damping foil piece is fixed to the base plate together with the top foil fixing side at the downstream continuous side, when the top foil piece is pushed into the thrust collar through the fluid lubricating film, The foil piece and the damping foil piece will slide in opposite directions, i.e. in opposite directions, thus increasing the relative slip between the top foil piece and the damping foil piece and higher friction. Attenuating effect is exhibited.
In the thrust bearing, the damping foil piece is formed of a damping alloy.
According to this configuration, in addition to frictional damping due to slippage between the foils, a damping effect due to bending deformation of the damping foil piece made of the damping alloy is also added, and thus a higher frictional damping effect is exhibited.

According to the thrust bearing of the present invention, the damping foil piece is disposed between the back foil piece and the top foil piece to increase the number of portions where friction damping occurs, so that a higher friction damping effect can be exhibited. Thus, vibration and impact can be favorably absorbed in the thrust direction of the rotating shaft.
In addition, the back foil piece and the damping foil piece are both divided in the radial direction to smooth the deformation in the radial direction of the top foil piece, so that the top foil piece is prevented from contacting the thrust collar locally. Accordingly, local wear of the top foil piece can be prevented, and the bearing life and seizure can be prevented.

It is a schematic diagram which shows an example of the turbomachine to which the thrust bearing which concerns on this invention is applied. It is a figure which shows 1st Embodiment of the thrust bearing which concerns on this invention, and is a side view of the thrust bearing of the state which pinched | interposed the thrust collar. 1 is a plan view of a first embodiment of a thrust bearing according to the present invention. It is a figure which shows 1st Embodiment of the thrust bearing which concerns on this invention, (a) is AA sectional view taken on the line in FIG. 3, (b) is a top view of a damping foil piece, (c) is bump A plan view of the foil piece, (d) is an explanatory view in which the plan view and the side view are made to correspond in order to explain the shapes of the damping foil piece and the bump foil piece. It is a top view of 2nd Embodiment of the thrust bearing which concerns on this invention. It is a figure which shows 2nd Embodiment of the thrust bearing which concerns on this invention, (a) is BB arrow sectional drawing of FIG. 5, (b) is a top view of a damping foil piece, (c) is bump A plan view of the foil piece, (d) is an explanatory view in which the plan view and the side view are made to correspond in order to explain the shapes of the damping foil piece and the bump foil piece. It is a figure which shows 3rd Embodiment of the thrust bearing which concerns on this invention, (a) is a top view of a thrust bearing, (b) is CC sectional view taken on the line of (a), (c) is vibration suppression. It is explanatory drawing which matched the top view and the side view, in order to demonstrate the shape of a foil piece and a bump foil piece.

Hereinafter, the thrust bearing of the present invention will be described in detail with reference to the drawings. In the following drawings, the scale of each member is appropriately changed to make each member a recognizable size.
FIG. 1 is a side view schematically showing an example of a turbo machine to which a thrust bearing of the present invention is applied. In FIG. 1, reference numeral 1 denotes a rotating shaft, 2 denotes an impeller provided at the tip of the rotating shaft, 3 Is a thrust bearing according to the present invention.

A thrust collar 4 is fixed to the rotary shaft 1 on the side where the impeller 2 is formed, and a pair of thrust bearings 3 is disposed on the thrust collar 4 so as to sandwich the thrust collar 4. .
The impeller 2 is disposed in a housing 5 on the stationary side, and has a tip clearance 6 between the impeller 2 and the housing 5.
The rotary shaft 1 is provided with a radial bearing 7 on the center side of the thrust collar 4.

  2, 3, and 4 (a) to 4 (d) are views showing a first embodiment of the thrust bearing 3 applied to the turbomachine having such a configuration, and FIG. 2 sandwiches the thrust collar 4. FIG. 6 is a side view of the thrust bearing 3 in a bent state. 3 is a plan view of the thrust bearing 3, FIG. 4A is a cross-sectional view taken along line AA in FIG. 3, FIG. 4B is a plan view of the damping foil piece, and FIG. 4B is a plan view of the bump foil piece, and FIG. 4D is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shapes of the damping foil piece and the bump foil piece.

  As shown in FIG. 2, in the first embodiment, the thrust bearing 3 </ b> A (3) is disposed on both sides of the thrust collar 4. The pair of thrust bearings 3 </ b> A (3) has the same configuration, and is an annular (cylindrical) one disposed opposite to the annular plate-like thrust collar 4 fixed to the rotating shaft 1. The rotation shaft 1 is extrapolated.

  The thrust bearing 3A includes a top foil 10 disposed to face the thrust collar 4, and a back foil 20 disposed to face a surface of the top foil 10 opposite to the surface facing the thrust collar 4. And an annular plate-like base plate 30 disposed on the side opposite to the top foil 10 side of the back foil 20, and a damping foil 50 is provided between the top foil 10 and the back foil 20. It is configured.

  In this embodiment, a cylindrical bearing spacer 40 indicated by a two-dot chain line is sandwiched between the base plates 30 of the pair of thrust bearings 3 </ b> A, and the base plate 30 is connected via the bearing spacer 40 by the fastening bolts 41. Has been. Further, the outer surface of one base plate 30 is fixed to the housing 5 by fastening bolts 41. Therefore, the pair of thrust bearings 3A, 3A is fixed to the housing 5 by fastening bolts 41 with the thrust collar 4 sandwiched therebetween. ing.

  As shown in FIG. 3, the base plate 30 is an annular plate and is made of metal, and has a plurality of through holes 42 (eight in this embodiment) through which the fastening bolts 41 are inserted. Yes. The base plate 30 is provided with a support region for supporting the back foil 20, the damping foil 50, and the top foil 10 on the surface on the thrust collar 4 side. In this embodiment, as will be described later, the back foil 20, the damping foil 50, and the top foil 10 are all formed by a plurality of (six) back foil pieces 21, damping foil pieces 51, and top foil pieces 11. Therefore, the base plate 30 is divided into six (equally divided into six) circumferential directions to form six support regions 31. However, in the present embodiment, these six support regions 31 are designed regions, and the surface of the base plate 30 that forms these support regions 31 is merely a flat surface.

As shown in FIG. 2, the back foil piece 21, the damping foil piece 51, and the top foil piece 11 are arranged and supported in this support region 31 in this order.
As shown in FIG. 3, the back foil 20 is formed by six back foil pieces 21 arranged in the circumferential direction of the base plate 30. These back foil pieces 21 are arranged on the respective support regions 31 of the base plate 30, and are thus arranged in the circumferential direction of the base plate 30. Further, these back foil pieces 21 are formed to be slightly smaller than the vibration damping foil pieces 51 and the top foil pieces 11 described later, so that they are not exposed to the thrust collar 4 side on the base plate 30 as shown in FIG. The top foil piece 11 and the damping foil piece 51 are covered.

  The back foil 20 composed of these back foil pieces 21 is formed of a foil (thin plate) and elastically supports the top foil 10 (top foil piece 11). Examples of the back foil 20 include a bump foil, a spring foil described in Japanese Patent Application Laid-Open No. 2006-57652 and Japanese Patent Application Laid-Open No. 2004-270904, and Japanese Patent Application Laid-Open No. 2009-299748. A back foil or the like is used. Note that the spring foil described in JP 2006-57652 A and JP 2004-270904 A and the back foil described in JP 2009-299748 A are foils used for radial bearings. If these are developed in a planar shape and formed into an annular plate shape, a foil used for a thrust bearing is obtained.

  In the present embodiment, as shown in FIGS. 3, 4A, 4C, and 4D, the back foil 20 is made of a bump foil, and therefore the back foil piece 21 is made of a bump foil piece. The bump foil piece (back foil piece) 21 is a foil (metal thin plate) having a thickness of about several hundreds μm formed into a corrugated plate by press molding, and as shown in FIG. It is formed in a substantially pentagonal shape close to the shape.

  As shown in FIG. 4D, the bump foil pieces 21 formed in the corrugated plate shape are alternately arranged with the valley portions 22 in contact with the base plate 30 and the peak portions 23 in contact with the top foil pieces 11. Is formed. Here, in the bump foil piece 21, the end side 21 a on the downstream side in the rotation direction of the rotation shaft 1 is a fixed side (bump foil fixed side) of the bump foil piece 21. The troughs 22 and the crests 23 are arranged in a direction orthogonal to the fixed side 21a (end side) of the bump foil piece 21, as shown in FIG. That is, the arrangement direction of the troughs 22 and the crests 23 is formed in a direction orthogonal to the fixed side 21a, so that the troughs 22 and the crests 23 extend in parallel with the fixed side 21a. Is formed.

  These valley portions 22 and peak portions 23 are formed at substantially equal pitches. Further, the height of the crest 23 is from the side opposite to the fixed side 21a toward the fixed side 21a, that is, on the downstream side in the rotational direction of the rotary shaft 1 (thrust collar 4) indicated by an arrow in FIG. It is formed so as to increase by a predetermined height as it goes. In addition, the outer peripheral side edge part on the opposite side to the fixed side 21a of the bump foil piece 21 is notched along the length direction of the trough part 22 as shown in FIG.4 (c).

  Further, the bump foil piece 21 is equally divided into four (plural) in the radial direction on one side in the circumferential direction, in this embodiment, the side opposite to the end side 21a on the downstream side in the rotation direction of the rotary shaft 1. The end side 21a (fixed side) on the other side is a continuous side that is continuous in the radial direction. Thus, the side opposite to the end side 21a is divided into four parts, so that the bump foil piece 21 is divided into four strip-like bump foil divided pieces 21b (back foil divided pieces) and fixed sides 21a (continuous sides). It is configured.

  A first slit 21c is formed between the four strip-shaped bump foil divided pieces 21b. In the present embodiment, the first slits 21 c are formed in an arc shape that forms a part of a circle concentric with the circle formed by the outer periphery of the bump foil piece 21. The widths of the first slits 21c are set such that the bump foil divided pieces 21b adjacent in the radial direction can move independently without interfering with each other. Since one side of the bump foil piece 21 is divided into four strip-shaped bump foil divided pieces 21b by the first slit 21c having such a width, the four strip-like bump foil divided pieces 21b are independently provided. It comes to move.

  Moreover, in this embodiment, when the peak parts 23 of the two bump foil division pieces 21b located on the outer peripheral side are compared with the peak parts 23 on the same row, the height of the top part is on the inner peripheral side. It is formed to be slightly higher than the peak portion 23 of the two bump foil division pieces 21b located. As a result, the bump foil piece 21 has a strong force for supporting the top foil piece 11 on the outer peripheral side and weaker on the inner peripheral side, and balances with the pressure of the fluid lubricating film. That is, since the pressure of the fluid lubricating film is high on the outer peripheral side of the top foil piece 11 and low on the inner peripheral side, the bump foil piece 21 relatively strongly supports the top foil piece 11 on the outer peripheral side, By supporting it weakly on the side, the force applied to the top foil piece 11 is balanced between the outer peripheral side and the inner peripheral side, and the top foil piece 11 is approximately equal to the bump foil piece 21 side on both the outer peripheral side and the inner peripheral side. It gets pushed.

  In addition, the bump foil piece 21 has a fixed side 21a at a position that substantially coincides with an end of the damping foil piece 51 or the top foil piece 11 described later on the downstream side in the rotation direction of the rotary shaft 1 in a plan view. Is arranged. The base plate 30 is spot welded (dot welded) and fixed along the direction of formation of the valleys 22 to be the end sides 21a.

At that time, since the end side 21a of the bump foil piece 21 is formed by one trough portion 22 that is continuous as a whole, the entire trough portion 22 can be easily welded. Therefore, the bump foil piece 21 can be easily fixed by welding.
The end side 21a can be fixed to the base plate 30 by, for example, screwing in addition to spot welding.

  The damping foil 50 is also formed by six damping foil pieces 51 arranged in the circumferential direction of the base plate 30 as shown in FIG. These damping foil pieces 51 are formed of a thin plate (foil) made of metal or alloy, but are preferably formed of damping alloy. As the damping alloy, a composite type, a ferromagnetic type, a dislocation type, and a twin type are known, but any of them can be used. Specifically, flake graphite cast iron (Fe—C—Si system), Cosmal-Z (Al—Zn system), etc. as composite types, TD nickel (Ni system), 13% chromium steel (Fe -Cr-based), Silantaloy (Fe-Cr-Al-based), Trunkalloy (Fe-Cr-Al-Mn-based), Gentaroy (Fe-Cr-Mo-based), NIVCO10 (Co-Ni-based), etc. as dislocation types KIXI alloys (Mn-Zr system), etc., are used as sonostone (Mn-Cu system), inlamute (Cu-Mn-Al system), nitinol (Ni-Ti system), etc. as twins. By producing the damping foil piece 51 with such a damping alloy, the damping foil piece 51 exhibits a damping function not only by sliding (friction) but also by deformation (bending deformation), and has a high damping effect. Come to play. Instead of these damping alloys, for example, a metal such as aluminum or copper may be used.

  Such a damping foil piece 51 is formed to have a thickness of about 1/5 to 1/2, specifically about 30 μm to 75 μm, with respect to the thickness of the top foil piece 11 described later. . By forming the thickness in such a range, the damping foil piece 51 has a good followability with respect to the top foil piece 11, thereby exhibiting a high friction damping effect. When the thickness of the damping foil piece 51 is less than 1/5 of the thickness of the top foil piece 11, the friction generated by rubbing between the top foil piece 11 and the bump foil piece 21 is reduced, and the friction damping effect is obtained. Decreases. Moreover, if it exceeds 1/2, the followability with respect to the top foil piece 11 will fall because the rigidity becomes high.

  Further, as shown in FIG. 4 (b), the outer shape of the damping foil piece 51 is formed in a substantially trapezoidal shape in which the inner peripheral side and the outer peripheral side are arc-shaped by cutting off the top side of the fan shape. Yes. Then, one side in the circumferential direction, in this embodiment, the downstream side in the rotational direction of the rotary shaft 1 is equally divided into four (plural) in the radial direction, and the fixed side 51a serving as the other side (upstream side in the rotational direction). Is a continuous side continuous in the radial direction. In this way, the side opposite to the fixed side 51a is divided into four parts, so that the damping foil piece 51 is composed of four strip-shaped damping foil divided pieces 51b and a fixed side 51a (continuous side). .

  A second slit 51c is formed between each of the four strip-shaped damping foil divided pieces 51b. In the present embodiment, the second slits 51c are formed in an arc shape that forms a part of a circle concentric with the circle formed by the outer periphery of the damping foil piece 51. The widths of the second slits 51c are set to dimensions that allow the damping foil split pieces 51b adjacent in the radial direction to move independently without interfering with each other. The second slits 51c are formed and arranged so as to overlap the first slits 21c of the bump foil pieces 21 as shown in FIG.

  Since one side of the damping foil piece 51 is divided into four strip-shaped damping foil split pieces 51b by the second slit 51c, the four strip-like damping foil split pieces 51b are independent of each other. It comes to move. Further, the four strip-shaped damping foil segment pieces 51b are placed in contact with the tops of the peaks 23 of the four strip-shaped bump foil segment pieces 21b, so that these four strip-shaped bump foil segment pieces 51b. The movement of the corresponding bump foil divided piece 21b in 21b is easily followed.

  The damping foil pieces 51 having such a shape are arranged on the support regions 31 of the base plate 30 so as to cover the bump foil pieces 21 and are arranged at equal intervals in the circumferential direction of the base plate 30 as a whole. The vibration damping foil 50 is formed by being arranged in a substantially annular plate shape.

  The damping foil piece 51 is formed to be slightly smaller than the support region 31 and slightly larger than the bump foil piece 21. Accordingly, the damping foil pieces 51 are arranged in the respective support regions 31 so as to cover the upper surfaces thereof without interfering with each other and without exposing the bump foil pieces 21 to the thrust collar 4 side. However, the present invention is not limited to this, and the damping foil piece 51 may be formed in the same size as the bump foil piece 21 or may be formed smaller than the bump foil piece 21.

  In addition, as described above, the damping foil piece 51 has an end on the upstream side in the rotation direction of the rotating shaft 1 (thrust collar 4) as a continuous fixed side 51a (continuous side), and the base plate 30 is formed by the fixed side 51a. It is fixed to. The fixing side 51 a is fixed to the base plate 30 by spot welding (dot welding), similarly to the end side 21 a of the bump foil piece 21.

  However, in this embodiment, as shown in FIG. 4A, the fixed side 51a is spot-welded to the base plate 30 together with the fixed side 12 of the top foil piece 11 described later. The fixed side 51a and the fixed side 12 can be fixed to the base plate 30 by, for example, screwing in addition to spot welding. Further, the damping foil piece 51 is bent at the downstream side in the rotation direction from the fixed side 51a, and is thereby raised so as to absorb the step corresponding to the height of the peak portion 23 of the bump foil piece 21, and is rotated in the rotation direction. The downstream side is placed on the peak portion 23 of the bump foil piece 21. On the other hand, the downstream side in the rotational direction is a free end that is supported on the peak portion 23 of the bump foil piece 21 without being fixed in the present embodiment.

  The top foil 10 is also formed by six top foil pieces 11 arranged in the circumferential direction of the base plate 30 as shown in FIG. These top foil pieces 11 are made of a thin metal plate (foil) having a thickness of about several hundreds μm, for example, about 150 μm. It is formed into a shape. That is, it is formed in the same size and shape as the damping foil piece 51. The top foil pieces 11 having such a shape are arranged on the respective support regions 31 of the base plate 30 so as to cover the damping foil pieces 51 and are arranged at equal intervals in the circumferential direction of the base plate 30 so as to be substantially circular as a whole. The top foil 10 is formed by arrange | positioning at annular plate shape.

  The top foil piece 11 is formed slightly smaller than the support region 31 as with the damping foil piece 51 and slightly larger than the bump foil piece 21. As a result, the top foil pieces 11 are arranged in the respective support regions 31 with their upper surfaces covered without interfering with each other and without exposing the bump foil pieces 21 and the damping foil pieces 51 to the thrust collar 4 side. Has been. However, the present invention is not limited to this. For example, the top foil piece 11 may be formed in the same size as the damping foil piece 51 or the bump foil piece 21, or the damping foil piece 51 or the bump foil may be formed. You may form smaller than the piece 21. FIG.

  Further, the top foil piece 11 has an end on the upstream side in the rotation direction of the rotating shaft 1 (thrust collar 4) as a fixed side 12, and is fixed to the base plate 30 by the fixed side 12. That is, the fixed side 12 is overlaid on the fixed side 51a of the damping foil piece 51 as shown in FIG. 4A, and fixed to the base plate 30 by spot welding (dot welding) together with the fixed side 51a. Has been. As a result, the welding point (fixed point) by spot welding can be made the same as in the conventional case where the damping foil piece 51 is not used, and therefore an increase in manufacturing cost can be suppressed.

  Further, as shown in FIG. 4A, the top foil piece 11 is bent on the downstream side in the rotational direction from the fixed side 12, thereby absorbing the height difference of the peak portion 23 of the bump foil piece 21. The bump foil piece 21 is placed on the peak portion 23 of the bump foil piece 21 so that it can be raised. On the other hand, the end side (trailing edge) on the downstream side in the rotational direction is a free end that is supported on the peak portion 23 of the bump foil piece 21 without being fixed, like the damping foil piece 51. Yes.

  In the present embodiment, the bump foil pieces 21 are arranged so that the valley portions 22 and the crest portions 23 are arranged in a direction orthogonal to the fixed side 21 a of the bump foil pieces 21 as described above. Therefore, the damping foil piece 51 and the top foil piece 11 are placed on the bump foil piece 21 so that the bump foil piece 21 is formed from the fixed side 51a and the fixed side 12 side along the arrangement direction of the ridges 23. As it goes to the fixed side 21a side, it is inclined and arranged at an initial inclination angle set by the peak portion 23 of the bump foil piece 21 so as to gradually move away from the inner surface of the base plate 30.

  Here, the initial inclination angle is an inclination angle of the top foil piece 11 with respect to the base plate 30 when the load is zero. Further, the inclination angle is an angle (gradient) θ determined by the height increase amount of the crest portion 23 of the bump foil piece 21 as shown in FIG. Therefore, when the load increases, the crest portion 23 of the bump foil piece 21 is pushed into the base plate 30 side and is flattened as a whole, so that the inclination angle θ becomes smaller than the initial inclination angle.

  In addition, the top foil piece 11 has a portion near the fixed side 12 as shown in FIG. 4A, that is, a portion located downstream of the fixed side 12 in the rotation direction of the rotary shaft 1. The thin portion 14 is formed thinner than the thin portion. The thin-walled portion 14 is formed in a straight line along the fixed side 12 and has a thickness of about 50% to 70% of the thickness (about several hundred μm) of other portions constituting the top foil piece 11. Is formed. Such a thin portion 14 can be formed by, for example, etching.

  Further, the thin portion 14 is formed so as not to reach the apex (ridgeline) of the peak portion 23 closest to the fixed side 12 among the peak portions 23 with respect to the bump foil piece 21 shown in FIG. ing. That is, the thin portion 14 is formed with its width set so as to be positioned between the fixed side 12 and the apex (ridge line) of the peak portion 23 on the fixed side 12 side. As a result, the top foil piece 11 is placed on all the crests 23 via the damping foil piece 51 other than the thin-walled portion 14 (other portions) so as to be evenly supported by these. Further, since the thin portion 14 is formed, the downstream side in the rotational direction can be inclined (inclined) more easily and smoothly than the thin portion 14. Furthermore, by forming such a thin portion 14, it is possible to increase the thickness of portions other than the thin portion 14 as compared with the conventional case.

Next, the operation of the thrust bearing 3A (3) having such a configuration will be described.
In the present embodiment, the thrust bearing 3A is provided on both sides of the thrust collar 4 as shown in FIG. By providing the thrust collar 4 on both sides in this way, the amount of movement in the thrust direction can be suppressed as much as possible. That is, by reducing the amount of thrust movement, the tip clearance 6 shown in FIG. 1 can be narrowed, thereby improving the fluid performance.

  In order to suppress the amount of movement in the thrust direction as much as possible, both thrust bearings 3A are installed close to the thrust collar 4 so that no large gap is generated. As a result, the top foil pieces 11 (top foil 10) of both thrust bearings 3A are slightly pressed against the thrust collar 4. At this time, since the thin portion 14 is formed on the top foil piece 11 in this embodiment, the downstream side (free end side) in the rotation direction is easy to be inclined (bend easily). Therefore, the pressing force is smaller than the pressing amount, thereby reducing the starting torque.

That is, conventionally, an inclination angle larger than the optimum angle is previously provided so that the inclination angle of the top foil piece becomes the optimum angle when the load increases. Accordingly, when the rotation is stopped, the top foil piece is in a pressed state (preloaded state) with the thrust collar 4 sandwiched from both sides. However, conventionally, since the thickness of the top foil piece is also constant, the pressing force (preload) to the thrust collar 4 is strong and the starting torque is large.
On the other hand, in this embodiment, since the thin part 14 is formed in the top foil piece 11 as described above, the starting torque is reduced.

  Further, when the rotation shaft 1 rotates and the thrust collar 4 starts to rotate, the thrust collar 4 and the top foil piece 11 rub against each other, and the surrounding fluid is pushed into the wedge-shaped space formed therebetween. When the thrust collar 4 reaches a certain rotational speed, a fluid lubricating film is formed between them. The top foil piece 11 (top foil 10) is pressed against the bump foil piece 21 (back foil 20) via the damping foil piece 51 (damping foil 50) by the pressure of the fluid lubricating film, and the thrust collar 4 is the top. The contact state with the foil piece 11 is released, and the foil piece 11 rotates without contact.

In this state, when a vibration or impact in the axial direction of the rotating shaft 1 acts as shown by an arrow in FIG. 2, the thrust collar 4 comes close to the top foil piece 11, thereby increasing the pressure of the fluid lubricating film, The foil piece 11 is further pushed into the bump foil piece 21 side.
At that time, friction is generated by sliding on the contact surface between the top foil piece 11 and the damping foil piece 51 and the contact surface between the damping foil piece 51 and the bump foil piece 21, whereby the top foil piece 11 is pushed. The movement is suppressed. Further, when the pushed-in top foil piece 11 returns to the original state, friction due to sliding occurs.

  Therefore, by generating heat by friction, kinetic energy such as vibration is converted into thermal energy and consumed, and a friction damping effect is obtained. Therefore, the possibility that the impeller 2 shown in FIG. 1 rubs the housing 5 is reliably avoided by the friction damping effect of the thrust bearing 3A.

  Further, when the pressure of the fluid lubricating film increases and the top foil piece 11 is pushed into the bump foil piece 21 side, the peripheral speed is high on the outer peripheral side of the top foil piece 11 and the pressure (film pressure) of the fluid lubricating film increases. Since the peripheral speed is low and the film pressure is low on the inner peripheral side, the outer peripheral portion of the top foil piece 11 is pushed toward the bump foil piece 21 side and tries to move away from the thrust collar 4, and the inner peripheral portion Tries to get up to the thrust collar 4 side.

  However, in the present embodiment, the bump foil piece 21 is divided into four at the inner and outer circumferences, and the height of the crest portion 23 of the inner bump foil divided piece 21b is lower than that of the outer bump foil divided piece 21b. Therefore, the force for supporting the top foil piece 11 is strong on the outer peripheral side and weak on the inner peripheral side, and therefore, balances with the pressure of the fluid lubricating film (the outer peripheral side is high pressure and the inner peripheral side is low pressure). As a result, the top foil piece 11 is pushed almost equally into the bump foil piece 21 on both the inner and outer peripheral sides, and the film thickness of the fluid lubricating film on the inner peripheral side at the downstream end side of the top foil piece 11 is extremely large. Thinning is suppressed, and the non-contact state between the top foil piece 11 and the thrust collar 4 is maintained even at a high load.

  Further, since the bump foil piece 21 is divided into four (plural) in the radial direction, the inner peripheral bump foil piece 21b and the outer bump foil piece 21b operate independently of each other. The deformation of the bump foil piece 21 that occurs when the top foil piece 11 is pushed into the bump foil piece 21 side becomes smooth in the radial direction, so that the supporting force by the back foil piece is also smoother from the inner circumference side toward the outer circumference side. To change. On the other hand, since the damping foil piece 51 is also divided into four (plural) in the radial direction, the damping foil divided piece 51b moves independently corresponding to the bump foil divided piece 21b. The divided pieces 51b follow the movement of the individual bump foil divided pieces 21b without resistance.

  In the thrust bearing 3A (3) of the present embodiment, the damping foil piece 51 is disposed between the bump foil piece (back foil piece) 21 and the top foil piece 11, respectively. When the top foil piece 11 is pushed into the thrust collar 4 through the fluid lubricating film due to vibration or impact in the direction (thrust direction), conventionally, it is between the top foil 10 and the back foil 20 (bump foil 20). In this thrust bearing 3A (3), slippage (friction) occurs between the top foil piece 11 and the damping foil piece 51, and between the damping foil piece 51 and the bump foil piece 21. Each slip (friction) occurs. Therefore, by increasing the number of sites that generate frictional damping, a higher frictional damping effect can be achieved compared to the conventional case, and vibration and impact can be absorbed well in the thrust direction of the rotating shaft 1.

  In addition, since the bump foil piece 21 and the damping foil piece 51 are both divided in the radial direction so that the deformation in the radial direction of the top foil piece 11 is smooth, the top foil piece 11 is locally applied to the thrust collar 4. It is possible to suppress contact, thereby preventing local wear of the top foil piece 11 and preventing a reduction in bearing life and seizure.

  Further, since the bump foil piece 21b and the damping foil piece 51b are integrated by continuous sides, respectively, the bump foil piece 21 (back foil piece 21) and the damping foil piece 51 are formed. The damping foil piece 51 can be easily fixed to the base plate 30 by spot welding or the like.

  In addition, since the second slits 51c between the damping foil split pieces 51b are formed so as to overlap the first slits 21c between the bump foil split pieces 21b, each of the damping foil split pieces 51b is provided with a corresponding bump. It is possible to better follow the individual movements of the foil split piece 21b.

  Further, the end of the damping foil piece 51 on the upstream side in the rotation direction of the rotary shaft 1 is a fixed side 51a, and this fixed side 51a is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11, so that the top Without changing the shape of the foil piece 11 from the conventional one, it can be formed in the same manner as the conventional one, and thus the increase in cost can be suppressed. That is, when the fixed side 12 of the top foil piece 11 is directly attached to the base plate 30 without inserting the fixed side 51 a of the damping foil piece 51 under the fixed side 12 of the top foil piece 11, The height must be increased by the thickness of the damping foil piece 51 as compared with the prior art. However, by fixing the fixed side 12 of the top foil piece 11 on the fixed side 51a of the damping foil piece 51, such a design change can be made unnecessary, and a mold or the like needs to be newly manufactured. Disappears.

  In addition, since the fixed side 51a of the damping foil piece 51 is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11, the number of fixed points of the foil piece by spot welding (dot welding) or the like is controlled. It can be made the same as the conventional one not using the foil piece 51, and therefore, an increase in manufacturing cost can be suppressed.

Further, when the damping foil piece 51 is formed of a damping alloy, in addition to frictional damping due to slip between the foils, a damping effect due to deformation (bending deformation) of the damping foil piece 51 is also added. A high friction damping effect can be obtained.
Moreover, since the thin-walled portion 14 is formed in the vicinity of the top foil piece 11 on the downstream side in the rotational direction with respect to the fixed side 12, the downstream side in the rotational direction can be inclined more easily and smoothly when a load is applied. Therefore, the starting torque is reduced. In addition, even after the rotation shaft 1 starts to rotate, the top foil piece 11 can be easily and smoothly inclined, so that an optimum inclination angle can be easily obtained and the load capacity is improved.

Next, 2nd Embodiment of the thrust bearing 3 of this invention is described with reference to FIG. 5, FIG. 6 (a)-(d). 5 is a plan view of the thrust bearing, FIG. 6A is a cross-sectional view taken along the line BB in FIG. 5, FIG. 6B is a plan view of the damping foil piece, and FIG. 6C is a bump. FIG. 6D is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shapes of the damping foil piece and the bump foil piece.
The thrust bearing 3B (3) of the second embodiment is mainly different from the thrust bearing 3A (3) of the first embodiment, as shown in FIGS. 6 (a) to 6 (d). The end of the damping foil piece 55 on the downstream side in the rotation direction of the rotary shaft 1 is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11 as a fixed side 55a.

  That is, in the damping foil piece 55 of the present embodiment, as shown in FIG. 6B, the upstream side in the rotational direction of the rotary shaft 1 is equally divided into four (plural) in the radial direction, and the other side (rotation) The fixed side 55a that is the downstream side in the direction is a continuous side that is continuous in the radial direction. In this way, the side opposite to the fixed side 55a is divided into four parts, so that the damping foil piece 55 is constituted by four strip-shaped damping foil divided pieces 55b and a fixed side 55a (continuous side). .

  A second slit 55c is formed between each of the four strip-shaped damping foil divided pieces 55b. In the present embodiment, the second slits 55c are formed in an arc shape that forms a part of a circle concentric with the circle formed by the outer periphery of the damping foil piece 55. And these 2nd slits 55c are formed and arranged so that it may overlap with the 1st slit 21c of the bump foil piece 21, as shown in FIG.6 (d).

  Further, the damping foil piece 55 is formed longer on the downstream side in the rotational direction than the damping foil piece 51 of the first embodiment shown in FIGS. 3 and 4A to 4D, and its end side. That is, the fixed side 55a is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11 adjacent to the downstream side in the rotation direction as shown in FIGS. On the other hand, the upstream side in the rotation direction is a free end that is supported on the peak portion 23 of the bump foil piece 21 without being fixed in the present embodiment.

  Even in the thrust bearing 3B (3) having such a damping foil piece 55, the damping foil piece 55 is disposed between the bump foil piece (back foil piece) 21 and the top foil piece 11, respectively. When the rotary shaft 1 is subjected to vibration or impact in the axial direction (thrust direction) and the top foil piece 11 is pushed into the thrust collar 4 through the fluid lubricating film, a higher friction damping effect than in the prior art is obtained. As a result, vibration and impact can be absorbed well in the thrust direction of the rotating shaft 1.

  Further, since the bump foil piece 21 and the damping foil piece 55 are both divided in the radial direction so that the deformation in the radial direction of the top foil piece 11 is smooth, the top foil piece 11 is locally applied to the thrust collar 4. It is possible to suppress contact, thereby preventing local wear of the top foil piece 11 and preventing a reduction in bearing life and seizure.

  Further, the end of the damping foil piece 55 on the downstream side in the rotation direction of the rotating shaft 1 is defined as a fixed side 55a, and the fixed side 55a is attached to the base plate 30 together with the fixed side 12 of the top foil piece 11 adjacent to the downstream side in the rotation direction. Since it is fixed, the top foil piece 11 can be formed in the same manner as the conventional one without changing the shape of the top foil piece 11 from the conventional one as in the first embodiment, and the increase in cost can be suppressed.

Since the fixed side 55a of the damping foil piece 55 is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11, the number of fixed points of the foil piece by spot welding (dot welding) or the like is controlled. It can be made the same as the conventional one that does not use the foil piece 55, and therefore, an increase in manufacturing cost can be suppressed.
Furthermore, since the fixed side 55a of the damping foil piece 55 is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11 adjacent to the downstream side in the rotation direction, the top foil piece 11 is thrust collar through the fluid lubricating film. 4, when the top foil piece 11 and the damping foil piece 55 stacked one above the other are slid in a direction in which their free ends face each other, that is, in opposite directions (directions of fixed sides of each other). . Therefore, since the relative slip amount between the top foil piece 11 and the damping foil piece 55 is increased, a higher friction damping effect can be obtained.

Next, 3rd Embodiment of the thrust bearing 3 of this invention is described with reference to Fig.7 (a)-(c). 7A is a plan view of the thrust bearing, FIG. 7B is a cross-sectional view taken along the line CC of FIG. 7A, and FIG. 7C is a view of the damping foil piece and the bump foil piece. It is explanatory drawing which matched the top view and the side view in order to demonstrate a shape.
The thrust bearing 3C (3) of the third embodiment is mainly different from the thrust bearing 3A (3) of the first embodiment as shown in FIGS. 7 (a) to 7 (c). This is the point that the inclined surface 32 is formed on 31 and the height of the peak portion 23 of the bump foil piece 21 are all made the same.

  In the present embodiment, as shown in FIG. 7A, the entire region of the support region 31 that supports the bump foil piece 21, the damping foil piece 51, and the top foil piece 11 is the fixed side 12 of the top foil piece 11. The inclined surface 32 has a height that increases from the side toward the end side on the downstream side. That is, the inclined surface 32 is formed so as to be inclined in a direction orthogonal to the fixed side 21a of the bump foil piece 21 as shown in FIG.

  Further, the bump foil pieces 21 are formed in a corrugated plate shape in which trough portions 22 in contact with the base plate 30 and crest portions 23 in contact with the top foil pieces 11 are alternately arranged as in the first embodiment. . However, in the present embodiment, as shown in FIGS. 7B and 7C, the height of the peak portion 23 is all the same in the circumferential direction of the base plate 30. When the crests 23 of the two bump foil divided pieces 21b located on the outer peripheral side are compared with the crests 23 on the same row, the two bump foils whose tops are located on the inner circumference side are compared. The point which forms so that it may become a little higher than the peak part 23 of the division | segmentation piece 21b is the same as that of 1st Embodiment.

  Moreover, about the trough part 22 and the peak part 23, it arranges in the direction orthogonal to the fixed side 21a of the bump foil piece 21 similarly to the said embodiment. As a result, the peak portion 23 of the bump foil piece 21 has a predetermined height along the inclination direction of the inclined surface 32 of the base plate 30, that is, toward the downstream side in the rotation direction of the rotary shaft 1. It is getting higher. That is, it is the same as the first embodiment. Accordingly, the top foil piece 11 disposed on the bump foil piece 21 is formed in the same manner as the first embodiment in the inclination angle θ. In the present embodiment, the inclination angle θ is determined by the inclination angle θ of the inclined surface 32 as shown in FIG.

  Even in the thrust bearing 3C (3) of the present embodiment, the damping foil piece 51 is disposed between the bump foil piece (back foil piece) 21 and the top foil piece 11, respectively. When the top foil piece 11 is pushed into the thrust collar 4 through the fluid lubrication film due to vibration or impact in the direction (thrust direction), a higher friction damping effect is exhibited than in the prior art, and rotation Vibrations and shocks can be satisfactorily absorbed in the thrust direction of the shaft 1.

  In addition, since the bump foil piece 21 and the damping foil piece 51 are both divided in the radial direction so that the deformation in the radial direction of the top foil piece 11 is smooth, the top foil piece 11 is locally applied to the thrust collar 4. It is possible to suppress contact, thereby preventing local wear of the top foil piece 11 and preventing a reduction in bearing life and seizure.

  In addition, an inclined surface 32 is formed in each support region 31 of the base plate 30 so that the heights of the crests 23 of the bump foil pieces 21 are all the same, and the arrangement direction of the crests 23 is set to the inclination direction of the inclined surface 32. Since the top foil piece 11 is disposed on the inclined surface 32 via the back foil piece 21 and the damping foil piece 51, the height of the top foil piece 11 is adjusted along the inclined surface 32. It can be changed with high accuracy. That is, a predetermined inclination angle θ can be given to the top foil piece 11. Further, at this time, the bump foil piece 21 may be produced at a constant height without changing the height of the crest 23 in the circumferential direction, and therefore the processing cost can be suppressed. Therefore, according to this thrust bearing 3C (3), it is possible to facilitate processing, improve mass productivity, and reduce costs. Further, since machining becomes easy and variation is reduced, it is easy to obtain bearing performance (for example, bearing load capability) predicted at the time of design.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.
For example, in the above-described embodiment, the back foil 20, the damping foil 50, and the top foil 10 are each composed of six back foil pieces 21 (bump foil pieces 21), damping foil pieces 51 (damping foil pieces 55), and top foil pieces 11. Accordingly, six support regions 31 of the base plate 30 are formed (set) in accordance with this, but the back foil piece 21 (bump foil piece 21), the damping foil piece 51 (damping foil piece 55), the top As long as there are a plurality of foil pieces 11, the number of foil pieces 11 may be 5 or less, or 7 or more. In this case, the number of support regions 31 is naturally adjusted to the number of the back foil pieces 21 (bump foil pieces 21), the damping foil pieces 51 (damping foil pieces 55), and the top foil pieces 11.

  In the above-described embodiment, the damping foil piece 51 (damping foil piece 55) is arranged between the back foil piece 21 (bump foil piece 21) and the top foil piece 11, but the damping foil piece 51 (damping foil piece 55 (damping foil piece 55)). The vibrating foil piece 55) may be arranged in a plurality of layers (for example, two layers or three layers) in an overlapping manner. By arranging the damping foil pieces 51 (damping foil pieces 55) in a stacked manner in this way, friction damping due to slippage between the damping foil pieces 51 (damping foil pieces 55) is added, and therefore higher. A friction damping effect can be obtained.

  Moreover, in 3rd Embodiment, although the inclined surface 32 was formed in the support area | region 31 of the baseplate 30 with respect to 1st Embodiment, and the height of the peak part 23 of the bump foil piece 21 was made the same, other implementations As a form, the inclined surface 32 may be formed in the support region 31 of the base plate 30 with respect to the second embodiment, and the heights of the crests 23 of the bump foil pieces 21 may all be the same.

  Moreover, in the said embodiment, the bump foil piece 21 (back foil piece 21) and the damping foil piece 51 (damping foil piece 55) are divided into four bump foil division pieces 21b and the damping foil division piece 51b (damping foil division). Although formed by the piece 55b) and the continuous side (fixed side), each divided piece is not limited to four, and may be divided into any number as long as it is two or more. Further, it may be formed in a completely independent form without forming continuous sides, and thus without connecting the divided pieces.

  Moreover, in the said embodiment, the 1st slit 21c formed by dividing | segmenting the bump foil piece 21 (back foil piece 21) and the damping foil piece 51 (damping foil piece 55) into multiple in radial direction, the 1st Although the two slits 51c (second slit 55c) are formed in an arc shape, these slits may be formed in a linear shape, for example.

Moreover, in the said embodiment, the fixed side 51a (fixed side 55a) of the damping foil piece 51 (damping foil piece 55) and the fixed side 12 of the top foil piece 11 are piled up and down, and the base plate 30 is jointed by spot welding or the like. However, these fixed sides may be fixed to the base plate 30 separately in a state where they are shifted from each other without overlapping.
In addition to the above embodiments, various forms such as the shape of the top foil piece, the damping foil piece, the bump foil piece, the arrangement of the top foil piece and the bump foil piece on the support area, and the inclination direction of the inclined surface are adopted. Is possible.

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 3, 3A, 3B, 3C ... Thrust bearing, 4 ... Thrust collar, 10 ... Top foil, 11 ... Top foil piece, 12 ... Fixed side, 20 ... Back foil (bump foil), 21 ... Back foil Piece (bump foil piece), 21a ... Fixed side (end side), 21b ... Back foil piece (bump foil piece), 21c ... First slit, 22 ... Valley, 23 ... Mountain, 30 ... Base plate, 31 DESCRIPTION OF SYMBOLS ... Support area, 32 ... Inclined surface, 50 ... Damping foil, 51 ... Damping foil piece, 51a ... Fixed side, 51b ... Damping foil split piece, 51c ... Second slit, 55 ... Damping foil piece, 55a ... Fixed side, 55b ... Damping foil divided piece, 55c ... Second slit

Claims (6)

A thrust bearing disposed opposite to a thrust collar provided on a rotating shaft,
A top foil disposed opposite the thrust collar;
A back foil disposed on the surface of the top foil opposite to the surface facing the thrust collar;
An annular plate-like base plate that is disposed on the side of the back foil opposite to the top foil and supports the back foil;
The back foil is formed by a plurality of back foil pieces arranged in the circumferential direction of the base plate,
The top foil is formed by a plurality of top foil pieces respectively disposed on the back foil pieces,
Between the back foil piece and the top foil piece, a damping foil piece is arranged,
The back foil piece is divided into a plurality in the radial direction on at least one side in the circumferential direction,
The thrust bearing piece is characterized in that at least one side in the circumferential direction of the damping foil piece is divided into a plurality of parts in the radial direction. The back foil piece is divided into a plurality of pieces in the radial direction on one side in the circumferential direction, and the other side is a continuous side continuous in the radial direction.
2. The vibration damping foil piece according to claim 1, wherein one side of the circumferential direction is divided into a plurality of parts in the radial direction, and the other side is a continuous side continuous in the radial direction. Thrust bearing. In the back foil piece, a first slit is formed between a plurality of back foil divided pieces divided in the radial direction,
3. The thrust according to claim 2, wherein the damping foil piece includes a second slit that overlaps the first slit between a plurality of damping foil divided pieces that are divided in a radial direction. bearing. The top foil piece has a top foil fixed side that is fixed to the base plate at the end on the upstream side in the rotation direction of the rotating shaft,
In the damping foil piece, the end side on the upstream side in the rotation direction of the rotation shaft or the end side on the downstream side in the rotation direction is the continuous side, and the continuous side is together with the top foil fixed side of the top foil piece. The thrust bearing according to claim 2, wherein the thrust bearing is fixed to the base plate.   The vibration-damping foil piece has an end on the downstream side in the rotation direction of the rotating shaft as the continuous side, and the continuous side is fixed to the base plate together with the top foil fixing side of the top foil piece. The thrust bearing according to claim 4.   The thrust bearing according to any one of claims 1 to 5, wherein the damping foil piece is made of a damping alloy.

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