JP2016080119A - 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 resisting a high load.SOLUTION: A thrust bearing disposed to face a thrust collar provided on a rotary shaft comprises: a top foil formed by top foil pieces 11; and a back foil formed by back foil pieces 21 arranged in the circumferential direction of a base plate 30. At least one circumferential side of each back foil piece 21 is radially divided into a plurality of sections. A shim piece 51 which does not face at least a lowest bottom section of each back foil piece in an inner circumferential region of the back foil piece but faces at least an intermediate region in the radial direction of the back foil piece is provided between each back foil piece 21 and the base plate 30.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 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 when the load is high. Therefore, contact with the thrust collar is likely to occur on the downstream end side. When contact occurs, 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. In the bump foil divided in this way, (a) a bump foil having low rigidity is arranged on the inner peripheral side, or (b) the height of the bump foil peak on the inner peripheral side is reduced, so that the top foil is reduced. It is considered that the supporting force on the inner peripheral side is weakened to suppress the rising on the inner peripheral end side.

  However, even when trying to manufacture a thrust bearing by dividing and adjusting the bump foil in this way, for example, in (a), it is difficult to appropriately control the rigidity on the inner and outer peripheral sides of the bump foil, Therefore, it is difficult to design the bump foil. Further, in (b), since it is necessary to control the height of the bump foil crest at a level of 10 μm, it is difficult to manufacture, and it is particularly difficult to ensure quality during mass production.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a thrust bearing capable of withstanding a high load by suppressing the top foil piece from contacting the thrust collar. is there.

  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. The back foil piece is divided into a plurality of parts in the radial direction on at least one side in the circumferential direction. Between the back foil piece and the base plate, it faces at least the intermediate region in the radial direction of the back foil piece without facing at least the bottommost portion of the back foil piece in the inner peripheral region of the back foil piece. A shim piece is provided.

  According to this thrust bearing, at least the intermediate region in the radial direction of the back foil piece between the back foil piece and the base plate without facing at least the bottommost portion of the back foil piece in the inner peripheral side region of the back foil piece. Since the shim piece facing is arranged, the outer peripheral end side of the top foil piece is pushed into the back foil piece side to move away from the thrust collar, and the inner peripheral end side tries to get up to the thrust collar side. On the inner peripheral end side, a gap is generated between the top foil piece and the back foil piece by the shim piece, and a force to push the inner peripheral end side of the top foil piece back to the thrust collar side is generated until the gap is eliminated. The top foil piece does not rise on the inner peripheral end side. Therefore, the film thickness of the fluid lubricating film on the inner peripheral end side is prevented from becoming extremely thin on the downstream side edge side of the top foil.

  In this thrust bearing, it is preferable that the shim piece is formed so as not to face at least the bottommost part of the back foil piece in the outer peripheral side region of the back foil piece.

In general, in a thrust bearing, the pressure of the fluid lubrication film at the outer peripheral end of the top foil piece is the same as the ambient pressure (for example, atmospheric pressure). It is lower than where it entered the circumference. Accordingly, the outer peripheral end of the top foil piece is likely to rise to the thrust collar side, similarly to the inner peripheral end side.
Therefore, by forming a shim piece in the outer peripheral side region of the back foil piece so as not to face at least the bottommost part of the back foil piece, even if the outer peripheral end of the top foil piece tries to rise to the thrust collar side, Since there is a gap between the top foil piece and the back foil piece by the shim piece on the side, there is no force to push the outer peripheral edge of the top foil piece back to the thrust collar side until this gap disappears. The rise of the outer peripheral edge of the does not occur. Therefore, it is possible to prevent the thickness of the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece.

  In another thrust bearing according to the present invention, the thrust bearing is disposed to face a thrust collar provided on a rotating shaft, the top foil being disposed to face the thrust collar, and the top foil, A back foil disposed on a surface opposite to the surface facing the thrust collar, and an annular plate-shaped base plate disposed on a side of the back foil opposite to the top foil to support the back foil. The back foil is formed by a plurality of back foil pieces arranged in the 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. The back foil piece is divided into a plurality of parts in the radial direction on at least one side in the circumferential direction. Between the top foil piece and the back foil piece, at least in the radial direction of the back foil piece without facing at least the topmost part of the back foil piece in the inner peripheral side region of the back foil piece A shim piece facing the region is provided.

  According to this thrust bearing, between the top foil piece and the back foil piece, at least in the radial direction of the back foil piece without facing at least the topmost part of the back foil piece in the inner peripheral region of the back foil piece. Since the shim piece facing the intermediate region is arranged, the outer peripheral end side of the top foil piece is pushed into the back foil piece side to move away from the thrust collar, and the inner peripheral end side tries to rise to the thrust collar side. However, since a gap is formed between the top foil piece and the back foil piece by the shim piece on the inner peripheral end side, the force that pushes back the inner peripheral end side of the top foil piece to the thrust collar side until the gap disappears. Does not occur, and the top foil piece does not rise on the inner peripheral end side. Therefore, the film thickness of the fluid lubricating film on the inner peripheral end side is prevented from becoming extremely thin on the downstream end side of the top foil piece.

  In this thrust bearing, it is preferable that the shim piece is formed so as not to face at least the topmost part of the back foil piece in the outer peripheral side region of the back foil piece.

As described above, since the pressure of the fluid lubricating film is the same as the ambient pressure at the outer peripheral end of the top foil piece, the outer peripheral end is easily raised to the thrust collar side in the same manner as the inner peripheral end side.
Therefore, in the outer peripheral side region of the back foil piece, by forming a shim piece so as not to face at least the topmost part of the back foil piece, even if the outer peripheral end of the top foil piece rises to the thrust collar side, the outer peripheral end Since there is a gap between the top foil piece and the back foil piece by the shim piece on the side, there is no force to push the outer peripheral edge of the top foil piece back to the thrust collar side until this gap disappears. The rise of the outer peripheral edge of the does not occur. Therefore, it is possible to prevent the thickness of the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece.

In the thrust bearing, it is preferable that one side of the back foil piece is divided into a plurality of parts in the radial direction and the other side is a continuous side continuous in the radial direction.
According to this thrust bearing, one side in the circumferential direction of the back foil piece is divided into a plurality of pieces in the radial direction, so that the divided piece on the inner peripheral side and the divided piece on the outer peripheral side are independent from each other. Accordingly, the deformation of the back foil piece that occurs when the top foil piece is pushed into the back foil piece side becomes smooth in the radial direction. Therefore, the supporting force by the back foil piece also changes more smoothly from the inner peripheral side toward the outer peripheral side. In addition, since the divided pieces of the back foil piece are integrated by the continuous sides, the back foil piece can be easily fixed on the base plate.

Further, in the thrust bearing, the shim piece is integrally formed with a shim fixing side fixed to the base plate on one side in the circumferential direction, and the shim fixing side is the back foil piece or the top piece. The foil piece is preferably formed to have the same length as the length in the radial direction.
According to this thrust bearing, the shim fixing side is formed to have the same length as the length of the back foil piece or the top foil piece in the radial direction. Therefore, the shim fixing side is fixed to the back foil piece fixing side or the top foil piece at the time of manufacture. It can be easily fixed to the base plate by spot welding or the like.

  According to the thrust bearing of the present invention, between the back foil piece and the base plate, or between the top foil piece and the back foil piece, in the inner peripheral side region of the back foil piece, the bottom or top part of the back foil piece. Since the shim piece opposed to at least the intermediate region in the radial direction of the back foil piece is disposed without facing, the difference in film thickness of the fluid lubricating film between the inner and outer circumferences can be reduced by the shim piece, Accordingly, it is possible to prevent the thickness of the fluid lubricating film on the inner peripheral end side from becoming extremely thin. Therefore, it is possible to prevent the top foil piece from coming into contact with the thrust collar on the inner peripheral end side, and to be excellent in withstanding a high load.

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 which looked at the principal part 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 arrow sectional drawing of FIG. 3, (b) is a top view of a bump foil piece, (c) is shim. 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 shape of the bump foil piece and the shim. It is a figure which shows 2nd Embodiment of the thrust bearing which concerns on this invention, (a) is a top view of a thrust bearing, (b) is BB sectional view taken on the line of (a), (c) is bump foil. It is explanatory drawing which matched the top view and side view in order to demonstrate the shape of a piece and a shim. It is a top view of a 3rd embodiment of a thrust bearing concerning the present invention. It is a figure which shows 3rd Embodiment of the thrust bearing which concerns on this invention, (a) is CC sectional view taken on the line of FIG. 6, (b) is a top view of a bump foil piece, (c) is shim. 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 shape of the bump foil piece and the shim. It is a top view of 4th Embodiment of the thrust bearing which concerns on this invention. It is a figure which shows 4th Embodiment of the thrust bearing which concerns on this invention, (a) is DD sectional view taken on the line of FIG. 8, (b) is a top view of a bump foil piece, (c) is shim. 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 shape of the bump foil piece and the shim. It is a top view of 5th Embodiment of the thrust bearing which concerns on this invention. It is a figure which shows 5th Embodiment of the thrust bearing which concerns on this invention, (a) is EE arrow sectional drawing of FIG. 10, (b) is a top view of a bump foil piece, (c) is shim. 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 shape of the bump foil piece and the shim. It is a top view of the shim in the modification of 5th Embodiment. It is a top view of 6th Embodiment of the thrust bearing which concerns on this invention. It is a figure which shows 6th Embodiment of the thrust bearing which concerns on this invention, (a) is FF sectional view taken on the line of FIG. 13, (b) is a top view of a bump foil piece, (c) is shim. 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 shape of the bump foil piece and the shim. It is a figure which shows 7th Embodiment of the thrust bearing which concerns on this invention, (a) is sectional drawing corresponding to the AA arrow sectional drawing of FIG. 3, (b) is a top view of a bump foil piece, (c) is a plan view of the shim, and (d) is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. It is a figure which shows 9th Embodiment of the thrust bearing which concerns on this invention, (a) is sectional drawing corresponding to CC sectional view taken on the line of FIG. 6, (b) is a top view of a bump foil piece, (c) is a plan view of the shim, and (d) is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. It is a figure which shows 10th Embodiment of the thrust bearing which concerns on this invention, (a) is sectional drawing corresponding to DD sectional view taken on the line of FIG. 8, (b) is a top view of a bump foil piece, (c) is a plan view of the shim, and (d) is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. It is a figure which shows 11th Embodiment of the thrust bearing which concerns on this invention, (a) is sectional drawing corresponding to the EE arrow sectional drawing of FIG. 10, (b) is a top view of bump foil piece, (c) is a plan view of the shim, and (d) is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. It is a figure which shows 12th Embodiment of the thrust bearing which concerns on this invention, (a) is sectional drawing corresponding to FF arrow directional cross-sectional view of FIG. 13, (b) is a top view of bump foil piece, (c) is a plan view of the shim, and (d) is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim.

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.

“First Embodiment”
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. It is the side view of the thrust bearing 3 which looked at the principal part of the state in a cross section. 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 bump foil piece, and FIG. 4C is a shim. 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 shape of the bump foil piece and the shim.

  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 plurality of shims 50 are provided between the back foil 20 and the base plate 30. Configured.

  In the present 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 3A, and the base plate 30 is connected via the bearing spacer 40 by the fastening bolts 41. ing. 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 shim 50, the back foil 20, 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 and the top foil 10 are both formed by a plurality (six) of the back foil pieces 21 and the top foil pieces 11, and therefore the base plate 30 has a circumferential direction. Six support regions 31 are formed by dividing into six (equally divided into six). Six shims 50 are also provided corresponding to these 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 shim 50, the back foil piece 21, and the top foil piece 11 are arranged and supported in the respective support regions 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 slightly smaller than the top foil pieces 11 to be described later. Therefore, the back foil pieces 21 are not exposed to the thrust collar 4 side on the base plate 30 as shown in FIG. It has been broken.

  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, 4B, 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 21 (back foil piece) is a foil (metal thin plate) having a thickness of about several hundreds μm formed into a corrugated plate by press molding, and the whole is fan-shaped as shown in FIG. Is formed in a substantially trapezoidal shape with the inner peripheral side and the outer peripheral side each having an arc shape.

  As shown in FIG. 4D, the bump foil piece 21 formed in the corrugated plate shape has a valley portion 22 that contacts the base plate 30 via the shim 50 and a peak portion 23 that contacts the top foil piece 11. They are arranged alternately. The trough 22 forms the bottom of the bump foil piece 21 (back foil piece 21), and the top (ridge line) of the peak 23 forms the top of the bump foil piece 21 (back foil piece 21). ing. Here, in the bump foil piece 21, the end side 21 a on the downstream side in the rotation direction of the rotating shaft 1 shown in FIG. 3 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 21 a (end side) of the bump foil piece 21. 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. As it goes, it is formed to increase by a predetermined height as shown in FIGS. 4 (a) and 4 (d).

  Further, as shown in FIG. 4B, the bump foil piece 21 has a radial direction on one side in the circumferential direction, in this embodiment, on the opposite side to the end side 21a on the downstream side in the rotational direction of the rotary shaft 1. The end side 21a (fixed side) which is equally divided into four (plurality) and is on the other side is a continuous side 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.

  Between the four strip-shaped bump foil division pieces 21b, slits 21c are respectively formed. In the present embodiment, these 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 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-like bump foil divided pieces 21b by the slit 21c having such a width, the four strip-like bump foil divided pieces 21b move independently. It has become.

  In the present embodiment, the bump foil piece 21 is formed to have substantially uniform rigidity between the four bump foil divided pieces 21b without changing the rigidity particularly between the inner peripheral side and the outer peripheral side. . Moreover, the height of the top part of the peak part 23 on the same row | line | column is also formed substantially the same. Thereby, design and manufacture of the bump foil piece 21 are facilitated.

  Further, the bump foil piece 21 is arranged at a position where the fixed side 21a substantially overlaps with the shim 50 and the end side on the downstream side in the rotation direction of the rotary shaft 1 of the top foil piece 11 in plan view. . Then, along the forming direction of the valley portion 22 that becomes the end side 21a, the base plate 30 is spot-welded (spot welded) together with a shim 50 described later, and fixed.

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 and the shim 50 can be fixed to the base plate 30 by, for example, screwing in addition to spot welding.

  As described above, six shims 50 are provided in the circumferential direction of the base plate 30 corresponding to the six support regions 31 shown in FIG. 3, and bump foils are provided as shown in FIGS. The shim piece 51 formed and arranged to face the outer peripheral side without facing the inner peripheral side of the piece 21, and one side of the shim piece 51 in the circumferential direction, in this embodiment, the rotational direction of the rotary shaft 1 And a shim fixing side 52 integrally formed on the downstream side.

  The shim piece 51 is formed in a substantially trapezoidal shape in which a sector-shaped apex side is cut out and an inner peripheral side and an outer peripheral side are arc-shaped. In the present embodiment, a portion facing the two bump foil divided pieces 21b on the inner peripheral side of the bump foil piece 21 is cut out, and the two bump foil divided pieces 21b on the outer peripheral side are not opposed to this. Oppositely, it is arrange | positioned in contact with the lowest part, ie, the trough part 22, and.

  In the present embodiment, the shim fixed side 52 is formed to have the same length as the radial length of the bump foil piece 21, and therefore, the shim fixed side 52 is formed to have the same length as the fixed side 21 a (end side) of the bump foil piece 21. , Is placed on top of this. Thereby, as described above, the shim fixing side 52 is spot-welded (dot welding) to the base plate 30 together with the fixing side 21a of the bump foil piece 21 and fixed.

  These shims 50 are formed of a thin plate (foil) made of metal or alloy having a thickness of about several tens of μm. Specifically, it is formed of a metal such as stainless steel, aluminum, or copper, or various damping alloys. By arranging the shim 50 having such a thickness, the shim piece 51 supports the bump foil piece 21 on the inner peripheral side relatively by lifting and supporting only the outer peripheral side of the bump foil piece 21 by the thickness. The spring reaction force of can be weakened. Therefore, the difference in film thickness between the inner and outer circumferences of the fluid lubricating film formed between the thrust collar 4 and the top foil 10 can be sufficiently reduced.

  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 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. Therefore, the top foil piece 11 is pushed almost equally into the bump foil piece 21 on both the outer peripheral side and the inner peripheral side, and the film thickness of the fluid lubricating film on the inner peripheral end side is prevented from becoming extremely thin. .

  As shown in FIG. 4C, the shim piece 51 of the shim 50 does not completely cut out the inner peripheral side, and at least the bump foil piece 21 in the inner peripheral side region of the bump foil piece 21. If it is made not to oppose the trough part 22 which becomes the lowest part of this, you may leave the part in the inner peripheral side area | region of the bump foil piece 21. FIG. Specifically, a portion facing the peak 23 excluding the valley 22 may be left in a comb shape. Even if a portion facing the peak portion 23 is left in this way, this portion is not in direct contact with the bump foil piece 21 and is opposed to the peak portion 23 with a gap, so that the shim piece is shown in FIG. As with the shim piece 51 shown in FIG. 5, only the outer peripheral side of the bump foil piece 21 is lifted by the thickness, and thus functions similarly to the shim piece 51.

  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 a shape that is almost the same as the bump foil piece 21 and slightly longer in the circumferential direction. 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 bump foil pieces 21 and are arranged at equal intervals in the circumferential direction of the base plate 30 so as to be substantially annular as a whole. The top foil 10 is formed by arrange | positioning at plate shape.

  The top foil piece 11 is formed slightly smaller than the support region 31 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 so as to cover the upper surfaces thereof without interfering with each other and without exposing the bump foil pieces 21 and the shims 50 to the thrust collar 4 side. . 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 bump foil piece 21 or may be formed smaller than the bump foil piece 21.

  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, as shown in FIG. 4A, the fixed side 12 is disposed apart from the bump foil piece 21 and the shim 50 and is fixed to the base plate 30 by spot welding (dot welding).

  Further, the top foil piece 11 is bent at the downstream side in the rotation direction from the fixed side 12, so that the top foil piece 11 is raised so as to absorb a 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 end (trailing edge) side on the downstream side in the rotational direction is simply a free end supported on the peak portion 23 of the bump foil piece 21 without being fixed.

  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. Accordingly, the top foil piece 11 is placed on the bump foil piece 21 so that the top foil piece 11 moves from the fixed side 12 side toward the fixed side 21a side of the bump foil piece 21 along the arrangement direction of the peak portions 23. The bump foil pieces 21 are inclined at an initial inclination angle set by the crests 23 of the bump foil pieces 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 mountain parts 23 except for the thin part 14 (other parts) so as to be evenly supported by these parts. 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) by the pressure of the fluid lubricating film, and the thrust collar 4 comes out of contact with the top foil piece 11 and rotates without contact. To come.

  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, since the shim 50 is disposed between the bump foil piece 21 and the base plate 30, the bump foil piece 21 is lifted to the thrust collar 4 side (top foil piece 11 side) by the shim piece 51 on the outer peripheral end side. In contrast, the bump foil piece 21 is not lifted on the inner peripheral end side, and therefore a gap is formed between the top foil piece 11 and the bump foil piece 21. Therefore, until the gap is eliminated, the bump foil piece 21 does not have a force to push the inner peripheral end side of the top foil piece 11 back to the thrust collar 4 side, so that the inner peripheral end side of the top foil piece 11 does not rise.

  Further, even if the inner peripheral end side of the top foil piece 11 is pushed into the bump foil piece 21 side and the gap is eliminated, the spring reaction force by the bump foil piece 21 becomes weaker than the outer peripheral end side. Therefore, the inner peripheral end side of the top foil piece 11 is difficult to get up. Therefore, on the downstream side edge side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral edge side is prevented from becoming extremely thin.

  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 support force by the bump foil piece 21 (back foil piece) is also increased from the inner circumference side to the outer circumference. It changes more smoothly toward the side.

  In the thrust bearing 3 </ b> A (3) of the present embodiment, since the shim piece 51 (shim 50) is disposed between the bump foil piece 21 and the base plate 30, the inner peripheral end side of the top foil piece 11. Can be prevented from rising to the thrust collar 4 side, and therefore, on the downstream side edge side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral edge side can be prevented from becoming extremely thin. Can do. Therefore, the thrust bearing 3A (3) can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in withstanding a high load.

  In addition, the shim piece 51 is disposed without changing the height of the bump foil piece 21 between the inner peripheral end side and the outer peripheral end side, thereby preventing the top foil piece 11 from rising on the inner peripheral end side. Therefore, compared to the case where rising is prevented by changing the height of the bump foil piece 21, the difference in the supporting force between the inner and outer circumferences of the top foil piece 11 can be easily and accurately created. it can. Accordingly, the thrust bearing 3A (3) can be designed and manufactured more easily than when the height of the crest of the bump foil piece 21 is changed between the inner peripheral end side and the outer peripheral end side or the rigidity is changed. In addition, since the dimensional management becomes easy, it is effective for mass production, and the manufacturing cost can be reduced.

  Further, since one side in the circumferential direction of the bump foil piece 21 is divided into a plurality of pieces in the radial direction to form the bump foil divided piece 21b, the inner bump side piece 21b and the outer bump piece piece 21b are separated. Therefore, 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. Therefore, since the supporting force by the bump foil piece 21 also changes more smoothly from the inner circumference side to the outer circumference side, the top foil piece 11 can be prevented from contacting the thrust collar 4 locally. The local abrasion of the foil piece 11 can be prevented, and the bearing life can be reduced and seizure can be prevented. Further, since the bump foil divided piece 21b is integrated by the end side 21a (continuous side), the bump foil piece 21 can be easily fixed on the base plate 30.

  Further, since the shim fixing side 52 is formed to have the same length as the radial length of the bump foil piece 21, the shim fixing side 52 is overlapped with the fixing side (end side 21a) of the bump foil piece 21, and spot welding or the like. Thus, the base plate 30 can be fixed. Therefore, the manufacturing can be facilitated and the manufacturing cost can be reduced.

“Second Embodiment”
Next, 2nd Embodiment of the thrust bearing 3 of this invention is described with reference to Fig.5 (a)-(c). 5A is a plan view of the thrust bearing, FIG. 5B is a cross-sectional view taken along the line B-B in FIG. 5A, and FIG. 5C illustrates the shape of the bump foil piece and the shim. It is explanatory drawing which matched the top view and the side view in order to do. 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. 5 (a) to 5 (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. 5A, the entire region supporting the shim 50, the bump foil piece 21, and the top foil piece 11 in the support region 31 is viewed from the fixed side 12 side of the top foil piece 11. The inclined surface 32 increases in height as it goes toward the end side on the downstream side. That is, the inclined surface 32 is formed to be inclined in a direction orthogonal to the fixed side 21a of the bump foil piece 21 as shown in FIG.

  As for the bump foil pieces 21, similarly to the first embodiment, the corrugated plate shape in which the valley portions 22 that contact the base plate 30 via the shims 50 and the peak portions 23 that contact the top foil pieces 11 are alternately arranged. Is formed. However, in this embodiment, as shown in FIGS. 5B and 5C, the height of the crest portion 23 is all the same in the circumferential direction of the base plate 30. It is to be noted that the four bump foil divided pieces 21b are formed in substantially the same manner without changing the rigidity and without changing the height of the top portion of the peak portion 23, as in the first embodiment.

  Further, the valleys 22 and the peaks 23 are arranged in a direction orthogonal to the fixed side 21a of the bump foil piece 21 as in the first 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 3 </ b> B (3) of the present embodiment, the shim piece 51 (shim 50) is disposed between the bump foil piece 21 and the base plate 30, and therefore the inner peripheral end side of the top foil piece 11. Can be prevented from rising to the thrust collar 4 side, and therefore, on the downstream side edge side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral edge side can be prevented from becoming extremely thin. Can do. Therefore, this thrust bearing 3B (3) can also prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in being able to withstand a high load.

  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. Since the top foil piece 11 is disposed on the inclined surface 32 via the shim 50 and the back foil piece 21, the height of the top foil piece 11 can be accurately changed along the inclined surface 32. Can be made. 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 3B (3), processing can be facilitated, mass productivity can be improved, and cost can be reduced. 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.

“Third Embodiment”
Next, a third embodiment of the thrust bearing 3 of the present invention will be described with reference to FIGS. 6 and 7A to 7D. 6 is a plan view of the thrust bearing, FIG. 7A is a cross-sectional view taken along the line CC of FIG. 6, FIG. 7B is a plan view of the bump foil piece, and FIG. FIG. 7D is a plan view and FIG. 7D is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. The thrust bearing 3C (3) of the third embodiment is mainly different from the thrust bearing 3A (3) of the first embodiment in that the shim fixing side 52 of the shim 50 is located on the upstream side in the rotation direction of the rotary shaft 1. It is a point.

  That is, six shims 50 in the present embodiment are also provided in the circumferential direction of the base plate 30 corresponding to the six support regions 31 shown in FIG. 6, and as shown in FIGS. 7 (c) and 7 (d). The shim piece 51 formed and arranged so as to face the outer peripheral side without facing the inner peripheral side of the bump foil piece 21, and one side in the circumferential direction of the shim piece 51, in this embodiment, the rotating shaft 1 And a shim fixing side 52 integrally formed on the upstream side in the rotation direction.

  Similar to the shim piece 51 of the first embodiment, the shim piece 51 is formed in a substantially trapezoidal shape in which a fan-shaped apex side is cut out and an inner peripheral side and an outer peripheral side are arcuate. Also in the present embodiment, the portion facing the two bump foil divided pieces 21b on the inner peripheral side of the bump foil piece 21 is cut out, and the two bump foil divided pieces 21b on the outer peripheral side are not opposed to this. Oppositely, it is arrange | positioned in contact with the lowest part, ie, the trough part 22, and.

  As shown in FIG. 6, the shim fixing side 52 is formed to have the same length as that of the top foil piece 11 in the radial direction in the present embodiment. Therefore, the shim fixing side 52 is formed to have the same length as the fixed side 12 of the top foil piece 11. It is arranged to overlap this. Thereby, the shim fixed side 52 of this embodiment is spot-welded (dot welding) to the base plate 30 together with the fixed side 12 of the top foil piece 11 and fixed. The edge on the other side in the circumferential direction of the shim piece 51, that is, the edge on the downstream side in the rotation direction of the rotary shaft 1 is the end of the bump foil piece 21 as shown in FIGS. 7 (a) and 7 (d). It is located upstream of the side 21a (fixed side) in the rotational direction of the rotary shaft 1 and is a free end.

  Note that the shim piece 51 of the shim 50 of the present embodiment also includes at least the inner peripheral side region of the bump foil piece 21 without cutting out the inner peripheral side as shown in FIG. A part of the bump foil piece 21 may be left in the inner peripheral side area of the bump foil piece 21 as long as it does not face the valley 22 which is the bottom of the bump foil piece 21. Specifically, a portion facing the peak 23 excluding the valley 22 may be left in a comb shape.

  Even in the thrust bearing 3 </ b> C (3) of the present embodiment, the shim piece 51 (shim 50) is disposed between the bump foil piece 21 and the base plate 30, and therefore the inner peripheral end side of the top foil piece 11. Can be prevented from rising to the thrust collar 4 side, and therefore, on the downstream side edge side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral edge side can be prevented from becoming extremely thin. Can do. Therefore, the thrust bearing 3C (3) can also prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in being able to withstand a high load.

  In addition, the shim piece 51 is disposed without changing the height of the bump foil piece 21 between the inner peripheral end side and the outer peripheral end side, thereby preventing the top foil piece 11 from rising on the inner peripheral end side. Therefore, compared to the case where rising is prevented by changing the height of the bump foil piece 21, the difference in the supporting force between the inner and outer circumferences of the top foil piece 11 can be easily and accurately created. it can. Accordingly, the thrust bearing 3A (3) can be designed and manufactured more easily than when the height of the crest of the bump foil piece 21 is changed between the inner peripheral end side and the outer peripheral end side or the rigidity is changed. In addition, since the dimensional management becomes easy, it is effective for mass production, and the manufacturing cost can be reduced.

  Further, since the shim fixing side 52 is formed to have the same length as the radial length of the top foil piece 11, the shim fixing side 52 is overlapped with the fixing side 12 of the top foil piece 11 to the base plate 30 by spot welding or the like. Can be fixed. Therefore, the manufacturing can be facilitated and the manufacturing cost can be reduced.

As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same.
In this way, the inclined surface 32 is formed in each support region 31, 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 made to coincide with the inclination direction of the inclined surface 32. Then, the height of the top foil piece 11 can be accurately changed along the inclined surface 32 by disposing the top foil piece 11 on the inclined surface 32 via the shim 50 and the bump foil piece 21. it can. 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 the thrust bearing of this modified example, in addition to the effect of the third embodiment, it is possible to obtain an effect of facilitating the processing, improving the mass productivity, and reducing the cost. 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.

“Fourth Embodiment”
Next, 4th Embodiment of the thrust bearing 3 of this invention is described with reference to FIG. 8, FIG. 9 (a)-(d). 8 is a plan view of the thrust bearing, FIG. 9A is a cross-sectional view taken along the line DD in FIG. 8, FIG. 9B is a plan view of the bump foil piece, and FIG. FIG. 9D is a plan view, and FIG. 9D is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. The thrust bearing 3D (3) of the fourth embodiment is mainly different from the thrust bearing 3C (3) of the third embodiment, in that the shim 50 is formed by the top foil piece 11 and the bump foil piece 21 (back foil piece). It is the point arrange | positioned between.

  That is, six shims 50 in the present embodiment are also provided in the circumferential direction of the base plate 30 corresponding to the six support regions 31 shown in FIG. 8, and as shown in FIGS. 9 (c) and 9 (d). The shim piece 51 formed and arranged so as to face the outer peripheral side without facing the inner peripheral side of the bump foil piece 21, and one side in the circumferential direction of the shim piece 51, in this embodiment, the rotating shaft 1 And a shim fixing side 52 integrally formed on the upstream side in the rotation direction.

  Similar to the shim piece 51 of the third embodiment, the shim piece 51 is formed in a substantially trapezoidal shape in which a fan-shaped apex side is cut out and an inner peripheral side and an outer peripheral side are arcuate. Also in the present embodiment, the portion facing the two bump foil divided pieces 21b on the inner peripheral side of the bump foil piece 21 is cut out, and the two bump foil divided pieces 21b on the outer peripheral side are not opposed to this. Opposed to each other. However, since the shim piece 51 of the shim 50 of the present embodiment is disposed not on the lower side of the bump foil piece 21 (back foil piece) but on the upper side of the bump foil piece 21, the topmost portion of the bump foil piece 21 is provided. That is, it is arranged in contact with the ridgeline (top) of the mountain portion 23.

  As for the shim piece 51 of the shim 50, as shown in FIG. 9C, at least the bump foil piece 21 in the inner peripheral side region of the bump foil piece 21 without completely cutting out the inner peripheral side thereof. As long as it faces the top of the ridge 23 and does not come into contact therewith, a part thereof may be left in the inner peripheral region of the bump foil piece 21. Specifically, a portion facing the valley 22 excluding the peak 23 may be left in a comb shape. Even if a portion facing the valley portion 22 is left in this way, this portion does not directly contact the bump foil piece 21 and is opposed to the valley portion 22 with a gap, so that the shim piece is shown in FIG. In the same manner as the shim piece 51 shown in FIG. 5, a gap is formed on the inner peripheral side of the bump foil piece 21, and thus functions similarly to the shim piece 51.

  Similar to the third embodiment, the shim fixing side 52 is formed to have the same length as the length of the top foil piece 11 in the radial direction in the present embodiment, and thus the same length as the fixed side 12 of the top foil piece 11. And is arranged so as to overlap this. Thereby, the shim fixing side 52 of the present embodiment is also spot-welded (dot welding) to the base plate 30 together with the fixing side 12 of the top foil piece 11 and fixed.

  However, in this embodiment, since the shim 50 is disposed on the upper side of the bump foil piece 21, the shim fixing side 52 side of the shim 50 is the same as the fixing side 12 side of the top foil piece 11, the shim fixing side 52. The downstream side in the rotational direction is bent. In other words, the bump foil piece 21 is raised so as to absorb a step corresponding to the height of the peak portion 23 of the bump foil piece 21, and the downstream side in the rotation direction is placed on the peak portion 23 of the bump foil piece 21. The end side 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.

  In the thrust bearing 3D (3) of this embodiment, since the shim piece 51 (shim 50) is disposed between the top foil piece 11 and the bump foil piece 21, the outer peripheral end of the top foil piece 11 Even if the side is pushed into the bump foil piece 21 side and tries to move away from the thrust collar 4, and the inner peripheral end side tries to rise to the thrust collar 4 side, the shim piece 51 causes the top foil piece 11 and the bump on the inner peripheral end side. Since a gap is formed between the foil piece 21 and the gap, the force to push the inner peripheral end of the top foil piece 11 back to the thrust collar 4 is not generated until the gap disappears. Does not happen. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing 3D (3) can also prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in withstanding a high load.

  In addition, the shim piece 51 is disposed without changing the height of the bump foil piece 21 between the inner peripheral end side and the outer peripheral end side, thereby preventing the top foil piece 11 from rising on the inner peripheral end side. Therefore, compared to the case where rising is prevented by changing the height of the bump foil piece 21, the difference in the supporting force between the inner and outer circumferences of the top foil piece 11 can be easily and accurately created. it can. Therefore, the thrust bearing 3D (3) can be designed and manufactured more easily than when the height of the crest of the bump foil piece 21 is changed between the inner peripheral end side and the outer peripheral end side or the rigidity is changed. In addition, since the dimensional management becomes easy, it is effective for mass production, and the manufacturing cost can be reduced.

  Further, since the shim fixing side 52 is formed to have the same length as the radial length of the top foil piece 11, the shim fixing side 52 is overlapped with the fixing side 12 of the top foil piece 11 to the base plate 30 by spot welding or the like. Can be fixed. Therefore, the manufacturing can be facilitated and the manufacturing cost can be reduced.

As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same.
In this way, the inclined surface 32 is formed in each support region 31, 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 made to coincide with the inclination direction of the inclined surface 32. Then, by arranging the top foil piece 11 on the inclined surface 32 via the bump foil piece 21 and the shim 50, the height of the top foil piece 11 can be accurately changed along the inclined surface 32. it can. 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 the thrust bearing of this modified example, in addition to the effect of the fourth embodiment, it is possible to obtain an effect of facilitating the processing, improving the mass productivity, and reducing the cost. 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.

“Fifth Embodiment”
Next, 5th Embodiment of the thrust bearing 3 of this invention is described with reference to FIG. 10, FIG. 11 (a)-(d). 10 is a plan view of the thrust bearing, FIG. 11A is a cross-sectional view taken along line EE in FIG. 10, FIG. 11B is a plan view of the bump foil piece, and FIG. FIG. 11 (d) is a plan view and FIG. 11 (d) is an explanatory diagram that associates the plan view and the side view to explain the shape of the bump foil pieces and shims. The thrust bearing 3E (3) of the fifth embodiment is different from the thrust bearing 3D (3) of the fourth embodiment mainly in that the shim fixing side 52 of the shim 50 is located on the downstream side in the rotation direction of the rotary shaft 1. It is a point.

  That is, six shims 50 in the present embodiment are also provided in the circumferential direction of the base plate 30 corresponding to the six support regions 31 shown in FIG. 10, as shown in FIGS. 11 (c) and 11 (d). The shim piece 51 formed and arranged so as to face the outer peripheral side without facing the inner peripheral side of the bump foil piece 21, and one side in the circumferential direction of the shim piece 51, in this embodiment, the rotating shaft 1 The shim fixing side 52 is integrally formed on the downstream side in the rotation direction.

  Similar to the shim piece 51 of the fourth embodiment, the shim piece 51 is formed in a substantially trapezoidal shape in which a fan-shaped apex side is cut out and an inner peripheral side and an outer peripheral side are arcuate. Also in the present embodiment, the portion facing the two bump foil divided pieces 21b on the inner peripheral side of the bump foil piece 21 is cut out, and the two bump foil divided pieces 21b on the outer peripheral side are not opposed to this. Oppositely, it is arrange | positioned in contact with the ridgeline (top part) of the peak part, ie, the peak part 23, and.

  In this embodiment, the shim fixing side 52 is formed to have the same length as the length of the top foil piece 11 or the bump foil piece 21 in the radial direction. However, since it is formed on the downstream side in the rotation direction of the rotary shaft 1, it does not overlap with the fixed side 12 of the top foil piece 11 as shown in FIG. Without being overlapped with the (fixed side), it is spot welded (dot welding) to the base plate 30 on the outside of the end side 21a of the bump foil piece 21 (downstream in the rotation direction of the rotary shaft 1) and fixed. .

  Also in this embodiment, since the shim 50 is disposed on the upper side of the bump foil piece 21, the shim fixed side 52 side of the shim 50 is bent on the upstream side in the rotational direction from the shim fixed side 52. In other words, the bump foil piece 21 is raised so as to absorb a level difference corresponding to the height of the peak portion 23 of the bump foil piece 21, and the upstream side in the rotation direction is placed on the peak portion 23 of the bump foil piece 21. Further, the end side on the upstream side in the rotation direction is merely a free end supported on the peak portion 23 of the bump foil piece 21 without being fixed.

  Even in the thrust bearing 3E (3) of the present embodiment, since the shim piece 51 (shim 50) is disposed between the top foil piece 11 and the bump foil piece 21, the inner periphery of the top foil piece 11 It is possible to prevent the end side from rising to the thrust collar 4 side, and therefore, on the downstream end side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral end side is prevented from becoming extremely thin. can do. Therefore, this thrust bearing 3E (3) can also prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in being able to withstand a high load.

  In addition, the shim piece 51 is disposed without changing the height of the bump foil piece 21 between the inner peripheral end side and the outer peripheral end side, thereby preventing the top foil piece 11 from rising on the inner peripheral end side. Therefore, compared to the case where rising is prevented by changing the height of the bump foil piece 21, the difference in the supporting force between the inner and outer circumferences of the top foil piece 11 can be easily and accurately created. it can. Therefore, the thrust bearing 3E (3) can be easily designed and manufactured as compared with the case where the height of the bump foil piece 21 is changed between the inner peripheral end side and the outer peripheral end side or the rigidity is changed. In addition, since the dimensional management becomes easy, it is effective for mass production, and the manufacturing cost can be reduced.

  Further, since the shim fixing side 52 of the shim 50 is located on the downstream side in the rotational direction, when the top foil piece 11 is pushed into the thrust collar 4 through the fluid lubrication film, the top foil piece 11 that is vertically stacked is used. And the shim 50 are slid in the direction in which their free ends face each other, that is, in opposite directions (directions of the fixed sides of each other). Therefore, since the relative slip amount between the top foil pieces 11 and the shim 50 increases, a high friction damping effect can be obtained between them.

As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same.
In this way, the inclined surface 32 is formed in each support region 31, 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 made to coincide with the inclination direction of the inclined surface 32. Then, by arranging the top foil piece 11 on the inclined surface 32 via the bump foil piece 21 and the shim 50, the height of the top foil piece 11 can be accurately changed along the inclined surface 32. it can. 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 the thrust bearing of this modified example, in addition to the effect of the fifth embodiment, it is possible to obtain an effect of facilitating the processing, improving the mass productivity, and reducing the cost. 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.

  Further, in the fifth embodiment and the modification thereof, the shim fixed side 52 is disposed so as to overlap the end side 21a (fixed side) of the bump foil piece 21, and the base plate 30 is spot welded together with the end side 21a. It may be fixed to.

  Further, in the fifth embodiment and the modifications thereof, the shim may be formed only by the shim piece 51 as shown in FIG. Even in the shim piece 51, the shim 50 is arranged on the upper side of the bump foil piece 21 like the shim 50 shown in FIG. 11C, so that the downstream side in the rotation direction, that is, the side fixed to the base plate 30 is It is bent. As a result, the upstream side in the rotational direction is placed on the peak portion 23 of the bump foil piece 21. The end side on the upstream side in the rotational direction is a free end that is supported on the crest 23 of the bump foil piece 21 without being fixed.

  When such a shim consisting only of the shim piece 51 is used, the shape of the shim (the shim piece 51) is simple, so that an effect that the handleability as a part is good is obtained. Moreover, although the part fixed to the base plate 30 is shorter than the length of the bump foil piece 21 or the top foil piece 11, the shim piece 51 is fixed to the base plate 30 independently by spot welding or the like, so that it is fixed well without any trouble. The That is, when the portion to which the shim piece 51 is fixed is overlapped and fixed to the end side 21 a of the bump foil piece 21 or the fixed side 12 of the top foil piece 11, a step at the fixing portion is caused by the difference in length in the radial direction. Will be formed. However, in this example, since the shim piece 51 is fixed to the base plate 30 independently, such a step is not formed, and inconveniences such as poor welding due to the step are avoided.

“Sixth Embodiment”
Next, 6th Embodiment of the thrust bearing 3 of this invention is described with reference to FIG. 13, FIG. 14 (a)-(d). 13 is a plan view of the thrust bearing, FIG. 14A is a cross-sectional view taken along line FF in FIG. 13, FIG. 14B is a plan view of the bump foil piece, and FIG. FIG. 14D is a plan view and FIG. 14D is an explanatory diagram in which the plan view and the side view are associated with each other in order to explain the shape of the bump foil piece and the shim. The thrust bearing 3F (3) of the sixth embodiment is mainly different from the thrust bearing 3E (3) of the fifth embodiment in that the shim 50 is downstream in the rotational direction of the rotary shaft 1 as shown in FIG. The side shim fixing side 52 is fixed to the base plate 30 together with the fixing side 12 of the top foil piece 11.

  That is, six shims 50 in the present embodiment are also provided in the circumferential direction of the base plate 30 corresponding to the six support regions 31 shown in FIG. 13, and as shown in FIGS. 14 (c) and 14 (d). The shim piece 51 formed and arranged so as to face the outer peripheral side without facing the inner peripheral side of the bump foil piece 21, and one side in the circumferential direction of the shim piece 51, in this embodiment, the rotating shaft 1 And a shim fixing side 52 integrally formed on the downstream side in the rotation direction.

  Similar to the shim piece 51 of the fifth embodiment, the shim piece 51 is formed in a substantially trapezoidal shape in which a fan-shaped apex side is cut out and an inner peripheral side and an outer peripheral side are respectively arc-shaped. Also in the present embodiment, the portion facing the two bump foil divided pieces 21b on the inner peripheral side of the bump foil piece 21 is cut out, and the two bump foil divided pieces 21b on the outer peripheral side are not opposed to this. Oppositely, it is arrange | positioned in contact with the ridgeline (top part) of the peak part, ie, the peak part 23, and.

  Further, the shim 50 is formed longer on the downstream side in the rotational direction than the shim 50 of the fifth embodiment shown in FIGS. 10 and 11A to 11D, and its end side, that is, the shim fixing side 52. However, as shown in FIGS. 13 and 14 (a), the top foil piece 11 adjacent to the downstream side in the rotation direction is spot welded (dot welded) to the base plate 30 together with the fixed side 12, and fixed. 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 3 </ b> F (3) of the present embodiment, the shim piece 51 (the shim 50) is disposed between the top foil piece 11 and the bump foil piece 21. It is possible to prevent the end side from rising to the thrust collar 4 side, and therefore, on the downstream end side of the top foil piece 11, the film thickness of the fluid lubricating film on the inner peripheral end side is prevented from becoming extremely thin. can do. Therefore, the thrust bearing 3F (3) can also prevent the top foil piece 11 from coming into contact with the thrust collar 4 on the inner peripheral end side, and is excellent in being able to withstand a high load.

  In addition, the shim piece 51 is disposed without changing the height of the bump foil piece 21 between the inner peripheral end side and the outer peripheral end side, thereby preventing the top foil piece 11 from rising on the inner peripheral end side. Therefore, compared to the case where rising is prevented by changing the height of the bump foil piece 21, the difference in the supporting force between the inner and outer circumferences of the top foil piece 11 can be easily and accurately created. it can. Accordingly, the thrust bearing 3F (3) can be designed and manufactured more easily than when the height of the bump foil piece 21 is changed between the inner peripheral end side and the outer peripheral end side or the rigidity is changed. In addition, since the dimensional management becomes easy, it is effective for mass production, and the manufacturing cost can be reduced.

  Further, since the shim fixing side 52 is fixed to the base plate 30 together with the fixing side 12 of the top foil piece 11 adjacent to the downstream side in the rotation direction, the top foil piece 11 is pushed into the thrust collar 4 through the fluid lubricating film. At this time, the top foil piece 11 and the shim 50 stacked one above the other slide in the direction in which their free ends face each other, that is, in opposite directions (directions of fixed sides). Therefore, since the relative slip amount between the top foil pieces 11 and the shim 50 increases, a high friction damping effect can be obtained between them.

As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same.
In this way, the inclined surface 32 is formed in each support region 31, 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 made to coincide with the inclination direction of the inclined surface 32. Then, by arranging the top foil piece 11 on the inclined surface 32 via the bump foil piece 21 and the shim 50, the height of the top foil piece 11 can be accurately changed along the inclined surface 32. it can. 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 the thrust bearing of this modified example, in addition to the effect of the sixth embodiment, it is possible to obtain an effect of facilitating the processing, improving the mass productivity, and reducing the cost. 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.

  Next, seventh to twelfth embodiments of the thrust bearing 3 of the present invention will be described. The seventh to twelfth embodiments are embodiments corresponding to the first to sixth embodiments, respectively, and the shape of the shim is changed with respect to the first to sixth embodiments. It differs only in respect. That is, the shim 55 of the seventh to twelfth embodiments is formed by cutting the shim piece 56 not only in the inner peripheral side region of the bump foil piece 21 (back foil piece) but also in the outer peripheral side region. Has been.

“Seventh Embodiment”
As described above, the thrust bearing of the seventh embodiment is an embodiment corresponding to the first embodiment, and differs from the thrust bearing 3A (3) of the first embodiment in FIGS. 15 (a) to 15 (d). As shown in FIG. 15A to 15D are views showing a seventh embodiment of the thrust bearing according to the present invention, and FIG. 15A is a cross-sectional view corresponding to the cross-sectional view taken along the line AA in FIG. FIG. 15B is a plan view of the bump foil piece, FIG. 15C is a plan view of the shim, and FIG. 15D is a plan view and a side view for explaining the shape of the bump foil piece and the shim. It is explanatory drawing which made these correspond.

  As shown in FIG. 15C, the shim 55 of this embodiment is integrally formed with the shim piece 56 and one side in the circumferential direction of the shim piece 56, in this embodiment, on the downstream side in the rotation direction of the rotary shaft 1. The shim fixing side 57 is made of. In the present embodiment and the eighth to twelfth embodiments described later, the shim fixing side 57 is the bump foil piece 21 (back foil piece) or the top foil, as in the first to seventh embodiments. The length of the piece 11 is the same as the length in the radial direction.

  The shim piece 56 is formed in a substantially trapezoidal shape in which both the apex side and the outer peripheral side of the sector are cut out, and the inner peripheral side and the outer peripheral side are respectively arc-shaped. That is, in this embodiment, as shown in FIG. 15D, shim pieces 56 are formed and arranged so as to face the intermediate region in the radial direction of the bump foil piece 21. Therefore, the shim piece 56 is disposed so as to face the middle region of the bump foil piece 21 and in contact with the bottom, that is, the valley 22.

  The radial length L1 of the shim piece 56 cut out on the inner peripheral side with respect to the shim fixing side 57 is 0.2L or more and 0.5L when the radial length of the shim fixing side 57 is L. The following is assumed. Further, the length L2 in the radial direction cut out on the outer peripheral side is set to about 0.05L to 0.3L. Here, the reason why the shim piece 56 is formed by notching the outer peripheral side of the shim fixing side 57 is as follows.

  On the outer peripheral side of the top foil 10 (top foil piece 11), the pressure of the fluid lubricating film is the same as the ambient pressure (for example, atmospheric pressure) at the outer peripheral end. Is lower than the other outer peripheral side (placed inward from the outer peripheral end). For this reason, the top foil 10 (top foil piece 11) rises not only at its inner peripheral end but also at the outer peripheral end, and this outer peripheral end may also be locally worn.

Thus, in the present embodiment, as described above, the shim piece 56 is formed by notching the bump foil piece 21 on the outer peripheral side without facing the bump foil piece 21, thereby rising at the outer peripheral end of the top foil piece 11. It also prevents.
As for the shim piece 56, not only the inner peripheral side but also the outer peripheral side is not completely cut out, and at least it does not face the valley 22 which is the bottom of the bump foil piece 21. A part thereof may be left in the outer peripheral side region of the bump foil piece 21. Specifically, a portion facing the peak 23 excluding the valley 22 may be left in a comb shape. Even if a portion facing the peak portion 23 is left in this way, this portion is not directly in contact with the bump foil piece 21 and is opposed to the peak portion 23 with a gap, so that the shim piece is shown in FIG. As in the shim piece 56 shown in FIG. 1, only the intermediate region of the bump foil piece 21 is lifted and supported by its thickness, and thus functions in the same manner as the shim piece 56.

  In the thrust bearing of this embodiment, since the shim piece 56 (shim 55) is disposed between the bump foil piece 21 and the base plate 30, the thrust collar on the inner peripheral end side of the top foil piece 11 is disposed. In addition to preventing the top foil piece 11 from rising up, it is possible to prevent the top foil piece 11 from rising up to the thrust collar 4 side. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side and the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

“Eighth Embodiment”
As described above, the thrust bearing of the eighth embodiment is an embodiment corresponding to the second embodiment. The thrust bearing of the eighth embodiment is mainly different from the thrust bearing 3 of the seventh embodiment as shown in FIGS. 5A to 5C of the second embodiment. The point where the inclined surface 32 is formed in the region 31 is the same as the height of the peak portion 23 of the bump foil piece 21. That is, also in this embodiment, the shim 55 having the shim piece 56 having the shape shown in FIG.

  Accordingly, even in the thrust bearing of the present embodiment, the shim piece 56 (the shim 55) is disposed between the bump foil piece 21 and the base plate 30, and therefore, on the inner peripheral end side of the top foil piece 11, It is possible to prevent the rising to the thrust collar 4 side and to prevent the outer peripheral end of the top foil piece 11 from rising to the thrust collar 4 side. Thereby, in the downstream edge side of the top foil piece 11, it can prevent that the film thickness of the fluid lubricating film in an inner peripheral end side and the fluid lubricating film in an outer peripheral end side becomes extremely thin. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

  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. Since they are matched, machining can be facilitated and mass productivity can be improved, and costs can be reduced, similarly to the thrust bearing 3B (3) of the second embodiment.

“Ninth Embodiment”
As described above, the thrust bearing of the ninth embodiment is an embodiment corresponding to the third embodiment. FIGS. 16A to 16D are views showing a ninth embodiment of the thrust bearing according to the present invention, and FIG. 16A is a cross-sectional view corresponding to the cross-sectional view taken along the line CC in FIG. FIG. 16B is a plan view of the bump foil piece, FIG. 16C is a plan view of the shim, and FIG. 16D is a plan view and a side view for explaining the shapes of the bump foil piece and the shim. It is explanatory drawing which made these correspond. The thrust bearing of the ninth embodiment is mainly different from the thrust bearing 3 of the seventh embodiment in that the shim fixing side 52 of the shim 50 is located upstream in the rotational direction of the rotary shaft 1 as shown in FIG. It is a point that is located.

As shown in FIG. 16C, the shim 55 of this embodiment is integrally formed with the shim piece 56 and one side in the circumferential direction of the shim piece 56, in this embodiment, on the upstream side in the rotation direction of the rotating shaft 1. The shim fixing side 57 is made of.
The shim piece 56 is formed in a substantially trapezoidal shape in which both the apex side and the outer peripheral side of the sector are cut out, and the inner peripheral side and the outer peripheral side are respectively arc-shaped. That is, also in this embodiment, as shown in FIG. 16D, the shim pieces 56 are formed and arranged so as to face the intermediate region in the radial direction of the bump foil piece 21. Therefore, the shim piece 56 is disposed so as to face the middle region of the bump foil piece 21 and in contact with the bottom, that is, the valley 22.

Also in the present embodiment, the shim fixing side 57 is formed to have the same length as the radial length of the bump foil piece 21 (back foil piece) or the top foil piece 11.
Similarly to the seventh embodiment, the radial length L1 in which the shim piece 56 is cut out on the inner peripheral side with respect to the shim fixing side 57 is L. The radial length of the shim fixing side 57 is L. Then, it is about 0.2L or more and 0.5L or less. Further, the length L2 in the radial direction cut out on the outer peripheral side is set to about 0.05L to 0.3L.

  Even in the thrust bearing of this embodiment, since the shim piece 56 (shim 55) is disposed between the bump foil piece 21 and the base plate 30, the thrust collar on the inner peripheral end side of the top foil piece 11 is disposed. In addition to preventing the top foil piece 11 from rising up, it is possible to prevent the top foil piece 11 from rising up to the thrust collar 4 side. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side and the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

  As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same. In that case, similarly to the thrust bearing 3B (3) of the second embodiment, it is possible to facilitate the processing, improve the mass productivity, and reduce the cost.

“Tenth Embodiment”
As described above, the thrust bearing of the tenth embodiment is an embodiment corresponding to the fourth embodiment. FIGS. 17A to 17D are views showing a tenth embodiment of the thrust bearing according to the present invention, and FIG. 17A is a cross-sectional view corresponding to the cross-sectional view taken along the line DD in FIG. FIG. 17B is a plan view of the bump foil piece, FIG. 17C is a plan view of the shim, and FIG. 17D is a plan view and a side view for explaining the shape of the bump foil piece and the shim. It is explanatory drawing which made these correspond. The thrust bearing of the tenth embodiment is mainly different from the thrust bearing 3 of the ninth embodiment in that the shim 55 has a top foil piece 11 and a bump foil piece 21 (back foil piece) as shown in FIG. It is the point arrange | positioned between.

As shown in FIG. 17C, the shim 55 of this embodiment is integrally formed with the shim piece 56 and one side in the circumferential direction of the shim piece 56, in this embodiment, on the upstream side in the rotation direction of the rotary shaft 1. The shim fixing side 57 is made of.
The shim piece 56 is formed in a substantially trapezoidal shape in which both the apex side and the outer peripheral side of the sector are cut out, and the inner peripheral side and the outer peripheral side are respectively arc-shaped. That is, also in this embodiment, as shown in FIG. 17D, the shim pieces 56 are formed and arranged so as to face the intermediate region in the radial direction of the bump foil piece 21. Therefore, the shim piece 56 is disposed so as to face the intermediate region of the bump foil piece 21 and to be in contact with the topmost portion thereof, that is, the ridge line (top portion) of the peak portion 23.

Also in the present embodiment, the shim fixing side 57 is formed to have the same length as the radial length of the bump foil piece 21 (back foil piece) or the top foil piece 11.
Similarly to the seventh embodiment, the radial length L1 in which the shim piece 56 is cut out on the inner peripheral side with respect to the shim fixing side 57 is L. The radial length of the shim fixing side 57 is L. Then, it is about 0.2L or more and 0.5L or less. Further, the length L2 in the radial direction cut out on the outer peripheral side is set to about 0.05L to 0.3L.

  In the thrust bearing of the present embodiment, since the shim piece 56 (shim 55) is disposed between the top foil piece 11 and the bump foil piece 21, the inner peripheral end side of the top foil piece 11, It is possible to prevent the rising to the thrust collar 4 side and to prevent the outer peripheral end of the top foil piece 11 from rising to the thrust collar 4 side. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side and the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

  As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same. In that case, similarly to the thrust bearing 3B (3) of the second embodiment, it is possible to facilitate the processing, improve the mass productivity, and reduce the cost.

“Eleventh Embodiment”
As described above, the thrust bearing of the eleventh embodiment is an embodiment corresponding to the fifth embodiment. FIGS. 18A to 18D are views showing an eleventh embodiment of the thrust bearing according to the present invention, and FIG. 18A is a cross-sectional view corresponding to the cross-sectional view taken along the line EE in FIG. FIG. 18B is a plan view of the bump foil piece, FIG. 18C is a plan view of the shim, and FIG. 18D is a plan view and a side view for explaining the shape of the bump foil piece and the shim. It is explanatory drawing which made these correspond. The thrust bearing of the eleventh embodiment is mainly different from the thrust bearing 3 of the tenth embodiment in that the shim fixing side 57 of the shim 55 is located downstream in the rotational direction of the rotary shaft 1 as shown in FIG. It is a point that is located.

As shown in FIG. 18C, the shim 55 of this embodiment is formed integrally with the shim piece 56 and one side in the circumferential direction of the shim piece 56, in this embodiment, on the downstream side in the rotation direction of the rotary shaft 1. The shim fixing side 57 is made of.
The shim piece 56 is formed in a substantially trapezoidal shape in which both the apex side and the outer peripheral side of the sector are cut out, and the inner peripheral side and the outer peripheral side are respectively arc-shaped. That is, also in this embodiment, as shown in FIG. 18D, the shim pieces 56 are formed and arranged so as to face the intermediate region in the radial direction of the bump foil piece 21. Therefore, the shim piece 56 is disposed so as to be opposed to the intermediate region of the bump foil piece 21 and in contact with the topmost portion thereof, that is, the ridge line of the peak portion 23.

Also in the present embodiment, the shim fixing side 57 is formed to have the same length as the radial length of the bump foil piece 21 (back foil piece) or the top foil piece 11.
Similarly to the seventh embodiment, the radial length L1 in which the shim piece 56 is cut out on the inner peripheral side with respect to the shim fixing side 57 is L. The radial length of the shim fixing side 57 is L. Then, it is about 0.2L or more and 0.5L or less. Further, the length L2 in the radial direction cut out on the outer peripheral side is set to about 0.05L to 0.3L.

  Even in the thrust bearing of the present embodiment, since the shim piece 56 (shim 55) is disposed between the top foil piece 11 and the bump foil piece 21, the inner peripheral end side of the top foil piece 11, It is possible to prevent the rising to the thrust collar 4 side and to prevent the outer peripheral end of the top foil piece 11 from rising to the thrust collar 4 side. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side and the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

  As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same. In that case, similarly to the thrust bearing 3B (3) of the second embodiment, it is possible to facilitate the processing, improve the mass productivity, and reduce the cost.

  Further, in the fifth embodiment and its modification, as shown in FIG. 12, the shim is formed only by the shim piece 51, and also in the eleventh embodiment and its modification, FIG. It is possible to use only the shim piece 56 shown in FIG. When such a shim consisting only of the shim pieces 56 is used, the shape of the shim (the shim piece 56) is simple, so that an effect of good handling as a part can be obtained.

“Twelfth Embodiment”
As described above, the thrust bearing of the twelfth embodiment is an embodiment corresponding to the sixth embodiment. FIGS. 19A to 19D are views showing a twelfth embodiment of the thrust bearing according to the present invention, and FIG. 19A is a cross-sectional view corresponding to the cross-sectional view taken along line FF in FIG. FIG. 19B is a plan view of the bump foil piece, FIG. 19C is a plan view of the shim, and FIG. 19D is a plan view and a side view for explaining the shape of the bump foil piece and the shim. It is explanatory drawing which made these correspond. The thrust bearing of the twelfth embodiment differs from the thrust bearing 3 of the eleventh embodiment mainly in that the shim fixing side 57 of the shim 55 on the downstream side in the rotation direction of the rotating shaft 1 is as shown in FIG. The top foil piece 11 is fixed to the base plate 30 together with the fixed side 12 of the top foil piece 11.

As shown in FIG. 19C, the shim 55 of this embodiment is formed integrally with the shim piece 56 and one side in the circumferential direction of the shim piece 56, in this embodiment, on the downstream side in the rotation direction of the rotary shaft 1. The shim fixing side 57 is made of.
The shim piece 56 is formed in a substantially trapezoidal shape in which both the apex side and the outer peripheral side of the sector are cut out, and the inner peripheral side and the outer peripheral side are respectively arc-shaped. That is, also in this embodiment, as shown in FIG. 19D, the shim pieces 56 are formed and arranged so as to face the intermediate region in the radial direction of the bump foil piece 21. Therefore, the shim piece 56 is disposed so as to be opposed to the intermediate region of the bump foil piece 21 and in contact with the topmost portion thereof, that is, the ridge line of the peak portion 23.

Also in the present embodiment, the shim fixing side 57 is formed to have the same length as the radial length of the bump foil piece 21 (back foil piece) or the top foil piece 11.
Similarly to the seventh embodiment, the radial length L1 in which the shim piece 56 is cut out on the inner peripheral side with respect to the shim fixing side 57 is L. The radial length of the shim fixing side 57 is L. Then, it is about 0.2L or more and 0.5L or less. Further, the length L2 in the radial direction cut out on the outer peripheral side is set to about 0.05L to 0.3L.

  Even in the thrust bearing of the present embodiment, since the shim piece 56 (shim 55) is disposed between the top foil piece 11 and the bump foil piece 21, the inner peripheral end side of the top foil piece 11, It is possible to prevent the rising to the thrust collar 4 side and to prevent the outer peripheral end of the top foil piece 11 from rising to the thrust collar 4 side. Therefore, it is possible to prevent the film thickness of the fluid lubricating film on the inner peripheral end side and the fluid lubricating film on the outer peripheral end side from becoming extremely thin on the downstream end side of the top foil piece 11. Therefore, the thrust bearing can prevent the top foil piece 11 from coming into contact with the thrust collar 4 on both the inner peripheral end side and the outer peripheral end side, and is excellent in being able to withstand a high load.

  As a modification of the present embodiment, an inclined surface 32 is formed in the support region 31 of the base plate 30 of the present embodiment, and the bump foil pieces 21 are stacked as in the second embodiment relative to the first embodiment. You may make all the height of the part 23 the same. In that case, similarly to the thrust bearing 3B (3) of the second embodiment, it is possible to facilitate the processing, improve the mass productivity, and reduce the cost.

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 and the top foil 10 are each composed of six back foil pieces 21 (bump foil pieces 21) and top foil pieces 11, and six shims 50 (55) are also used. The six support regions 31 were also formed (set) accordingly. However, the back foil piece 21 (bump foil piece 21), the top foil piece 11, and the shim 50 (55) may be five or less if the number is plural. There may be more than one. In this case, the number of support regions 31 is naturally adjusted to the number of back foil pieces 21 (bump foil pieces 21), top foil pieces 11, and shims 50 (55).

  Moreover, in the said embodiment, although the bump foil piece 21 (back foil piece 21) was formed by the four bump foil division pieces 21b and the continuous side (fixed side), about each division piece, it is limited to four. There may be any number of 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, although the slit 21c formed by dividing | segmenting the bump foil piece 21 (back foil piece 21) into multiple in radial direction was formed in circular arc shape, this slit 21c is formed in linear form, for example May be.
Further, the bump foil piece 21 (back foil piece 21) is not divided into a plurality of bump foil divided pieces 21b by dividing the bump foil piece 21 in the radial direction. The foil piece 21 (back foil piece 21) may be formed.

  In addition to the above-described embodiments, various forms such as a top foil piece, a bump foil piece, a shim shape, a top foil piece, a bump foil piece on the support region, a shim arrangement, and an inclined direction of the inclined surface are adopted. It is possible.

DESCRIPTION OF SYMBOLS 1 ... Rotary shaft 3, 3A, 3B, 3C, 3D, 3E, 3F ... 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 ... Slit, 22 ... Valley, 23 ... Mountain, 30 ... base plate, 31 ... support region, 32 ... inclined surface, 50, 55 ... shim, 51, 56 ... shim piece, 52, 57 ... shim fixed side

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,
The back foil piece is divided into a plurality in the radial direction on at least one side in the circumferential direction,
Between the back foil piece and the base plate, it faces at least the intermediate region in the radial direction of the back foil piece without facing at least the bottommost part of the back foil piece in the inner peripheral region of the back foil piece. A thrust bearing, wherein shim pieces are arranged.   The thrust bearing according to claim 1, wherein the shim piece is formed so as not to face at least the bottommost part of the back foil piece in an outer peripheral side region of the back foil piece. 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,
The back foil piece is divided into a plurality in the radial direction on at least one side in the circumferential direction,
Between the top foil piece and the back foil piece, an intermediate region at least in the radial direction of the back foil piece without facing at least the topmost part of the back foil piece in the inner peripheral region of the back foil piece. A thrust bearing characterized in that a shim piece is disposed opposite to the bearing.   4. The thrust bearing according to claim 3, wherein the shim piece is formed so as not to face at least the topmost portion of the back foil piece in the outer peripheral side region of the back foil piece.   5. The back foil piece according to claim 1, wherein 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. The thrust bearing according to any one of the above.   The shim piece is integrally formed with a shim fixing side fixed to the base plate on one side in the circumferential direction, and the shim fixing side is a length in a radial direction of the back foil piece or the top foil piece. The thrust bearing according to any one of claims 1 to 5, wherein the thrust bearing is formed to have the same length as that of the thrust bearing.

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