WO2014115847A1 - スラスト軸受 - Google Patents
スラスト軸受 Download PDFInfo
- Publication number
- WO2014115847A1 WO2014115847A1 PCT/JP2014/051561 JP2014051561W WO2014115847A1 WO 2014115847 A1 WO2014115847 A1 WO 2014115847A1 JP 2014051561 W JP2014051561 W JP 2014051561W WO 2014115847 A1 WO2014115847 A1 WO 2014115847A1
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- WO
- WIPO (PCT)
- Prior art keywords
- top foil
- foil piece
- fixed
- base plate
- thrust bearing
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C27/00—Elastic or yielding bearings or bearing supports, for exclusively rotary movement
- F16C27/08—Elastic or yielding bearings or bearing supports, for exclusively rotary movement primarily for axial load, e.g. for vertically-arranged shafts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/04—Sliding-contact bearings for exclusively rotary movement for axial load only
- F16C17/042—Sliding-contact bearings for exclusively rotary movement for axial load only with flexible leaves to create hydrodynamic wedge, e.g. axial foil bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/16—Arrangement of bearings; Supporting or mounting bearings in casings
- F01D25/166—Sliding contact bearing
- F01D25/168—Sliding contact bearing for axial load mainly
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C27/00—Elastic or yielding bearings or bearing supports, for exclusively rotary movement
- F16C27/02—Sliding-contact bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2220/00—Application
- F05D2220/40—Application in turbochargers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/50—Bearings
- F05D2240/52—Axial thrust bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2360/00—Engines or pumps
Definitions
- the present invention relates to a thrust bearing.
- This application claims priority based on Japanese Patent Application No. 2013-013170 for which it applied to Japan on January 28, 2013, and uses the content here.
- a thrust bearing that is arranged to face a thrust collar provided on a rotating shaft and supports the thrust collar.
- a foil-type thrust bearing that is, a thrust foil bearing is well known.
- This thrust foil bearing is formed of a flexible foil (thin metal plate) on the bearing surface so that it can absorb the movement of the rotating shaft (axial displacement and inclination of the thrust collar) generated by vibration and impact.
- a foil structure for flexibly supporting the bearing surface is provided under the surface.
- an annular (annular) bearing surface is formed by a plurality of foil pieces (top foil pieces) obtained by dividing an annular plate in the circumferential direction.
- a structure supported by corrugated foil pieces (bump foil pieces) is known (for example, see Patent Document 1).
- Each top foil piece (thickness of about 100 ⁇ m) is arranged with an inclination angle with respect to the thrust collar, whereby the bearing gap between the thrust collar and the top foil piece is formed in a wedge shape in side view. The 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 wide bearing clearance side (upstream side) toward the narrow bearing clearance side (downstream side), the lubricating fluid flows into the narrow portion of the wedge-shaped bearing clearance, and the bearing load capacity is demonstrated. Is done.
- the top foil piece In the top foil piece, only the edge on the upstream side in the rotation direction of the thrust collar (rotating shaft) is fixed to the base plate, and this edge is configured as a fixed edge.
- the top foil When the bearing load increases, the top foil is displaced horizontally (parallel to the supported surface of the thrust collar) with this fixed side (upstream end side) as a fulcrum, and the inclination angle decreases, and the inclination angle becomes The thrust bearing generates the maximum load capacity when it reaches about 0.1 °.
- 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 fixed to the base plate. Has been. That is, the upstream end of the bump foil piece is a free end.
- the bump foil piece Since the bump foil piece is arranged and fixed in this way, 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. Therefore, the load capacity of the bearing can be increased by supporting this portion with high rigidity.
- the bearing gap is narrowest at the downstream end of the top foil piece, and the gap at this position may reach submicron when the load is high. That is, the contact between the top foil piece and the thrust collar easily occurs at the position of the downstream side edge, and if the contact occurs, the top foil or the like is damaged and the bearing life is shortened. In the worst case, seizure may occur. There is sex.
- the present invention has been made in view of the above circumstances, and the thrust bearing in which the downstream side edge of the top foil piece and the vicinity thereof are prevented from coming into contact with the thrust collar, thereby preventing a reduction in bearing life, seizure and the like.
- the purpose is to provide.
- the present inventor has obtained the following knowledge.
- the downstream side edge which is the free end of the top foil piece
- the distance between the upstream side edge, which is a fixed side fixed to the base plate, and the downstream side edge, which is a free end gradually increases from the inner side toward the outer side in the radial direction of the base plate. For this reason, the outer periphery of the top foil piece is longer than the inner periphery.
- the inner periphery is displaced more than the inner peripheral edge. Therefore, when the top foil piece is displaced, there may be a difference in the height between the portion near the outer peripheral edge and the portion near the inner peripheral edge of the downstream end that is the free end. That is, the length of the outer peripheral edge of the top foil piece (the distance between the upstream side edge and the downstream side edge) is the length of the inner peripheral edge (the distance between the upstream side edge and the downstream side edge).
- the displacement amount of the portion near the outer peripheral edge is larger than the displacement amount of the portion near the inner peripheral edge at the downstream side edge. Therefore, when the top foil piece is displaced with the fixed side as a fulcrum, the portion near the outer peripheral edge or the portion near the inner peripheral edge of the downstream side edge may easily come into contact with the thrust collar.
- the downstream side edge that is the free end of the top foil piece is arranged non-parallel to the thrust collar, the bearing gap (particularly the side where the bearing gap is narrow) changes in the radial direction of the base plate. It may not be possible to secure the load capacity of the correct bearing.
- the top foil piece is inclined due to an increase in load. If the angle is reduced, the parallel state between the downstream side edge and the thrust collar may be broken. As a result of further earnest studies based on such knowledge, the present inventor completed the present invention.
- the thrust bearing disposed opposite to the thrust collar provided on the rotating shaft includes a top foil disposed opposite to the thrust collar, and the top foil including the top foil, A back foil that is disposed opposite to a surface opposite to a surface that faces the thrust collar, and that supports the top foil, and is disposed on a side of the back foil opposite to the side closer to the top foil, And an annular base plate for supporting the back foil.
- the back foil has a plurality of back foil pieces arranged in the circumferential direction of the base plate, and the top foil has a plurality of top foil pieces respectively disposed on the plurality of back foil pieces.
- a fixing portion that is fixed to the base plate is formed on a portion of the top foil piece on the upstream side in the rotation direction of the rotation shaft.
- the fixed side of the fixed portion that is located on the downstream side in the rotation direction of the rotating shaft extends linearly so as to approach the downstream side in the rotation direction of the rotating shaft from the inner side toward the outer side in the radial direction of the base plate. , Inclined with respect to the straight line extending in the radial direction.
- the fixed side in the fixed portion fixed to the base plate extends linearly so as to approach the downstream side in the rotational direction of the rotation shaft from the radially inner side to the outer side of the base plate. , Inclined with respect to the straight line extending in the radial direction. For this reason, the length of the outer peripheral edge of the top foil piece (the distance between the upstream side edge and the downstream side edge) is the length of the inner peripheral edge (the distance between the upstream side edge and the downstream side edge).
- the top foil piece is displaced (rotated) away from or close to the base plate with the fixed side as a fulcrum (rotation center), even if the inclination angle changes, the top foil piece is outside the downstream side edge. It is possible to prevent the portion near the periphery from being largely displaced as compared with the portion near the inner periphery. Therefore, even if the inclination angle of the top foil piece changes, the downstream side edge, which is the free end of the top foil piece, can maintain a state that is nearly parallel to the thrust collar.
- the fixed side is a position between both ends of the first end side that is located upstream in the rotation direction of the rotary shaft in the top foil piece.
- the rigidity of a fixed side vicinity is reduced by shortening the length of a fixed side, and it becomes easy to displace a top foil piece by using a fixed side as a fulcrum. Therefore, for example, when the thrust collar is sandwiched between the pair of top foils, the starting torque is reduced. Further, since the top foil piece is easily and smoothly displaced even after the rotation shaft starts to rotate, the optimum inclination angle of the top foil piece is easily obtained, and the load capacity of the bearing is improved.
- the first end of the top foil piece on the upstream side in the rotational direction of the rotation shaft extends from the inner edge to the outer edge of the top foil piece. And an outer side extending from the end of the inner side closer to the outer peripheral edge to the outer peripheral edge.
- the fixed side is provided on the outer side.
- the rigidity of the vicinity of the fixed side is reduced by reducing the length of the fixed side, and the top foil piece is easily displaced with the fixed side as a fulcrum. Therefore, for example, when the thrust collar is sandwiched between the pair of top foils, the starting torque is reduced. Further, since the top foil piece is easily and smoothly displaced even after the rotation shaft starts to rotate, the optimum inclination angle of the top foil piece is easily obtained, and the load capacity of the bearing is improved.
- the fixed side is parallel to a second end side of the top foil piece on the downstream side in the rotational direction of the rotary shaft. Is formed.
- the thrust load changes during the rotation of the thrust collar.
- the downstream side edge which is the free end of the top foil piece is always parallel to the thrust collar (the supported surface of the thrust collar).
- the top foil piece in the thrust bearing according to any one of the first to fourth aspects, is located in the vicinity of the fixed side on the downstream side in the rotation direction of the rotating shaft. It has a thin portion formed thinner than other portions of the foil piece. According to the fifth aspect of the present invention, since the thin portion is formed in the vicinity of the fixed side, the portion of the top foil piece on the downstream side in the rotational direction of the rotating shaft is displaced more easily and smoothly than the thin portion. it can. Therefore, for example, when the thrust collar is sandwiched between the pair of top foils, the starting torque is reduced. Further, since the top foil piece is easily and smoothly displaced even after the rotation shaft starts to rotate, the optimum inclination angle of the top foil piece is easily obtained, and the load capacity of the bearing is improved.
- the back foil piece has a corrugated plate shape in which a plurality of crests and a plurality of troughs are alternately formed. And the adjacent directions of the plurality of peaks are arranged so as to intersect the extending direction of the fixed side. In addition, the height of the plurality of peak portions gradually increases from the end portion of the back foil piece located near the fixed side toward the downstream side in the rotation direction of the rotation shaft. According to the sixth aspect of the present invention, the top foil piece can be elastically supported by the bump foil piece.
- the base plate is provided with a plurality of support regions that respectively support the plurality of back foil pieces, In the support region, an inclined surface is formed in which the height gradually increases from the position where the fixed side is provided toward the end side on the downstream side in the rotation direction of the rotary shaft.
- the height of the top foil piece can be accurately changed along the inclined surface. it can. Further, at this time, the back foil piece may be produced at a constant height without changing its height, and therefore the processing cost can be suppressed.
- the back foil piece in the thrust bearing of the seventh aspect, is formed in a corrugated plate shape in which a plurality of crests and a plurality of troughs are alternately formed, and It arrange
- the top foil piece can be elastically supported by the bump foil piece.
- the bump foil piece is fixed to the base plate at an end on the downstream side in the rotation direction of the rotation shaft.
- the rotational direction of the bearing gap is set so that the pressure of the fluid lubricating film generated on the top foil piece is increased on the narrow side of the bearing gap, that is, on the downstream side in the rotational direction of the rotary shaft.
- the downstream portion can be supported with high rigidity, thereby increasing the load capacity of the bearing.
- the thrust bearing of the present invention it is possible to maintain the downstream side edge, which is the free end of the top foil piece, in a state almost parallel to the thrust collar. Therefore, it is possible to prevent the downstream end side and the vicinity thereof from coming into contact with the thrust collar, thereby preventing a decrease in bearing life and seizure.
- FIG. 3B is a cross-sectional view taken along line 3B-3B in FIG. 3A.
- FIG. 1 shows 1st Embodiment of the thrust bearing which concerns on this invention, and is the explanatory drawing which matched the top view and the side view in order to demonstrate the shape of a bump foil piece.
- It is a top view of a top foil piece for showing the modification about the shape of a top foil piece, a fixed side, the shape of a fixed part, etc.
- It is a top view of a top foil piece for showing the modification about the shape of a top foil piece, a fixed side, the shape of a fixed part, etc.
- FIG. 5B is a cross-sectional view taken along line 5B-5B in FIG. 5A. It is a figure which shows 2nd Embodiment of the thrust bearing which concerns on this invention, In order to demonstrate the shape of a bump foil piece, it is explanatory drawing which matched the top view and the side view.
- 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.
- reference numeral 1 denotes a rotating shaft
- reference numeral 2 denotes an impeller provided at a tip portion of the rotating shaft
- Reference numeral 3 denotes a thrust bearing according to the present invention.
- a thrust collar 4 is fixed to the rotary shaft 1 in the vicinity of the tip where the impeller 2 is formed.
- a pair of thrust bearings 3 is arranged so as to sandwich the thrust collar 4.
- the impeller 2 is disposed in the housing 5 on the stationary side, and a tip clearance 6 is formed between the impeller 2 and the housing 5.
- the rotary shaft 1 is provided with a radial bearing 7 in a portion closer to the center than the thrust collar 4.
- FIG. 2 and 3A to 3C are views showing a first embodiment of the thrust bearing 3 applied to the turbomachine having such a configuration.
- FIG. 2 is a side view of the thrust bearing 3 with the thrust collar 4 interposed therebetween.
- FIG. 3A is a plan view of the thrust bearing 3 partially in cross section.
- 3B is a cross-sectional view taken along line 3B-3B in FIG. 3A.
- FIG. 3C 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.
- the thrust bearings 3A (3) are disposed on both sides of the thrust collar 4, respectively.
- the pair of thrust bearings 3 ⁇ / b> A (3) has the same configuration, and is an annular (cylindrical) device disposed to face the disc-shaped thrust collar 4 fixed to the rotating shaft 1.
- the rotary shaft 1 is surrounded. Both surfaces of the thrust collar 4 (both surfaces in the axial direction of the rotary shaft 1) are configured as supported surfaces, and the pair of thrust bearings 3A (3) are supported so as to face both supported surfaces of the thrust collar 4, respectively.
- the thrust bearing 3A includes a top foil 10 disposed to face the thrust collar 4, and a back foil 20 disposed to face the surface of the top foil 10 opposite to the surface facing the thrust collar 4.
- the back foil 20 includes an annular plate-like base plate 30 disposed on the side opposite to the side closer to the top foil 10.
- the base plate 30 is not limited to an annular plate shape, and may be a cylindrical shape extending in the axial direction of the rotary shaft 1.
- a cylindrical bearing spacer 40 indicated by a two-dot chain line is sandwiched between the base plates 30 and 30 of the pair of thrust bearings 3A and 3A, and the base plates 30 and 30 are supported by fastening bolts 41. They are connected via a spacer 40.
- one base plate 30 is fixed to the housing 5 by fastening bolts 41. Accordingly, the pair of thrust bearings 3 ⁇ / b> A and 3 ⁇ / b> A are fixed to the housing 5 by the fastening bolts 41 with the thrust collar 4 interposed therebetween.
- the base plate 30 is an annular plate-shaped metal member, and a plurality (eight in this embodiment) of through holes 42 through which the fastening bolts 41 are inserted are formed on the outer periphery thereof. ing.
- the base plate 30 is provided with a support region for supporting the back foil 20 and the top foil 10 on the surface facing the thrust collar 4.
- the back foil 20 has a plurality (six) of back foil pieces 21 and the top foil 10 has a plurality of (six) top foil pieces 11 as described later.
- the base plate 30 is formed with six support regions 31 each having a surface divided into six (equally divided into six) in the circumferential direction.
- the six support regions 31 in the present embodiment are designed regions, and the surface of the base plate 30 including these support regions 31 is a uniform plane.
- the back foil piece 21 and the top foil piece 11 are arranged in this order in each support region 31 and supported by the support region 31.
- the base plate 30, the back foil piece 21, and the top foil piece 11 are stacked in the axial direction of the rotating shaft 1.
- the back foil 20 has six back foil pieces 21 arranged in the circumferential direction of the base plate 30. These back foil pieces 21 are respectively arranged on a plurality of support regions 31 of the base plate 30, thereby being arranged in the circumferential direction of the base plate 30. Further, these back foil pieces 21 are formed slightly smaller in plan view than the top foil pieces 11 to be described later, so that the top foil pieces 21 are not exposed to the thrust collar 4 on the base plate 30 as shown in FIG. 3A. Covered with a piece 11.
- 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).
- back foil 20 examples include a bump foil, a spring foil described in Japanese Patent Laid-Open No. 2006-57652, Japanese Patent Laid-Open No. 2004-270904, and Japanese Patent Laid-Open No. 2009-299748.
- the back foil etc. which are described in the gazette etc. are used.
- the spring foil described in Japanese Patent Laid-Open No. 2006-57652 and Japanese Patent Laid-Open No. 2004-270904 and the back foil described in Japanese Patent Laid-Open No. 2009-299748 are used for radial bearings.
- the foil used is a foil used for a thrust bearing if it is developed in a planar shape and formed into a circular plate shape in plan view.
- the back foil 20 is made of a bump foil, and therefore the back foil piece 21 is made of a bump foil piece.
- a foil thin metal plate having a thickness of about several hundreds ⁇ m is formed into a corrugated plate by press forming, and as shown in FIG. It is formed in a pentagon shape.
- the back foil piece 21 thus formed in a corrugated plate shape is formed by alternately arranging valley portions 22 that contact the base plate 30 and peak portions 23 that contact the top foil piece 11.
- the valleys 22 and the peaks 23 are arranged in a direction orthogonal to the extending direction of the fixed side 12 of the top foil piece 11 described later. That is, the arrangement direction of the valley portions 22 and the mountain portions 23 (the direction in which the valley portions 22 and the mountain portions 23 are adjacent, the direction in which the plurality of mountain portions 23 are adjacent) is perpendicular to the extending direction of the fixed side 12. Is formed. Therefore, the trough portion 22 and the crest portion 23 are formed so as to extend in parallel with the fixed side 12, respectively.
- valley portions 22 and peak portions 23 are formed at substantially equal intervals.
- the height of the crest 23 is the opposite direction from the end of the back foil piece 21 located near the fixed side 12, that is, the rotational direction of the rotary shaft 1 (thrust collar 4) indicated by the arrow R in FIG. 3A. It is formed so as to increase by a certain height toward the downstream side (rotation progress side) (see FIG. 3B).
- the back foil piece 21 has an end side 21a on the downstream side in the rotation direction of the rotary shaft 1 and a plan view of an end side 11c (second end side) on the downstream side in the rotation direction of the rotary shaft 1 in the top foil piece 11 described later. In such a state, they are arranged at substantially the same position.
- the back foil piece 21 is spot-welded (dot welded) to the base plate 30 and fixed along the direction of formation of the valley portion 22 that becomes the end side 21a.
- the end side 21a of the back 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 to the base plate 30. Therefore, the back foil piece 21 can be easily fixed by welding.
- the end side 21a can be fixed to the base plate 30 by, for example, screwing in addition to spot welding.
- the top foil 10 is also formed having six top foil pieces 11 arranged in the circumferential direction of the base plate 30 as shown in FIG. 3A.
- These top foil pieces 11 are made of a metal thin plate (foil) having a thickness of about several hundreds ⁇ m, and a portion including the apex is cut out from the fan shape, and the inner peripheral edge (the inner edge in the radial direction of the base plate 30) and the outer
- Each of the peripheral edges (the outer edges in the radial direction of the base plate 30) has an arc shape, and is further formed in a shape in which a portion near the outer peripheral edge of the edge portion on the upstream side in the rotational direction of the rotating shaft 1 (thrust collar 4) is cut out. .
- 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 back 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
- the top foil piece 11 is formed slightly smaller than the support region 31 in plan view and slightly larger than the back foil piece 21 in plan view. As a result, the plurality of top foil pieces 11 are arranged in the respective support regions 31 so as to cover the upper surface without interfering with each other and without exposing the back foil piece 21 toward the thrust collar 4. .
- the present invention is not limited to this, and the top foil piece 11 may be formed in the same size as the back foil piece 21 in plan view, or may be formed smaller than the back foil piece 21 in plan view. Also good.
- a fixed portion 13 is formed on a portion of the top foil piece 11 on the upstream side in the rotation direction of the rotation shaft 1 (thrust collar 4).
- the top foil piece 11 is fixed to the base plate 30 by the fixing portion 13.
- the fixing portion 13 is fixed to the base plate 30 by spot welding (dot welding) in the same manner as the end side 21a of the back foil piece 21.
- the fixing portion 13 can be fixed to the base plate 30 by, for example, screwing in addition to spot welding.
- the fixed portion 13 may be planar or linear as long as it is provided on the upstream side in the rotational direction of the rotary shaft 1 (thrust collar 4). However, in this embodiment, the fixed portion 13 is linear. It is configured as a fixed side 12. That is, the fixed portion 13 and the fixed side 12 of the present embodiment are arranged at the same position, but the fixed side of the present invention is positioned downstream of the fixed portion 13 in the rotation direction of the rotating shaft 1 as will be described later. It is configured as a side to do.
- an end side 11e (first end side) on the upstream side in the rotation direction of the rotating shaft 1 (thrust collar 4) in the top foil piece 11 is an inner side extending from the inner peripheral edge of the top foil piece 11 toward the outer peripheral edge.
- a side 11a and an outer side 11b extending from the end of the inner side 11a near the outer peripheral edge to the outer peripheral edge (radially outer edge) of the top foil piece 11 are formed.
- a fixed side 12 fixed to the base plate 30 is provided on the outer side 11b of the end side 11e.
- the top foil piece 11 has an inner side 11 a out of the end sides 11 e on the upstream side in the rotational direction of the rotary shaft 1 and an end side 11 c (second end side) on the downstream side in the rotational direction of the rotary shaft 1. 1 are arranged so as to substantially coincide with straight lines extending in the radial direction (same as the radial direction of the base plate 30) around the central axis of the rotary shaft 1, that is, around the central axis of the rotary shaft 1. Therefore, the outer side 11b, which becomes the fixed side 12, is arranged such that the rotation shaft 1 approaches the downstream side in the rotation direction of the rotation shaft 1 from the position near the inner periphery of the top foil piece 11 toward the position near the outer periphery.
- the fixed side 12 extends linearly so as to approach the downstream side in the rotational direction of the rotary shaft 1 from the radially inner side to the outer side of the base plate 30, and is flat with respect to the straight line extending in the radial direction of the base plate 30. It is arranged so as to be inclined in view.
- the fixed side 12 is formed in parallel to the end side 11 c of the top foil piece 11 on the downstream side in the rotation direction of the rotary shaft 1.
- fixed part 13, etc. it is not limited to the structure shown to FIG. 3A, A various form is employable.
- a substantially trapezoidal shape (a portion including the apex from the sector shape) is formed without cutting out a portion on the upstream side in the rotation direction of the rotating shaft 1 (thrust collar 4) indicated by an arrow and near the outer peripheral edge.
- the top foil piece 11 is formed in a cut shape
- only the position corresponding to the fixed side 12 shown in FIG. 3A is fixed to the base plate 30 by spot welding or the like, and this fixed point is fixed to the fixed side 12 (fixed portion 13).
- the fixed side 12 is formed to extend from a position between both ends of the end side 11e (first end side) on the upstream side of the rotation axis 1 of the top foil piece 11 to the outer peripheral edge of the top foil piece 11.
- it is formed so as to be inclined with respect to a straight line (end side 11e on the upstream side in the rotation direction) extending in the radial direction of the rotation shaft 1 or the base plate 30.
- the portion 11d located upstream of the fixed side 12 in the rotational direction of the rotary shaft 1 and closer to the outer peripheral edge hardly functions in terms of load capacity.
- the process of notching the part 11d can be omitted, the process can be facilitated and the manufacturing cost can be reduced as compared with the top foil piece 11 shown in FIG. 3A.
- the top foil piece 11 when the top foil piece 11 is formed in a substantially trapezoidal shape without cutting out the portion on the upstream side in the rotation direction of the rotating shaft 1 (thrust collar 4) and near the outer peripheral edge, as shown in FIG. 4B.
- the entire portion including the portion 11 d left without being cut out, that is, the portion 11 d and the fixed side 12 may be used as the fixing portion 13. In this case, spot welding or the like is performed on the entire portion including the portion 11 d and the fixed side 12.
- the fixing portion 13 is formed in this way, the fixing portion 13 is formed including the linear fixed side 12 located on the downstream side in the rotation direction of the rotating shaft 1.
- the fixed side 12 is configured as a side of the fixed unit 13 that is located on the downstream side in the rotation direction of the rotary shaft 1.
- the fixed side 12 extends linearly so as to approach the downstream side in the rotational direction of the rotary shaft 1 from the position near the inner peripheral edge of the top foil piece 11 toward the position near the outer peripheral edge. And inclined with respect to a straight line (an end on the upstream side in the rotational direction) extending in the radial direction.
- FIG. 4 a part of the end of the rotating shaft 1 on the upstream side in the rotation direction, or a portion bent (inclined) from the middle thereof is used as the fixed side 12, but FIG. As shown in FIG. 4, the entire end side on the upstream side in the rotation direction of the rotating shaft 1 may be the fixed side 12. In that case, a portion of the rotating shaft 1 on the upstream side in the rotational direction is cut obliquely, and an end on the upstream side in the rotational direction is formed so as to be inclined with respect to the straight line P1 extending in the radial direction about the rotating shaft 1.
- the upstream side in the rotation direction of the rotating shaft 1 from the fixed side 12 may be left as it is, as indicated by a two-dot chain line in FIG. 4C. Moreover, it is good also as the fixing
- the fixed side 12 may be formed in parallel with the end side 11c. Although not shown in FIG. 4C, the peak portion 23 of the back foil piece 21 extends in parallel with the end side 11c. For this reason, the arrangement direction (adjacent direction, left-right direction in FIG. 4C) of the plurality of peak portions 23 is not orthogonal to the extending direction of the fixed side 12 and intersects.
- the top foil piece 11 and the fixed side 12 may be configured such that the direction in which the plurality of peak portions 23 are adjacent to each other and the extending direction of the fixed side 12 intersect.
- the fixed side 12 is formed so as to be parallel to the end side 11c on the downstream side in the rotation direction of the rotary shaft 1.
- the fixed side 12 has a rotation axis as it moves from the position near the inner peripheral edge of the top foil piece 11 toward the position near the outer peripheral edge (as it goes from the radially inner side to the outer side of the base plate 30).
- the top foil piece 11 is bent in the vicinity of the fixed side 12, so that a height substantially the same as the height of the peak portion 23 of the back foil piece 21 can be secured.
- the portion closer to the end side 11 c than the fixed side 12 is placed on the peak portion 23.
- the end side 11c (trading edge) is merely a free end supported on the peak portion 23 of the back foil piece 21 without being fixed to the base plate 30 or the like.
- the back foil piece 21 is arranged so that the trough portion 22 and the crest portion 23 are arranged in a direction orthogonal to the extending direction of the fixed side 12 of the top foil piece 11 as described above. Therefore, these valley portions 22 and peak portions 23 extend in parallel with the fixed side 12 and the end side 11 c of the top foil piece 11. Therefore, the top foil piece 11 is placed on the back foil piece 21 along the arrangement direction of the peak portions 23 (the direction in which the plurality of peak portions 23 are adjacent to each other and the direction perpendicular to the fixed side 12). As it goes from the vicinity of the fixed side 12 toward the end side 11c, the base plate 30 is arranged so as to be gradually inclined away from the inner surface (the surface facing the thrust collar 4). In a state where no bearing load is applied, the top foil piece 11 is arranged to be inclined at an initial inclination angle set by the peak portion 23 of the back foil piece 21.
- 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) ⁇ determined by the amount of increase in the height of the peak portion 23 of the back foil piece 21 as shown in FIG. 3C.
- the inclination angle of the present embodiment is an angle between the top foil piece 11 and the inner surface of the base plate 30. This inclination angle is equal to the angle between the top foil piece 11 and the supported surface of the thrust collar 4. Therefore, when the load increases, the crest portion 23 of the back foil piece 21 is pushed toward the base plate 30 and the whole is flattened, whereby the top foil piece 11 is also displaced toward the base plate 30, and the inclination angle ⁇ is initially set. It becomes smaller than the inclination angle.
- the top foil piece 11 has the fixed side 12 and the end side 11c arranged in parallel, and the back foil piece 21 that supports the top foil piece 11 has an arrangement direction of the peak portion 23 that is fixed to the fixed side 12. Orthogonal. For this reason, the end side 11c which is the free end of the top foil piece 11 is applied with a load on the back foil piece 21 via the top foil piece 11 by the rotation of the thrust collar 4 even in the initial inclination angle state, and the inclination angle ⁇ Even when becomes smaller, the height from the base plate 30 is always constant. That is, the height of the portion near the outer peripheral edge and the height of the portion near the inner peripheral edge in the end side 11c change in the same manner even when the inclination angle changes.
- the top foil piece 11 is displaced so as to move away from or approach the base plate 30 with the fixed side 12 as a fulcrum (rotation center). Even if it is turned, the downstream end side 11c has the same height near the outer peripheral edge and the inner peripheral edge. Therefore, even if the inclination angle changes, the downstream side edge 11 c that is the free end of the top foil piece 11 is always parallel to the thrust collar 4.
- the top foil piece 11 is a thin part formed thinner in the vicinity of the fixed side 12, that is, in the vicinity of the fixed side 12 on the downstream side in the rotation direction of the rotary shaft 1 as shown in FIG. 14.
- the thin 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 ⁇ m) of other portions constituting the top foil piece 11. Is formed.
- Such a thin portion 14 can be formed by, for example, etching.
- the thin portion 14 is formed on the surface of the top foil piece 11 near the back foil piece 21 so as not to affect the flow of the lubricating fluid.
- the thin portion 14 is formed so as not to contact the apex (ridge line) of the peak portion 23 closest to the fixed side 12 among the plurality of peak portions 23 in the back foil piece 21. ing. That is, the width of the thin portion 14 is set so as to be positioned between the fixed side 12 and the apex (ridge line) of the peak portion 23 positioned near the fixed side 12. As a result, the top foil piece 11 is placed on all the crests 23 except for the thin-walled portion 14 and is evenly supported by them, and the inclination angle ⁇ shown in FIG. 3C is maintained. .
- the thin portion 14 is formed, the portion closer to the end side 11c than the thin portion 14 can be displaced (rotated) more easily and smoothly with the fixed side 12 as a fulcrum (or with the thin portion 14 as a fulcrum). . 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.
- the thrust bearing 3A is provided on both sides of the thrust collar 4 as shown in FIG.
- the thrust bearings 3A are provided on both sides of the thrust collar 4 as shown in FIG.
- both thrust bearings 3A are installed close to the thrust collar 4 so that a large gap does not occur.
- the top foil pieces 11 (top foil 10) of both thrust bearings 3A are slightly pressed against the thrust collar 4 (supported surface of the thrust collar 4).
- the thin portion 14 is formed in the top foil piece 11 in this embodiment, the portion near the end 11c is easily displaced (easily bent). Therefore, the pressing force (reaction force) generated according to the pressing amount is reduced, and the starting torque is thereby reduced.
- an inclination angle larger than the optimum angle is previously attached to the top foil piece so that the inclination angle of the top foil piece becomes an optimum angle when the load increases. Accordingly, when the rotation is stopped, the top foil piece is in a state where the thrust collar 4 is sandwiched from both sides and is pressed (preloaded).
- the upstream side edge of the top foil piece is fixed to the base plate over its entire length, and since the thickness of the top foil piece is also constant, the pressing force (preload) to the thrust collar 4 is strong. The starting torque may increase.
- the length of the fixed side 12 is made shorter than the entire length of the upstream end side 11e, and the thin portion 14 is formed on the top foil piece 11, The generated pressing force (reaction force) is reduced, and the starting torque is reduced.
- the thrust collar 4 and the top foil piece 11 rub against each other and surround the wedge-shaped space (bearing gap) formed between them. Fluid is pushed in.
- a fluid lubricating film is formed between them.
- the top foil piece 11 top foil 10) is pressed against the back foil piece 21 (back foil 20) by the pressure of the fluid lubricating film, the top foil piece 11 is separated from the thrust collar 4, and the thrust collar 4 is separated from the top foil piece 11. Rotates without contact.
- the top foil piece 11 When a thrust load is applied, the top foil piece 11 is further pushed to the back foil piece 21, and the inclination angle ⁇ of the top foil piece 11 becomes small. At this time, the top foil piece 11 is displaced (bends) with the fixed side 12 on the upstream side in the rotation direction of the rotary shaft 1 as a fulcrum, but the downstream side edge 11 c serving as a free end is parallel to the fixed side 12. Therefore, even if the displacement of the top foil piece 11 advances, the parallel state with the thrust collar 4 of the edge 11c is maintained.
- the fixed shaft 12 fixed to the base plate 30 is moved from the position near the inner periphery to the position near the outer periphery of the top foil piece 11.
- the rising amount of the downstream side edge 11c is reduced between the portion near the outer peripheral edge and the inner peripheral edge. Can be the same for the part.
- the fixed side 12 is formed to extend from a position between both ends of the end side 11e on the upstream side in the rotation direction of the rotary shaft 1 in the top foil piece 11 to the outer peripheral edge. For this reason, the length of the fixed side 12 can be made shorter than the entire upstream end side 11e, thereby making it easy to displace (bend easily) the top foil piece 11 and reduce the starting torque. Further, even after the rotating shaft 1 starts rotating, the top foil piece 11 is easily and smoothly displaced, so that an optimum inclination angle (for example, about 0.1 °) can be easily obtained, and the load capacity of the bearing is improved. To do.
- the thin-walled portion 14 is formed in the vicinity of the top foil piece 11 on the downstream side in the rotation direction of the fixed side 12, the portion near the end side 11c is more easily and smoothly displaced when a load is applied. And thus the starting torque is reduced. Further, since the top foil piece 11 is easily and smoothly displaced even after the rotating shaft 1 starts to rotate, the optimum inclination angle is easily obtained, and the load capacity is improved.
- the top foil piece 11 can be compared with the conventional one without disturbing the movement of the top foil piece 11 to be displaced (bent).
- the plate thickness of 11 can be increased. Therefore, by thickening the plate
- 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. 5A to 5C, in the support region 31 of the base plate 30 in the inclined surface 32. And the height of the plurality of peak portions 23 of the back foil piece 21 are all the same.
- 5A is a plan view of the thrust bearing 3 partially in section
- FIG. 5B is a cross-sectional view taken along the line 5B-5B in FIG. 5A
- FIG. 5C is a plan view for explaining the shape of the bump foil piece. It is explanatory drawing which matched the side view.
- An inclined surface 32 is formed whose height increases as it goes to a position facing the end side 11c. That is, the inclined surface 32 is formed to be inclined in a direction orthogonal to the fixed side 12 and the end side 11c parallel to the fixed side 12, as shown in FIG. 5B.
- the back foil piece 21 is formed in a corrugated plate shape in which trough portions 22 in contact with the base plate 30 and crest portions 23 in contact with the top foil pieces 11 are alternately arranged as in the first embodiment. .
- the plurality of peak portions 23 are all formed at the same height.
- the valleys 22 and the peaks 23 are arranged in a direction orthogonal to the extending direction of the fixed side 12 of the top foil piece 11 as in the first embodiment. That is, the arrangement direction of the valley portion 22 and the mountain portion 23 is set to a direction orthogonal to the extending direction of the fixed side 12, and coincides with the inclination direction of the inclined surface 32.
- the peak portion 23 of the back 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, the heights of the vertices of the plurality of peak portions 23 are apparently the same as those in the first embodiment.
- the top foil piece 11 arranged on the back foil piece 21 is formed in the same manner as the first embodiment in the inclination angle ⁇ .
- the inclination angle ⁇ of the top foil piece 11 is determined by the inclination angle ⁇ of the inclined surface 32 as shown in FIG. 5C.
- the fixed side 12 is formed in parallel to the end side 11c, so that the top foil piece 11 moves away from the base plate 30 with the fixed side 12 as a fulcrum. Even if it is displaced so as to approach or approach, the rising amount (height) of the downstream side edge 11c can be made the same in the portion near the outer peripheral edge and the portion near the inner peripheral edge. Therefore, even if the thrust load changes during the rotation of the thrust collar 4, the downstream side edge 11c, which is the free end of the top foil piece 11, can always be parallel to the thrust collar 4, so that the bearing life is reduced. Reduction and seizure can be prevented.
- an inclined surface 32 is formed in each support region 31 of the base plate 30 so that the heights of the plurality of peak portions 23 of the back foil piece 21 are all the same, and the arrangement direction of the peak portions 23 is the inclination direction of the inclined surface 32.
- the height of the top foil piece 11 can be accurately changed along the inclined surface 32. That is, a predetermined inclination angle ⁇ can be given to the top foil piece 11.
- the back foil piece 21 may be produced at a constant height without changing the height of the peak portion 23, 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 quality variation is reduced, bearing performance (for example, bearing load capability) predicted at the time of design is easily obtained.
- the back foil 20 or the top foil 10 is composed of six back foil pieces 21 (bump foil pieces) or six top foil pieces 11, and accordingly, the support region 31 of the base plate 30 is also corresponding to this. Formation (setting).
- the number of the back foil pieces 21 (bump foil pieces) and the top foil pieces 11 may be 5 or less or 7 or more as long as it is plural.
- the number of support regions 31 is also the same as the number of back foil pieces 21 (bump foil pieces) and top foil pieces 11.
- a part of the support region is a flat surface.
- a part of the back foil piece 21 may be arranged on the inclined surface and the remaining part may be arranged on the flat surface.
- the flat surface may be formed on the upper side (close to the end side 11c, downstream) of the inclined surface, or may be formed on the lower side (close to the fixed side 12, upstream). Further, flat surfaces may be formed on both sides (upstream and downstream) of the inclined surface. It is also possible to adopt various forms other than the above-described embodiment, such as the shape of the top foil piece and the bump foil piece, the arrangement of the top foil piece and the bump foil piece on the support region, and the inclination direction of the inclined surface. is there.
- the present invention can be used for a thrust bearing that is disposed to face a thrust collar provided on a rotating shaft and supports the thrust collar.
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Abstract
Description
本願は、2013年1月28日に日本に出願された特願2013-013170号に基づき優先権を主張し、その内容をここに援用する。
スラストカラーとの接触を回避するには、トップフォイル片の自由端となる下流側端辺をスラストカラーに対して常に平行にしておくのが望ましい。しかし、トップフォイル片は、ベースプレートに固定された固定辺となる上流側端辺と自由端である下流側端辺との間隔が、ベースプレートの半径方向内側から外側に向かうに従い漸次拡がっている。このため、トップフォイル片の外周縁はその内周縁よりも長くなっている。ここで、軸受荷重の変化等を原因として、固定辺である上流側端辺を支点(回動中心)としてトップフォイル片がベースプレートから遠ざかるように又は近づくように変位(回動)すると、内周縁よりも長い外周縁は、内周縁よりも大きく変位する。よって、トップフォイル片の変位時において、自由端である下流側端辺の外周縁寄りの部分と、内周縁寄りの部分とのそれぞれの高さに違いが生じる場合がある。すなわち、トップフォイル片の外周縁の長さ(上流側端辺と下流側端辺との間の距離)が内周縁の長さ(上流側端辺と下流側端辺との間の距離)に比べて長くなるため、トップフォイル片が前記したように変位することにより、下流側端辺ではその外周縁寄りの部分の変位量が内周縁寄りの部分の変位量よりも大きくなる。
従って、トップフォイル片が固定辺を支点として変位すると、下流側端辺の外周縁寄りの部分又は内周縁寄りの部分がスラストカラーに接触し易くなる可能性がある。また、トップフォイル片の自由端となる下流側端辺がスラストカラーに対して非平行に配置されると、ベースプレートの半径方向において軸受隙間(特に軸受隙間が狭い側)が変化してしまい、適切な軸受の負荷能力を確保できなくなる可能性がある。
本発明者はこのような知見に基づきさらに鋭意検討を重ねた結果、本発明を完成させた。
本発明の第2の態様によれば、固定辺の長さが短くなることによって固定辺近傍の剛性が低減され、トップフォイル片が固定辺を支点として変位し易くなる。したがって、例えばスラストカラーが一対のトップフォイルによって挟み込まれているような場合に、始動トルクが低減する。また、回転軸が回転を開始した後も、トップフォイル片が容易にかつ円滑に変位するため、トップフォイル片の最適傾斜角が得られ易くなり、軸受の負荷能力が向上する。
本発明の第3の態様によれば、固定辺の長さが短くなることによって固定辺近傍の剛性が低減され、トップフォイル片が固定辺を支点として変位し易くなる。したがって、例えばスラストカラーが一対のトップフォイルによって挟み込まれているような場合に、始動トルクが低減する。また、回転軸が回転を開始した後も、トップフォイル片が容易にかつ円滑に変位するため、トップフォイル片の最適傾斜角が得られ易くなり、軸受の負荷能力が向上する。
本発明の第4の態様によれば、トップフォイル片の固定辺と回転軸の回転方向下流側の第2端辺とが平行に形成されているので、スラストカラーの回転時においてスラスト荷重が変化しトップフォイル片が固定辺を支点として変位しても、トップフォイル片の自由端となる下流側端辺がスラストカラー(スラストカラーの被支持面)に対して常に平行になる。
本発明の第5の態様によれば、固定辺の近傍に薄肉部が形成されているので、トップフォイル片における薄肉部よりも回転軸の回転方向下流側の部分がより容易にかつ円滑に変位できる。したがって、例えばスラストカラーが一対のトップフォイルによって挟み込まれているような場合に、始動トルクが低減する。また、回転軸が回転を開始した後も、トップフォイル片が容易にかつ円滑に変位するため、トップフォイル片の最適傾斜角が得られ易くなり、軸受の負荷能力が向上する。
本発明の第6の態様によれば、バンプフォイル片によってトップフォイル片を弾性的に支持することができる。
本発明の第7の態様によれば、この傾斜面上にバックフォイル片を介してトップフォイル片を配設することにより、トップフォイル片の高さを傾斜面に沿って精度よく変化させることができる。また、その際にバックフォイル片については、その高さを変化させることなく一定の高さに作製すればよく、したがってその加工コストを抑えることができる。
本発明の第8の態様によれば、バンプフォイル片によってトップフォイル片を弾性的に支持することができる。
本発明の第9の態様によれば、トップフォイル片に発生する流体潤滑膜の圧力が軸受隙間の狭い側、すなわち回転軸の回転方向下流側で高くなるようにするべく、軸受隙間の回転方向下流側の部分を高い剛性で支持することができ、これによって軸受の負荷能力を高めることができる。
図1は、本発明のスラスト軸受が適用されるターボ機械の一例を模式的に示す側面図であり、図1中符号1は回転軸、符号2は回転軸の先端部に設けられたインペラ、符号3は本発明に係るスラスト軸受である。
また、インペラ2は静止側となるハウジング5内に配置されており、インペラ2とハウジング5との間にチップクリアランス6が形成されている。
また、回転軸1には、スラストカラー4より中央寄りの部分に、ラジアル軸受7が設けられている。
本実施形態では、一対のスラスト軸受3A、3Aの、それぞれのベースプレート30、30間に、二点鎖線で示す円筒状の軸受スペーサ40が挟持されており、ベースプレート30、30は締結ボルト41によって軸受スペーサ40を介して連結されている。また、一方のベースプレート30の外面が、締結ボルト41によってハウジング5に固定されている。したがって一対のスラスト軸受3A、3Aは、スラストカラー4を挟んだ状態で締結ボルト41によってハウジング5に固定されている。
図3A~3Cに示すようにバックフォイル20は、ベースプレート30の周方向に配列された6枚のバックフォイル片21を有して形成されている。これらバックフォイル片21は、ベースプレート30の複数の支持領域31上にそれぞれ配置され、これによってベースプレート30の周方向に配列されている。また、これらバックフォイル片21は、後述するトップフォイル片11より平面視で僅かに小さく形成され、したがって図3Aに示すようにベースプレート30上にてスラストカラー4に向けて露出することなく、トップフォイル片11に覆われている。
また、バックフォイル片21は、回転軸1の回転方向下流側の端辺21aが、後述するトップフォイル片11における回転軸1の回転方向下流側の端辺11c(第2端辺)と平面視した状態でほぼ一致する位置に配置されている。バックフォイル片21は、この端辺21aとなる谷部22の形成方向に沿って、ベースプレート30にスポット溶接(点付溶接)され、固定されている。
なお、ベースプレート30への端辺21aの固定については、スポット溶接以外にも、例えばネジ止めなどによって行うことができる。
トップフォイル片11における回転軸1(スラストカラー4)の回転方向上流側の端辺11e(第1端辺)は、本実施形態では、トップフォイル片11の内周縁から外周縁に向かって延びる内側辺11aと、内側辺11aの上記外周縁寄りの端部からトップフォイル片11の外周縁(半径方向外側の縁)にまで延びる外側辺11bとを有して形成されている。このような端辺11eのうちの外側辺11bに、ベースプレート30に固定されている固定辺12が設けられている。
例えば、図4Aに示すように矢印で示す回転軸1(スラストカラー4)の回転方向の上流側でかつ外周縁寄りの部分を切り欠くことなく、略台形形状(扇形からその頂点を含む部分を切り取った形状)にトップフォイル片11を形成した場合に、図3Aに示した固定辺12と対応する位置のみをスポット溶接等によってベースプレート30に固定し、この固定箇所を固定辺12(固定部13)としてもよい。
この場合に、固定辺12は、トップフォイル片11における回転軸1の回転方向上流側の端辺11e(第1端辺)の両端の間の位置からトップフォイル片11の外周縁まで延びて形成され、回転軸1やベースプレート30の半径方向に延びる直線(回転方向上流側の端辺11e)に対して傾斜して形成されている。
なお、この場合、固定辺12より回転軸1の回転方向上流側でかつ外周縁寄りに位置する部位11dは、負荷能力の点ではほとんど機能しない。しかしながら、この部位11dを切り欠く加工を省略できるため、図3Aに示したトップフォイル片11に比べてその加工を容易にでき、製作コストを低減できる。
図4Cでは図示しないが、バックフォイル片21の山部23は、端辺11cと平行に延びている。このため、複数の山部23の配列方向(隣り合う方向、図4Cの左右方向)は、固定辺12の延在方向と直交しておらず、交差している。このように、複数の山部23の隣り合う方向と固定辺12の延在方向とが交差するように、トップフォイル片11や固定辺12が構成されていてもよい。
一方、端辺11c(トレーディングエッジ)は、ベースプレート30等に固定されることなく単にバックフォイル片21の山部23上に支持された自由端となっている。
本実施形態では、図2に示したようにスラスト軸受3Aをスラストカラー4の両側に設けている。このようにスラストカラー4の両側にスラスト軸受3Aを設けることにより、スラスト方向におけるスラストカラー4(回転軸1)の移動量を極力抑えることができる。すなわち、スラスト移動量を小さくすることにより、図1に示したチップクリアランス6を狭くした場合でもインペラ2等のハウジング5への接触を防止でき、チップクリアランス6を狭くすることでターボ機械等の流体性能を向上することができる。
これに対して本実施形態では、前記したように固定辺12の長さを上流側の端辺11eの全体の長さより短くし、さらにトップフォイル片11に薄肉部14を形成しているため、生じる押し付け力(反力)が低減され、始動トルクが小さくなる。
第2実施形態のスラスト軸受3B(3)が第1実施形態のスラスト軸受3A(3)と主に異なるところは、図5A~5Cに示すように、ベースプレート30の前記支持領域31に傾斜面32を形成した点と、バックフォイル片21の複数の山部23の高さを、全て同一にした点である。なお、図5Aは一部を断面視したスラスト軸受3の平面図、図5Bは図5Aの5B-5B線矢視断面図、図5Cはバンプフォイル片の形状を説明するためにその平面図と側面図を対応させた説明図である。
すなわち、傾斜面32を、図5Bに示すように固定辺12、およびこれに平行な端辺11cに対して直交する方向に傾斜させて形成している。
例えば、前記実施形態ではバックフォイル20又はトップフォイル10を6つのバックフォイル片21(バンプフォイル片)又は6つのトップフォイル片11で各々構成し、したがってベースプレート30の支持領域31もこれに合わせて6つ形成(設定)した。しかし、バックフォイル片21(バンプフォイル片)やトップフォイル片11は、複数であれば5つ以下でも7つ以上であってもよい。その場合、支持領域31の数も、バックフォイル片21(バンプフォイル片)やトップフォイル片11の数と同じになる。
また、トップフォイル片やバンプフォイル片の形状、支持領域上へのトップフォイル片やバンプフォイル片の配置、傾斜面の傾斜方向など、前記実施形態以外にも種々の形態を採用することが可能である。
3,3A,3B スラスト軸受
4 スラストカラー
10 トップフォイル
11 トップフォイル片
11a 内側辺
11b 外側辺
11c 端辺(第2端辺)
11e 端辺(第1端辺)
12 固定辺
13 固定部
14 薄肉部
20 バックフォイル
21 バックフォイル片
21a 端辺
22 谷部
23 山部
30 ベースプレート
31 支持領域
32 傾斜面
Claims (9)
- 回転軸に設けられたスラストカラーに対向して配置されるスラスト軸受であって、
前記スラストカラーに対向して配置されるトップフォイルと、
前記トップフォイルの、前記スラストカラーに対向する面と反対側の面に対向して配置されて、前記トップフォイルを支持するバックフォイルと、
前記バックフォイルの、前記トップフォイル寄りの側と反対の側に配置されて、前記バックフォイルを支持する円環状のベースプレートと、を備え、
前記バックフォイルは、前記ベースプレートの周方向に配列された複数のバックフォイル片を有し、
前記トップフォイルは、前記複数のバックフォイル片の上にそれぞれ配設された複数のトップフォイル片を有し、
前記トップフォイル片の、前記回転軸の回転方向上流側の部分には、前記ベースプレートに固定される固定部が形成され、
前記固定部の、前記回転軸の回転方向下流側に位置する固定辺は、前記ベースプレートの半径方向内側から外側に向かうに従い前記回転軸の回転方向下流側に近づくように直線状に延びて、前記半径方向に延びる直線に対して傾斜しているスラスト軸受。 - 前記固定辺は、前記トップフォイル片における前記回転軸の回転方向上流側に位置する第1端辺の両端の間の位置から、前記トップフォイル片の外周縁まで延びて形成されている請求項1に記載のスラスト軸受。
- 前記トップフォイル片における前記回転軸の回転方向上流側の第1端辺は、前記トップフォイル片の内周縁から外周縁に向かって延びる内側辺と、該内側辺の前記外周縁寄りの端部から前記外周縁にまで延びる外側辺とを有し、
前記外側辺に、前記固定辺が設けられている請求項1に記載のスラスト軸受。 - 前記固定辺は、前記トップフォイル片における前記回転軸の回転方向下流側の第2端辺に対して平行に形成されている請求項2又は3に記載のスラスト軸受。
- 前記トップフォイル片は、前記固定辺における前記回転軸の回転方向下流側の近傍に、前記トップフォイルの他の部分に比べて薄肉に形成された薄肉部を有している請求項1~4のいずれか一項に記載のスラスト軸受。
- 前記バックフォイル片は、複数の山部と複数の谷部とを交互に形成した波板状に形成されるとともに、前記複数の山部の隣り合う方向が前記固定辺の延在方向と交差するように配置され、前記複数の山部の高さが、前記固定辺寄りに位置する前記バックフォイル片の端部から前記回転軸の回転方向下流側に向かうに従い漸次高くなっている請求項1~5のいずれか一項に記載のスラスト軸受。
- 前記ベースプレートには、前記複数のバックフォイル片をそれぞれ支持する複数の支持領域が設けられ、各支持領域に、前記固定辺が設けられた位置から前記回転軸の回転方向下流側に向かうに従い漸次高さが増加する傾斜面が形成されている請求項1~5のいずれか一項に記載のスラスト軸受。
- 前記バックフォイル片は、複数の山部と複数の谷部とを交互に形成した波板状に形成されるとともに、前記複数の山部の隣り合う方向が前記傾斜面の傾斜方向に一致するように配置されている請求項7に記載のスラスト軸受。
- 前記バンプフォイル片は、前記回転軸の回転方向下流側の端辺で前記ベースプレートに固定されている請求項6又は8に記載のスラスト軸受。
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CA2899407A CA2899407C (en) | 2013-01-28 | 2014-01-24 | Thrust bearing |
CN201480006084.8A CN104937291B (zh) | 2013-01-28 | 2014-01-24 | 推力轴承 |
KR1020177009206A KR101803025B1 (ko) | 2013-01-28 | 2014-01-24 | 스러스트 베어링 |
EP14743151.4A EP2949953B1 (en) | 2013-01-28 | 2014-01-24 | Thrust bearing |
KR1020157020843A KR101727104B1 (ko) | 2013-01-28 | 2014-01-24 | 스러스트 베어링 |
US14/809,933 US9677609B2 (en) | 2013-01-28 | 2015-07-27 | Thrust bearing |
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JP7139800B2 (ja) | 2018-09-04 | 2022-09-21 | 株式会社Ihi | スラストフォイル軸受 |
JP7192320B2 (ja) | 2018-09-04 | 2022-12-20 | 株式会社Ihi | スラストフォイル軸受 |
WO2020137513A1 (ja) * | 2018-12-25 | 2020-07-02 | 株式会社Ihi | スラストフォイル軸受、スラストフォイル軸受のベースプレートの製造方法 |
EP3928886B1 (en) * | 2019-02-22 | 2023-11-22 | IHI Corporation | Thrust foil bearing, and method for manufacturing base plate of thrust foil bearing |
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JP6221244B2 (ja) | 2017-11-01 |
CA2899407C (en) | 2018-01-30 |
CN104937291A (zh) | 2015-09-23 |
US9677609B2 (en) | 2017-06-13 |
EP2949953A1 (en) | 2015-12-02 |
KR20170041284A (ko) | 2017-04-14 |
CN104937291B (zh) | 2018-09-18 |
CA2899407A1 (en) | 2014-07-31 |
US20150330443A1 (en) | 2015-11-19 |
EP2949953A4 (en) | 2016-09-21 |
JP2014145388A (ja) | 2014-08-14 |
CA2968870C (en) | 2018-09-18 |
KR101803025B1 (ko) | 2017-11-29 |
CA2968870A1 (en) | 2014-07-31 |
EP2949953B1 (en) | 2017-12-27 |
KR20150102120A (ko) | 2015-09-04 |
KR101727104B1 (ko) | 2017-04-14 |
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