JP2015124870A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve vibration damping effect to a rotating shaft by making the rotating shaft easily float by simple and inexpensive means, in a bearing device of the rotating shaft having a squeeze film damper function.SOLUTION: A bearing chamber cs filled with a lubricant o is formed around a turbine rotor shaft 20. A cylindrical floating bush 32A surrounding the turbine rotor shaft 20 is disposed in the bearing chamber cs. Squeeze dampers are formed by oil films formed between the turbine rotor shaft 20 and the floating bush 32A and between the floating bush 32A and a bearing housing 13. A detent regulation device 33 is composed of a recessed portion 34 formed on the bearing housing 13 and a projecting portion 36 projecting from the floating bush 32A. The projecting portion 36 is slidably fitted inside of the recessed portion 34, and the recessed portion 34 is inclined with respect to the vertical direction.

Description

  The present invention relates to a bearing device that promotes floating of a floating ring formed with a squeeze film damper and enables stable support of a rotating shaft system.

In recent turbo machines such as turbochargers, large capacity and high speed are required, and as the capacity and high speed are increased, the rotating shaft system tends to cause unstable vibration. As a countermeasure, it is effective to use a tilting pad bearing, but it is expensive.
Therefore, by using a bearing having a squeeze film damper function, cost reduction and compactness are achieved while suppressing unstable vibration. This bearing device has a rotating shaft system in which a bearing chamber filled with lubricating oil is formed around the rotating shaft, a floating bush is disposed in the bearing chamber, and the lubricating oil is interposed between the rotating shaft and the floating bush. This makes it possible to suppress vibrations.

  Patent Document 1 discloses a bearing device having a squeeze film damper function. Patent Document 2 discloses a bearing device in which a bearing chamber surrounding a rotating shaft is filled with lubricating oil and a floating bush is provided around the rotating shaft. Patent Document 3 discloses a bearing device in which a cylindrical floating metal is interposed between a rotating shaft and a bearing housing.

  In a small exhaust turbine supercharger, the rotational speed of the rotating shaft reaches several hundred thousand rpm, so the floating bush or metal is rotated to reduce the relative speed difference between the bearing housing that does not rotate and the rotating shaft. Yes. On the other hand, large rotating machines, such as marine exhaust turbine superchargers, do not rotate as fast as small superchargers. Noise generation is suppressed.

Patent Document 1 and Patent Document 3 disclose means for stopping rotation by bridging a detent pin between a bearing housing and a floating bush or a floating metal. Further, Patent Document 1 discloses a means for constructing a centering spring between the floating bush and the non-rotating portion and holding the floating bush in a concentric position with the bearing housing.
Patent Document 4 discloses means for suppressing the self-excited vibration of the bearing housing by making the inner surface of the bearing housing forming the bearing chamber a curved surface such as a corrugated curved surface.

Japanese Patent Laid-Open No. 05-044722 JP 2002-213450 A Japanese Patent Laid-Open No. 2002-070570 JP 11-336744 A

When the centering spring is not provided, the rotating shaft and the floating bush are lowered downward in the bearing chamber while the rotating shaft is stopped. When the shaft rotates, the lubricating oil is dragged from a wide space into a narrow gap, oil film pressure is generated, and the shaft holding pressure is increased. This is called the wedge effect, and that space is called the wedge space.
After the rotating machine is started, the lubricating oil enters the wedge space formed between the rotating shaft and the floating bush and between the floating bush and the inner surface of the bearing housing, and the oil film pressure is generated in the wedge space. Ascend to the center of the chamber. The rotating shaft and the floating bush are lifted to some extent, and if no lubricating oil is interposed between these members, the vibration damping effect cannot be obtained.
On the other hand, the floating bush lowering prevention means using the centering spring described above is contrary to the simplification of the structure and the cost reduction.

  Since the detent pins disclosed in Patent Documents 1 and 3 are arranged in the vertical direction on the top of the floating bush, the floating bush and the rotary shaft are allowed to move in the vertical direction. However, the lubricating oil pressure applied to the rotating shaft does not necessarily act in the direction perpendicular to the rotating shaft. Since the non-rotating pin does not allow the floating bush and the rotating shaft to move from the vertical direction to the inclined direction, when the lubricating oil pressure acts on the rotating shaft in a direction inclined with respect to the vertical direction, the floating bush and the rotating shaft are smooth. Does not surface. Therefore, there is a problem that the vibration damping effect is not satisfactorily exhibited with respect to the rotating shaft at the time of starting or during low rotation.

  In view of the problems of the prior art, the present invention is a rotary shaft bearing device having a squeeze film damper function, which makes it easy to float the rotary shaft with a simple and low-cost means, thereby reducing the vibration damping effect on the rotary shaft. The purpose is to increase.

  A bearing device according to an embodiment of the present invention includes a bearing housing including a bearing chamber filled with lubricating oil, a floating bush disposed in the bearing chamber, and a rotating shaft at least partially disposed in the floating bush. A convex portion provided on one of the floating bush and the bearing housing, and a concave portion provided on the other of the floating bush and the bearing housing and reciprocally receiving the convex portion in a radial direction inclined with respect to the vertical direction. Yes.

  In the above-described configuration, the concave portion receives the convex portion so as to be able to reciprocate in the radial direction inclined from the vertical direction, so that even if lubricating oil pressure is applied to the rotational shaft in a direction inclined from the vertical direction, the rotational shaft is smoothly floated. be able to. Therefore, the floating bush can follow the rotating shaft and float smoothly. Therefore, the vibration damping effect with respect to the rotating shaft is promptly exhibited at the time of starting or during low rotation, and the rotating shaft system can be stably supported. Moreover, this can be achieved simply and at low cost.

  In one embodiment of the present invention, the convex portion is constituted by a detent pin provided on the floating bush, and the concave portion is constituted by a guide groove provided on the bearing housing. Accordingly, the configuration of the convex portion and the concave portion can be simplified and reduced in cost, and the rotating shaft can be smoothly lifted even when lubricating oil pressure is applied to the rotating shaft from the vertical direction to the inclined direction.

  In one embodiment of the present invention, the guide groove extends with an inclination in a direction opposite to the rotation direction of the rotation axis with respect to the vertical direction, or inclines in the same direction as the rotation direction of the rotation axis with respect to the vertical direction. It extends.

In one embodiment of the present invention, at least a part of the rotating shaft (for example, a journal portion formed on the rotating shaft) and the floating bush are wedge spaces formed between at least a part of the rotating shaft and the floating bush. The squeeze force is applied to at least a part of the rotating shaft by the lubricating oil existing in the above, and the guide groove is disposed so as to extend along the direction in which the squeeze force is applied.
Thus, since the direction of action of the squeeze force acting on the rotating shaft and the arrangement direction of the guide groove coincide with each other, the rotating shaft and the floating bush are smoothly lifted.

In one embodiment of the present invention, the inner surface of the floating bush can be configured to include a plurality of arcs in a cross-sectional view.
This makes it possible to form an end portion of the pressure distribution of the lubricating oil that generates a squeeze force at the boundaries of a plurality of arcs. Therefore, the squeeze force acting on the rotation shaft can be applied to the rotation shaft in a desired direction. Therefore, it is possible to select a desired position where the guide groove is easily arranged.

  In one embodiment of the present invention, the inner surface of the floating bush may include a plurality of arcs having relatively different curvature center positions in a cross-sectional view. As a result, the end portion of the pressure distribution of the lubricating oil can be formed at the boundaries of the plurality of arcs, so that the squeeze force acting on the rotating shaft can be applied in a desired direction and the guide groove can be selected at a desired position.

  In one embodiment of the present invention, the inner surface of the floating bush may include two half cylinders having relatively different curvature center positions and at least one stepped surface connecting the ends of the two half cylinders. it can. As a result, the end portion of the pressure distribution of the lubricating oil can be formed on the stepped surface, so that the squeeze force acting on the rotating shaft can be applied in a desired direction, and the guide groove can be easily arranged at a desired position.

  In an embodiment of the present invention, the plurality of arcs included in the inner surface of the floating bush may have the same length. As a result, the squeeze force acting on the rotating shaft can be applied in a desired direction, and the guide groove can be arranged at a desired position where it can be easily arranged.

In one embodiment of the present invention, the outer surface of the floating bush and the inner surface of the bearing housing are two between the position of the detent pin and the position opposite to the position of the detent pin in the circumferential direction of the floating bush. The two regions of at least one of the outer surface of the floating bush and the inner surface of the bearing housing may have different shapes at least partially.
As described above, since the two regions are formed differently, it is possible to make a difference in the force applied from the bearing housing to the floating bush via the lubricating oil. For this reason, it is possible to generate a moment that acts in the direction in which the floating bush floats with the rotation stopper pin as a base point. Therefore, the floating bush can be floated more easily.

In one embodiment of the present invention, the outer surface of the floating bush may have a concavo-convex portion in at least a part of a region including the apex in the vertical direction among the two regions.
As a result, a moment acting in the direction in which the floating bush is floated with the rotation stopper pin as a base point is generated, and the floating bush can be floated more easily.

In one embodiment of the present invention, the inner surface of the bearing housing has an upper arc that forms one region including the apex in the vertical direction among the two regions, and a lower arc that forms the other region in the cross-sectional view. And the radius of curvature of the upper arc can be greater than the radius of curvature of the lower arc.
As a result, a moment acting in the direction in which the floating bush is floated with the rotation stopper pin as a base point is generated, and the floating bush can be floated more easily.

According to an embodiment of the present invention, at least a part of the rotating shaft and the floating bush are squeezed into at least a part of the rotating shaft by lubricating oil existing in a wedge space formed between at least a part of the rotating shaft and the floating bush. And the shape of at least one of the outer surface of the floating bush and the inner surface of the bearing housing is such that the force that reduces the resultant force of gravity and squeeze force acting on at least a part of the rotating shaft is reduced. It is formed so as to act on the floating bush from the inner surface.
As a result, a moment is generated that acts in the direction in which the floating bush is floated with the non-rotating pin as a base point to reduce the resultant force, so that the floating bush can be floated more easily.

  According to one embodiment of the present invention, the rotary shaft and the floating bush can be easily lifted in the bearing chamber when the rotary shaft system is started or when the rotary shaft system is rotated at low speed by simple and low-cost means. The effect can be enhanced and the rotating shaft system can be stably supported.

1 is a longitudinal sectional view of an exhaust turbine supercharger to which a bearing device of the present invention is applied. It is a partially expanded sectional view of FIG. It is a cross-sectional view of the bearing device according to the first embodiment of the present invention. It is a cross-sectional view of a bearing device according to a second embodiment of the present invention. It is a cross-sectional view of a bearing device according to a third embodiment of the present invention. It is a cross-sectional view of a bearing device according to a fourth embodiment of the present invention. It is a cross-sectional view of a bearing device according to a fifth embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a marine exhaust turbine supercharger provided with the bearing device of the present embodiment. In FIG. 1, an exhaust turbine supercharger 10 includes a turbine housing 11, a compressor housing 12 made of an aluminum alloy, and a bearing housing 13. Reference numeral 11 a denotes an outlet passage for the exhaust gas e, reference numeral 11 b denotes an inlet passage for the exhaust gas e, reference numeral 15 denotes an axial-flow turbine blade, and reference numeral 16 denotes a turbine nozzle provided at the inlet of the turbine blade 15. The turbine blade 15 is rotationally driven by the axial exhaust gas flow statically expanded by the turbine nozzle 16.

A compressor impeller 17 and a diffuser 18 are accommodated in the compressor housing 12. An air inlet (working fluid inlet) 12 a is formed in the compressor housing 12, and air a is supplied from the air inlet 12 a to the compressor impeller 17. The air a pressurized (compressed) by the compressor impeller 17 passes through the diffuser 18 and the outlet scroll 19 and is supplied to a large diesel engine (not shown) such as a ship.
In FIG. 1, reference numeral 20 is a turbine rotor shaft provided with a disk 21 and supported by two radial bearing devices 30A of the present invention, reference numeral 22 is a thrust bearing that receives axial axial thrust, and reference numeral 14 is an exhaust. It is a rotating shaft of the turbine supercharger 10.

During the operation of the exhaust turbine supercharger 10 having such a configuration, the exhaust gas e from the large diesel engine passes through the inlet passage 11b and is turbine blades by the axial exhaust gas flow statically expanded by the turbine nozzle 16. 15 is rotationally driven. And the exhaust gas e which driven the turbine blade 15 is discharged | emitted outside from the exit channel | path 11a.
The rotation of the turbine blade 15 rotates the compressor impeller 17 through the turbine rotor shaft 20 and sucks air a from the air inlet 12a. The sucked air a is pressurized by the compressor impeller 17, passes through the diffuser 18 and the outlet scroll 19, and is supplied to the large diesel engine.

  Further, at least one ejection hole 23 penetrating in the plate thickness direction is formed in the compressor housing 12 facing the outer periphery of the bottom surface (end surface on the large diameter side) of the compressor impeller 17. One end of a cooling air supply pipe 24 is connected to the ejection hole 23.

  As shown in FIG. 2, the inner surface of the bearing housing 13 has a perfect circle shape, and a bearing chamber cs is formed so as to surround the turbine rotor shaft 20. A lubricating oil passage 26 is formed in the bearing housing 13, and the lubricating oil passage 26 communicates with the bearing chamber cs. Lubricating oil o is supplied from a lubricating oil supply source (not shown) to the bearing chamber cs through the lubricating oil passage 26, and the bearing chamber cs is filled with the lubricating oil o.

The bearing device 30A according to the present embodiment includes a cylindrical floating bush 32A disposed so as to surround the turbine rotor shaft 20 in the bearing chamber cs, a guide groove 34 formed in an upper region of the bearing housing 13, and a floating bush. It is composed of a cylindrical anti-rotation pin 36 projecting from one end face of 32A in the axial direction of the floating bush 32A. A guide groove 34 is formed in the bearing housing 13, and a detent pin 36 is inserted into the guide groove 34. The guide groove 34 and the anti-rotation pin 36 constitute the anti-rotation restricting device 33.
Instead of the guide groove 34, a guide hole may be formed. The guide hole may be formed in the floating bush 32 </ b> A. In this case, the detent pin 36 may be provided in the bearing housing 13.

As shown in FIG. 3, the bearing chamber cs is filled with the lubricating oil o, the guide groove 34 is disposed from the bearing housing 13 toward the turbine rotor shaft 20, and the anti-rotation pin 32 slides inside the guide groove 34. The guide groove 34 is loosely fitted as possible. In the figure, the arrow b indicates the rotational direction of the rotary shaft 14, the X axis indicates the horizontal direction, and the Y axis indicates the vertical direction. The guide groove 34 is schematically shown for easy understanding.
When the turbine rotor shaft 20 rotates in the direction of arrow b, the pressure distribution P is formed by the wedge effect of the lubricating oil film interposed in the wedge space ws formed between the turbine rotor shaft 20 and the floating bush 32A. In the figure, an arrow F1 indicates the squeeze force that the turbine rotor shaft 20 receives from the lubricating oil film due to the pressure distribution P.

The guide groove 34 extends along one direction inclined with respect to the vertical direction. More specifically, the guide groove 34 is disposed in the direction in which the squeeze force F1 due to the wedge effect acts, and is disposed along the squeeze force F1. In the figure, F2 is the force that the floating bush 32A receives from the lubricating oil film.
In such a configuration, when the operation of the exhaust turbine supercharger 10 is started, the turbine rotor shaft 20 receives the squeeze force F1 and floats in the direction in which the squeeze force F1 acts. The floating bush 32A also floats in the same direction as the turbine rotor shaft 20 due to the force received from the inner surface of the bearing housing 13 through the lubricating oil as a reaction force against the force F2.
Preferably, the circumferential position of the guide groove 34 is set 180 ° opposite to the position where the maximum squeeze force F1 is generated by the wedge effect.

According to this embodiment, the guide groove 34 is provided at a position opposite to the squeeze force F1 received by the turbine rotor shaft 20 by the lubricating oil film interposed in the wedge space ws, and the guide groove 34 is provided in a direction opposite to the squeeze force F1. Thus, the floating bush 32 </ b> A can easily float in the same direction as the turbine rotor shaft 20 as the turbine rotor shaft 20 floats.
Therefore, when the exhaust turbine supercharger 10 is started or when the rotating shaft 14 is started or when the rotating shaft 14 is rotating at a low speed, the vibration damping effect on the rotating shaft system is rapidly increased, so that unstable vibration can be effectively prevented. In addition, this can be realized with a simple and low-cost configuration.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. In the bearing device 30B according to the present embodiment, the inner surface shape of the floating bush 32B is different from that of the floating bush 32A of the first embodiment. The shape of the inner surface of the floating bush 32B is formed by a semicircular arc 38a that forms the upper half semicircular region of the bearing housing inner surface and a semicircular arc 38b that forms the lower half semicircular region. The semicircular arcs 38a and 38b are located at positions shifted from each other in the radial direction (X-axis direction) of the turbine rotor shaft 20, and flat step surfaces 40a and 40b are formed at the boundary between them. Other configurations are the same as those of the first embodiment.

  As shown in FIG. 4, in this embodiment, the start end of the pressure distribution P by the lubricating oil film formed between the turbine rotor shaft 20 and the floating bush 32B is formed on the step surface 40b. Therefore, the squeeze force F1 acts on the turbine rotor shaft 20 in the upper left direction. Accordingly, the guide groove 34 is provided at a position (the upper left region of the bearing housing 13) facing the squeeze force F1 and arranged in a direction facing the squeeze force F1.

Thus, by forming the inner surface shape of the floating bush 32B, the direction in which the squeeze force F1 acts can be directed to a desired direction, and the guide groove 34 is disposed at a set position where the formation above the journal portion is easy. it can. Therefore, the guide groove 34 can be easily formed, and the guide groove 34 can be disposed above the turbine rotor shaft 20, so that the floating bush 32B can easily float. Further, since the pressure at the end of the pressure distribution P can be increased by the dimension in the X-axis direction of the stepped surface 40b, the pressure value of the pressure distribution P can be increased accordingly.
As a result, the vibration damping effect by the lubricating oil film on the rotating shaft system can be enhanced at the time of starting or at a low rotation, and the occurrence of unstable vibration can be effectively prevented.

(Embodiment 3)
Next, a third embodiment of the present invention will be described with reference to FIG. The bearing device 30C according to the present embodiment is formed by three arcs 42a, 42b, and 42c having a radius of curvature larger than the inner diameter of the circular shape when the inner surface shape of the floating bush 32C is circular. The arcs intersect at intersections B, C, and D, respectively, have different centers of curvature, and form a Reuleaux triangle.

  In the present embodiment, the start end of the pressure distribution P of the lubricating oil film in the wedge space ws formed between the turbine rotor shaft 20 and the floating bush 32B coincides with the intersection D. Therefore, as shown in FIG. 5, the squeeze force F1 acts on the turbine rotor shaft 20 in the upper right direction. Accordingly, the guide 34 is provided at a position (the upper right region of the bearing housing 13) facing the squeeze force F1, and the guide groove 34 is arranged in a direction facing the squeeze force F1. Other configurations are the same as those of the second embodiment.

  In this way, by forming the inner shape of the floating bush 32C, the guide groove 34 can be disposed at a set position where the formation above the journal portion is easy. Therefore, the guide groove 34 can be easily formed, and the guide groove 34 can be disposed above the turbine rotor shaft 20, so that the floating bush 32 </ b> C is likely to float, and the exhaust turbine supercharger 10 is started or is rotated at a low speed. At this time, the vibration damping effect of the lubricating oil film on the rotating shaft system can be enhanced, and the occurrence of unstable vibration can be effectively prevented. Therefore, the occurrence of unstable vibration can be effectively prevented.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described with reference to FIG. In the bearing device 30 </ b> D according to the present embodiment, the inner shape of the floating bush 32 </ b> D is configured to be circular like the floating bush 32 </ b> A of the first embodiment. Therefore, the pressure distribution P due to the lubricating oil film formed between the turbine rotor shaft 20 and the floating bush 32D is generated at the same position as the pressure distribution P formed in the first embodiment and has the same pressure shape.
Therefore, as shown in FIG. 6, the squeeze force F1 acts on the turbine rotor shaft 20 in the same direction as in the first embodiment, so that the guide groove 34 is the same region as the guide groove 34 and the bearing housing 13 in the first embodiment. They are installed in the same direction.

A squeeze force F <b> 1 and gravity G are added to the turbine rotor shaft 20. That is, the resultant force Fr of the squeeze force F1 and the gravity G is added to the rotating shaft 14.
On the other hand, the floating bush 32D receives force from the inner surface of the surrounding bearing housing 13 via the lubricating oil. When the outer peripheral surface of the floating bush 32D has a perfect circle shape like the floating bush 32A of the first embodiment, the floating bush 32D receives a uniform force from the bearing housing 13 in the circumferential direction.

  On the other hand, as shown in FIG. 6, the floating bush 32D is divided into two regions of an upper arc h1 and a lower arc h2 each including the vertical apex, with the arrangement position of the guide 34 as a boundary. On the outer peripheral surface of the floating bush 32D to which it belongs, a plurality of concave grooves 44 arranged in the axial direction of the floating bush 32D are formed at predetermined intervals. The concave groove 44 forms an uneven portion on the outer peripheral surface of the floating bush 32D.

  Therefore, the force F3 that the floating bush 32D is applied from the bearing housing 13 through the lubricating oil film in the upper arc h1 is smaller than the force F4 that the floating bush 32D receives from the bearing housing 13 through the lubricating oil film in the lower arc h2. Therefore, a moment M with the rotation stop pin 36 as a base point is added to the floating bush 32D. The moment M is a moment that acts in the direction in which the floating bush 32D is lifted, and is a moment that is not hindered by the guide groove 34 because it is based on the detent pin 36 that can slide the guide groove 34.

According to the present embodiment, since the moment M further acts on the floating bush 32D in addition to the squeeze force F1, the floating bush 32D can be more easily floated inside the bearing housing 13. Therefore, during operation of the exhaust turbine supercharger 10, the vibration damping effect on the rotating shaft system can be further enhanced, and the rotating shaft system can be stably supported.
If the force F4−the force F3> the resultant force Fr is satisfied, the floating bush 32D can be further lifted.
Further, instead of the concave groove 44, a concave groove, a dimple (concave part), or a bump (convex part) arranged in the circumferential direction of the floating bush 32D may be provided on the outer peripheral surface of the floating bush 32D.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described with reference to FIG. In the bearing device 30E according to the present embodiment, a floating bush having the same configuration as that of the floating bush 32A in the first embodiment is used. Further, the inner surface of the bearing housing 13 is divided into an upper arc h3 and a lower arc h4, respectively, with the guide groove 34 as a boundary, and the inner diameter of the upper arc h3 is larger than the inner diameter of the lower arc h4. Other configurations are the same as those of the first embodiment.

With the above configuration, the squeeze force F1 applied to the turbine rotor shaft 20 acts in the same direction as in the first embodiment, so that the guide groove 34 is provided at the same position and in the same direction as the first embodiment and the bearing housing 13. Yes.
Further, the force F3 applied to the floating bush 32A from the upper arc h3 of the bearing housing 13 can be made smaller than the force F4 applied to the floating bush 32E from the lower arc h4.

Therefore, as in the fourth embodiment, in addition to the squeeze force F1 that floats the turbine rotor shaft 20, a moment M that floats the floating bush 32A is generated. The rotating shaft 14 and the floating bush 32E can easily float. Therefore, the vibration damping effect on the rotating shaft system can be enhanced and the rotating shaft system can be stably supported.
Preferably, when the force F4−the force F3> the resultant force Fr is satisfied, the floating bush 32A can be further lifted.

  According to the present invention, it is possible to realize a simple and low-cost bearing device that facilitates floating of the floating bush and enhances the vibration damping effect on the rotating shaft system in the rotating shaft having the floating bush having a squeeze film damper function. .

DESCRIPTION OF SYMBOLS 10 Exhaust turbine supercharger 11 Turbine housing 11a Outlet passage 11b Inlet passage 12 Compressor housing 12a Air inlet 13 Bearing housing 14 Rotating shaft 15 Turbine blade 16 Turbine nozzle 17 Compressor impeller 18 Diffuser 19 Outlet scroll 20 Turbine rotor shaft 21 Disc 22 Thrust Bearing 23 Spray hole 24 Cooling air supply pipe 26 Lubricating oil passage 30A, 30B, 30C, 30D, 30E Bearing device 32A, 32B, 32C, 32D Floating bush 33 Anti-rotation restricting device 34 Guide groove (concave portion)
36 Non-rotating pin (convex)
38a, 38b Semi-arc 40a, 40b Stepped surface 42a, 42b, 42c Arc 44 Groove B, C, D Intersection G Gravity Fr Resulting force M Moment a Air cs Sealed space e Exhaust gas h1, h3 Upper arc h2, h4 Lower arc o Lubricant ws wedge space

Claims (11)

A bearing housing including a bearing chamber filled with lubricating oil;
A floating bush disposed in the bearing chamber;
A rotating shaft at least partially disposed within the floating bush;
A convex portion provided on one of the floating bush and the bearing housing;
A bearing device comprising: a concave portion provided on the other of the floating bush and the bearing housing and receiving the convex portion so as to reciprocate in a radial direction inclined with respect to a vertical direction. The convex portion is a detent pin provided on the floating bush;
The bearing device according to claim 1, wherein the recess is a guide groove provided in the bearing housing. At least a part of the rotating shaft and the floating bush are subjected to a squeeze force on at least a part of the rotating shaft by lubricating oil existing in a wedge space formed between at least a part of the rotating shaft and the floating bush. Configured to
The bearing device according to claim 2, wherein the guide groove is disposed so as to extend along a direction in which the squeeze force acts.   The bearing device according to any one of claims 1 to 3, wherein an inner surface of the floating bush includes a plurality of arcs in a cross-sectional view.   5. The bearing device according to claim 4, wherein an inner surface of the floating bush includes a plurality of arcs whose curvature center positions are relatively different in a cross-sectional view.   The bearing device according to claim 5, wherein an inner surface of the floating bush includes two semicylinders having relatively different curvature center positions and at least one stepped surface connecting ends of the two semicylinders.   The bearing device according to claim 4, wherein the plurality of arcs have mutually equal lengths. The outer surface of the floating bush and the inner surface of the bearing housing have two regions located between the position of the detent pin and the position opposite to the position of the detent pin in the circumferential direction of the floating bush. ,
The bearing device according to any one of claims 1 to 7, wherein the two regions of at least one of the outer surface of the floating bush and the inner surface of the bearing housing have different shapes at least partially.   The bearing device according to claim 8, wherein an outer surface of the floating bush has an uneven portion in at least a part of a region including a vertex in the vertical direction among the two regions. The inner surface of the bearing housing includes an upper arc that forms one region including the apex in the vertical direction of the two regions in a cross-sectional view, and a lower arc that forms the other region,
The bearing device according to claim 8, wherein a curvature radius of the upper arc is larger than a curvature radius of the lower arc. At least a part of the rotating shaft and the floating bush are subjected to a squeeze force on at least a part of the rotating shaft by lubricating oil existing in a wedge space formed between at least a part of the rotating shaft and the floating bush. Configured to
The shape of at least one of the outer surface of the floating bush and the inner surface of the bearing housing is such that a force that reduces the resultant force of gravity and squeeze force acting on at least a part of the rotating shaft is floating from the inner surface of the bearing housing. The bearing device according to claim 8, wherein the bearing device is formed to act on the bush.

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