Tilting pad for bearing, and bearing

Abstract

To provide a technology capable of suppressing increase in size of a tilting pad.SOLUTION: A tilting pad 32A according to one embodiment of the present disclosure comprises: an inner peripheral surface 32A1 facing a rotational shaft 20, and a groove part 32A3 provided on the inner peripheral surface 32A1, recessed in a wedge shape with the inner peripheral surface 32A1 as reference, and extending in an axial direction parallel to the rotational shaft 20. For example, the groove part 32A3 has a wedge-shaped recess that becomes deeper in a rotation direction of the rotational shaft 20.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to tilting pads for bearings and the like. [Background technology]

[0002] BACKGROUND ART A tilting pad type bearing is known in the art (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 60-140876 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in tilting pad bearings, radial loads can be supported by the reaction force of dynamic pressure generated by the wedge effect of the fluid film formed by the lubricating fluid between the tilting pad and the rotating shaft. Therefore, in order to obtain a higher reaction force against the radial load, it is necessary to ensure a large surface area for the surface facing the rotating shaft, which may lead to an increase in the size of the tilting pad.

[0005] In view of the above problem, an object of the present invention is to provide a technology that can prevent the tilting pad from becoming larger. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, an inner circumferential surface facing the rotation shaft; a groove portion provided on the inner circumferential surface, recessed in a wedge shape with respect to the inner circumferential surface, and extending in an axial direction parallel to the rotation axis, A tilting pad for a bearing is provided.

[0007] In another embodiment of the present disclosure, a tilting pad for the bearing as described above; A bearing is provided. [Effects of the Invention]

[0008] According to the above-described embodiment, it is possible to prevent the tilting pad from becoming large. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a side view showing the structure of an example of an expansion turbine. [Figure 2] 1 is a cross-sectional view showing the structure of an example of an expansion turbine. [Figure 3] FIG. 1 is a diagram showing a first example of a tilting pad. [Figure 4] FIG. 10 is a diagram showing a second example of a tilting pad. [Figure 5] FIG. 1 is a diagram illustrating an example of a hydrogen gas filling system. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] [Expansion turbine structure] The structure of an expansion turbine 1 according to this embodiment will be described with reference to FIGS.

[0012] Fig. 1 is a side view showing the structure of an example of an expansion turbine 1. Fig. 2 is a cross-sectional view showing the structure of an example of an expansion turbine 1.

[0013] 1, the housing 31 is drawn as a vertical cross section in order to clearly show the main components of the expansion turbine 1. Hereinafter, in this specification, the axial direction, radial direction, and circumferential direction based on the rotation axis AX of the expansion turbine 1 may be simply referred to as the "axial direction," the "radial direction," and the "circumferential direction" unless otherwise specified. In addition, in FIG. 2, the rotation shaft 20 rotates clockwise.

[0014] As shown in FIG. 1, the expansion turbine 1 includes a rotating shaft 20, a bearing device 30, an impeller 40, and an energy consuming section 50.

[0015] The rotary shaft 20 is disposed so that its axis coincides with the rotary axis AX of the expansion turbine 1 .

[0016] An impeller 40 for expanding a process gas is attached to one end (the lower end in this example) of the rotating shaft 20. The process gas is, for example, hydrogen gas. Alternatively, the process gas may be helium gas, nitrogen gas, or air.

[0017] An energy consuming unit 50 is attached to the other end (the upper end in this example) of the rotating shaft 20. The energy consuming unit 50 can consume the rotational energy of the rotating shaft 20 driven by the process gas. The energy consuming unit 50 is, for example, an impeller of a compressor 410 (see FIG. 5) described below. The energy consuming unit 50 may also be a brake fan for braking or a generator.

[0018] The bearing device 30 supports the radial load and thrust load on the rotating shaft 20 rotating at high speed.

[0019] The bearing device 30 includes a housing 31, a radial bearing 32, a collar 33, and a thrust bearing 34.

[0020] The housing 31 supports a radial bearing 32 and a thrust bearing 34 .

[0021] In this example, the rotating shaft 20 passes through the housing 31 in the vertical direction. Also, as described above, the rotation axis AX of the expansion turbine 1 may be arranged along the horizontal direction, in which case the rotating shaft 20 passes through the housing 31 in the horizontal direction. The impeller 40 is attached to one end (in this example, the lower end) of the rotating shaft 20 that is exposed from one end (in this example, the lower end) of the housing 31, and the energy consuming unit 50 is attached to the other end (in this example, the upper end) of the rotating shaft 20 that is exposed from the other end (in this example, the upper end) of the housing 31.

[0022] The radial bearing 32 supports a radial load on the rotating shaft 20. For example, as shown in Fig. 1, the radial bearing 32 is a tilting pad type radial bearing.

[0023] In this example, two radial bearings 32 are provided, one at each end in the axial direction inside the housing 31.

[0024] The radial bearing 32 includes a tilting pad 32A, a pivot 32B, an elastic body 32C, and an adjustment portion 32D.

[0025] The tilting pad 32A is disposed so as to face the rotating shaft 20 in the radial space between the rotating shaft 20 and the housing 31. A plurality of tilting pads 32A (three in this example) are disposed in the circumferential direction. For example, the tilting pads 32A are disposed at angular positions set at approximately equal intervals in the circumferential direction. The inner peripheral surface 32A1 of the tilting pad 32A facing the rotating shaft 20 is formed into an arc-shaped curved surface that follows the outer shape of the rotating shaft 20 when viewed along the axial direction, for example. The outer peripheral surface 32A2 of the tilting pad 32A that abuts against the pivot 32B is formed into a curved surface, for example, a spherical surface. The inner peripheral surface 32A1 and the outer peripheral surface 32A2 of the tilting pad 32A are, for example, coated with a special coating to increase hardness.

[0026] 1 and 2 show only the basic shape of the tilting pad 32A, and the detailed structure will be described later with reference to FIG. 3 or FIG.

[0027] The pivot 32B is disposed so as to abut against the radial outside of the tilting pad 32A (specifically, the outer peripheral surface 32A2). One pivot 32B is provided for each tilting pad 32A. That is, the same number of pivots 32B as the number of tilting pads 32A (three in this example) are provided, and the multiple pivots 32B are disposed at circumferential positions (angular positions) where they can abut against the outer peripheral surface 32A2 of the corresponding tilting pad 32A. The contact portion of the pivot 32B with the tilting pad 32A is formed into a curved surface, such as a spherical surface. This allows the tilting pad 32A, which has the curved outer peripheral surface 32A2, to move freely while abutting against the pivot 32B. The contact portion of the pivot 32B with the tilting pad 32A is, for example, coated with a special coating to increase hardness.

[0028] When the rotating shaft 20 is stationary, the outer peripheral surface 32A2 of the tilting pad 32A and the pivot 32B are in surface contact. In contrast, when the rotational speed of the rotating shaft 20 increases to a certain extent, a gas film of lubricating gas (hereinafter referred to as "bearing gas" for convenience) supplied to the inside of the housing 31 through the injection holes 34A is formed between the outer peripheral surface 32A2 of the tilting pad 32A and the pivot 32B. As a result, when the rotational speed of the rotating shaft 20 is relatively high, the outer peripheral surface of the tilting pad 32A and the pivot 32B are in a non-contact state.

[0029] The elastic body 32C abuts against the outer side of the pivot 32B in the radial direction, and generates a biasing force for pressing the tilting pad 32A toward the rotation shaft 20 via the pivot 32B. The elastic body 32C is, for example, a coil spring. For example, as shown in FIG. 2, the elastic body 32C may be provided for only some of the pivots 32B (in this example, three pivots 32B) among the plurality of pivots 32B. Alternatively, the elastic body 32C may be provided for each pivot 32B. That is, the same number of elastic bodies 32C as the number of pivots 32B (in this example, three) may be provided.

[0030] The pivot 32B, or a combination of the pivot 32B and the elastic body 32C, is disposed in a radially extending through-hole provided in the housing 31. The housing 31 is provided with the same number of through-holes as the pivots 32B (three in this example), and the multiple through-holes are formed at circumferential positions (angular positions) corresponding to the angular positions at which the multiple tilting pads 32A are disposed.

[0031] The adjustment unit 32D is disposed so as to abut against the radially outer side of the elastic body 32C. An adjustment unit 32D is provided for each combination of pivot 32B and elastic body 32C. That is, the same number of adjustment units 32D (one in this example) as the number of pivots 32B and elastic bodies 32C are provided. The adjustment unit 32D is attached to the housing 31 so as to be able to adjust the radially outer end position of the elastic body 32C. This makes it possible to adjust the expansion / contraction state of the elastic body 32C and adjust the biasing force with which the elastic body 32C presses the tilting pad 32A against the rotation shaft 20 via the pivot 32B.

[0032] For example, the adjustment portion 32D is a male screw member that can be screwed from the outside in the radial direction into a female screw portion that is formed on the radial inner surface of a through hole that houses the pivot 32B and the elastic body 32C in the housing 31. This makes it possible to adjust the radial outer end position of the elastic body 32C by adjusting the amount of screwing of the male screw member that serves as the adjustment portion 32D.

[0033] The collar 33 is attached to the rotary shaft 20 and has a disk shape centered on the rotary shaft 20. The collar 33 is provided inside the housing 31 at the center in the axial direction.

[0034] The collar 33 is configured to be able to receive a reaction force (hereinafter referred to as a "thrust reaction force") generated by the thrust bearing 34 in response to the thrust load of the rotary shaft 20.

[0035] The thrust bearing 34 supports a thrust load on the rotary shaft 20. Specifically, the thrust bearing 34 generates a thrust reaction force on the collar 33.

[0036] The thrust bearing 34 is disposed so as to face the collar 33 in the axial direction. For example, as shown in Fig. 1, two thrust bearings 34 are provided, and each is disposed so as to be adjacent to both one end (in this example, the lower end) and the other end (in this example, the upper end) of the rotating shaft 20 when viewed from the collar 33.

[0037] For example, as shown in FIG. 1 , the thrust bearing 34 is a hydrostatic gas bearing. Specifically, the thrust bearing 34 has injection holes 34A that inject bearing gas toward the collar 33. For example, the injection holes 34A are provided at predetermined intervals in the circumferential direction. The injection holes 34A are provided in the housing 31 and communicate with a gas supply path 31A that connects to the outside of the expansion turbine 1, and lubricating gas (bearing gas) is supplied to the injection holes 34A from the outside of the expansion turbine 1. The bearing gas is, for example, the same type of gas as the process gas introduced into the expansion turbine 1 (specifically, the impeller 40). In this case, as described below, the process gas before being introduced into the expansion turbine 1 is branched and supplied to the thrust bearing 34. Alternatively, the bearing gas may be a type of gas dedicated to the bearing device 30 that is different from the process gas introduced into the expansion turbine 1.

[0038] The injected bearing gas is discharged to the outside of the expansion turbine 1 through a through-hole 31B provided at a location radially outward from the collar 33 in the housing 31. For example, the bearing gas discharged through the through-hole 31B is released into the atmosphere. Furthermore, if the bearing gas is the same type of gas as the process gas, the bearing gas discharged through the through-hole 31B may be reused by being returned to the path of the process gas before being introduced into the expansion turbine 1.

[0039] The injection holes 34A are provided on the surface of the thrust bearing 34 facing the collar 33, and are formed so that the injection direction of the bearing gas is in the axial direction. This allows the bearing gas injected from the injection holes 34A to generate a thrust reaction force in the collar 33. Furthermore, even if the rotating shaft 20 tilts due to runout or vibration of the rotating shaft 20, causing the collar 33 to approach the thrust bearing 34, the action of the injected bearing gas can suppress abnormal approach due to an increase in the tilt of the rotating shaft 20. As a result, contact between the collar 33 and the thrust bearing 34 can be suppressed.

[0040] 1, the thrust bearing 34 may be a dynamic pressure gas bearing that supports the thrust load of the rotating shaft 20 by gas film pressure between it and the collar 33. In this case, the injection holes 34A are omitted. The thrust bearing 34 may also be a combination of both the dynamic pressure type and the static pressure type.

[0041] [First example of tilting pad structure] Next, a first example of the structure of the tilting pad 32A of the radial bearing 32 according to this embodiment will be described with reference to FIG.

[0042] FIG. 3 is a diagram showing a first example of the structure of the tilting pad 32A.

[0043] 3A and 3B. Fig. 3A is a perspective view of the tilting pad 32A. Fig. 3B is a cross-sectional view of the tilting pad 32A in a state where it is incorporated into the expansion turbine 1, i.e., a cross-sectional view taken along a plane perpendicular to the rotation axis 20.

[0044] As shown in FIG. 3, the tilting pad 32A has a groove 32A3.

[0045] As shown in FIG. 3A, the groove 32A3 is provided on the inner circumferential surface 32A1 of the tilting pad 32A so as to extend in the axial direction, that is, parallel to the rotation axis 20.

[0046] 3A, a plurality of grooves 32A3 (three in this example) are provided. The plurality of grooves 32A3 are arranged side by side in the circumferential direction. Alternatively, the number of grooves 32A3 may be one.

[0047] 3B, the groove 32A3 is recessed in a wedge shape with respect to the inner circumferential surface 32A1. Specifically, the groove 32A3 is formed so that its depth increases in the rotation direction DR of the rotating shaft 20. In other words, the groove 32A3 has a wedge-shaped recess whose depth decreases in the direction opposite to the rotation direction DR of the rotating shaft 20.

[0048] As the rotating shaft 20 rotates, bearing gas flows in and out between the rotating shaft 20 and the inner circumferential surface 32A1 of the tilting pad 32A in the rotational direction. As described above, the tilting pad 32A can change its position relative to the pivot 32B. As shown in FIG. 3B , during steady rotation of the rotating shaft 20, the tilting pad 32A tilts so that the gap between the inner circumferential surface 32A1 and the rotating shaft 20 becomes smaller from the inlet to the outlet of the inflowing bearing gas, i.e., as it progresses in the rotational direction DR of the rotating shaft 20. As a result, a wedge-shaped gas film is formed between the rotating shaft 20 and the inner circumferential surface 32A1 of the tilting pad 32A, generating dynamic pressure due to the wedge effect. Therefore, the radial bearing 32 can support a radial load by the dynamic pressure of the gas film between the inner circumferential surface 32A1 of the tilting pad 32A and the rotating shaft 20.

[0049] In this example, a portion of the bearing gas flowing between the inner circumferential surface 32A1 of the tilting pad 32A and the rotating shaft 20 is drawn into the groove 32A3. As a result, the bearing gas flowing into the groove 32A3 expands as it flows along the rotational direction DR of the rotating shaft 20, gradually increasing the gap between the rotating shaft 20 and the groove 32A3. Conversely, at the end of the groove 32A3, the bearing gas pressure inside the groove 32A3 changes relatively rapidly, decreasing the gap between the rotating shaft 20 and the groove 32A3, generating high pressure, i.e., a repulsive force that pushes back the rotating shaft 20. As a result, the groove 32A3 forms a wedge-shaped gas film corresponding to the depth of its recess. Therefore, the radial bearing 32 can support a radial load not only by the dynamic pressure of the gas film between the inner circumferential surface 32A1 of the tilting pad 32A and the rotating shaft 20 but also by the dynamic pressure of the gas film inside the groove 32A3. Therefore, the radial bearing 32 can increase the radial reaction force for supporting the radial load without increasing the area of ​​the inner surface 32A1 of the tilting pad 32A or while suppressing an increase in the area of ​​the inner surface 32A1.

[0050] In addition, in this example, the radial bearing 32 can further increase the radial reaction force for supporting the radial load by the action of the plurality of grooves 32A3.

[0051] [Second example of tilting pad structure] Next, a second example of the structure of the tilting pad 32A of the radial bearing 32 according to this embodiment will be described with reference to FIG.

[0052] Hereinafter, in this example, the same symbols are used for configurations that are the same as or correspond to those in the first example (FIG. 3) described above, and the explanation will focus on the parts that are different from the first example described above, and explanations of the same or corresponding content as the first example described above may be omitted.

[0053] FIG. 4 is a diagram showing a second example of the structure of the tilting pad 32A.

[0054] Specifically, FIG. 4 is a cross-sectional view of the tilting pad 32A in a state where it is assembled into the expansion turbine 1, that is, a cross-sectional view taken along a plane perpendicular to the rotation axis 20.

[0055] As shown in FIG. 4, the tilting pad 32A has a groove 32A3, similar to the first example described above.

[0056] In this example, the end of the groove 32A3 in the rotational direction is formed to have an inclined surface 32A4 at an obtuse angle relative to the inner circumferential surface 32A1. This makes it easier for the bearing gas flowing between the inner circumferential surface 32A1 of the tilting pad 32A and the rotating shaft 20 to be entrained in the groove 32A3. As a result, the groove 32A3 can more effectively form a wedge-shaped gas film within itself. This allows the radial bearing 32 to more effectively increase the radial reaction force for supporting the radial load.

[0057] [Example of expansion turbine application] Next, an application example of the expansion turbine 1 according to this embodiment will be described with reference to FIG.

[0058] FIG. 5 is a diagram showing an example of a hydrogen gas filling system SYS.

[0059] The hydrogen gas filling system SYS is installed, for example, in a hydrogen station for filling a vehicle VCL with hydrogen gas.

[0060] As shown in FIG. 5, the hydrogen gas filling system SYS includes a hydrogen gas compression facility 100, an expansion valve 200, a hydrogen gas line 300, a pre-cooling system 400, and a dispenser 500.

[0061] The hydrogen gas compression equipment 100 compresses hydrogen gas supplied from a tank as a process gas, boosts the pressure to a predetermined level, and outputs the compressed hydrogen gas.

[0062] The expansion valve 200 adiabatically expands (isenthalpic expands) the hydrogen gas output from the hydrogen gas compression equipment 100. At this time, since the temperature of the hydrogen gas before expansion is higher than the inversion temperature (-58°C), the temperature of the hydrogen gas after expansion rises due to the Joule-Thomson effect.

[0063] The hydrogen gas line 300 supplies the expanded hydrogen gas output from the expansion valve 200 to the pre-cooling system 400 .

[0064] The pre-cooling system 400 cools the hydrogen gas supplied from the hydrogen gas line 300 and supplies it to the dispenser 500 .

[0065] The pre-cooling system 400 includes a compressor 410 , a chiller 420 , a cold source 430 , and an expansion section 440 .

[0066] The compressor 410 compresses the hydrogen gas supplied from the hydrogen gas line 300 .

[0067] The cooler 420 exchanges heat between a refrigerant supplied from a cold heat source 430 and the hydrogen gas compressed by the compressor 410, thereby cooling the hydrogen gas.

[0068] The cold heat source 430 supplies a refrigerant having a temperature lower than that of the hydrogen gas output from the compressor 410 to the cooler 420 and circulates it.

[0069] A cooler similar to the cooler 420 may be provided upstream of the compressor 410, and the hydrogen gas in the hydrogen gas line 300 may be introduced into the compressor 410 after being cooled by the cooler.

[0070] The expansion section 440 expands the hydrogen gas cooled by the cooler 420. This allows the hydrogen gas to expand and lower its temperature. Furthermore, by expanding the hydrogen gas compressed by the compressor 410, the expansion ratio becomes relatively large, and as a result, the temperature of the hydrogen gas can be lowered more significantly. Therefore, the temperature of the hydrogen gas can be lowered to an appropriate level without requiring a pre-cooling system that requires a refrigerator equipment including, for example, a compressor, a condenser, an expansion valve, an evaporator, an accumulator, and the like.

[0071] In this example, the compressor 410 and the expansion section 440 are realized by the expansion turbine 1. Specifically, the expansion turbine 1 realizes the function of the expansion section 440 by expanding hydrogen gas with the impeller 40 at one end of the rotary shaft 20, and realizes the function of the compressor 410 by compressing the hydrogen gas with the impeller serving as the energy consumption section 50 at the other end of the rotary shaft 20.

[0072] The dispenser 500 fills the hydrogen tank TNK of the vehicle VCL with high-pressure hydrogen gas supplied from the pre-cooling system 400. The vehicle VCL is, for example, a fuel cell vehicle equipped with a fuel cell capable of generating electricity using hydrogen gas as fuel.

[0073] In this way, the expansion turbine 1 can be applied to the pre-cooling system 400 of the hydrogen gas filling system SYS.

[0074] [Other embodiments] Next, another embodiment will be described.

[0075] The above-described embodiment may be modified or changed as appropriate.

[0076] For example, the bearing device 30 of the above-described embodiment, in particular the radial bearing 32, may be applied to other rotary machines other than the expansion turbine 1. The other rotary machines include, for example, jet engines, gas turbines, superchargers, compressors, pumps, water turbines, etc.

[0077] In the above-described embodiment and its variations and modifications, the radial bearing 32 may use a liquid such as oil as a lubricant instead of a gas (bearing gas).

[0078] [Effect] Next, the operation of the tilting pad for a bearing and the bearing device according to this embodiment will be described.

[0079] For example, in a tilting pad bearing, increasing the area of ​​the inner peripheral surface of the tilting pad corresponding to the rotating shaft is considered in order to obtain a relatively large reaction force against a load (i.e., a radial load). This may result in an increase in the size of the tilting pad. Furthermore, this requires increasing the width of the tilting pad in the axial direction based on the axis of the rotating shaft, which makes the tilting pad more likely to swing three-dimensionally around the pivot 32B as a fulcrum. As a result, the tilting pad is more likely to be damaged by contact between the tilting pad and the rotating shaft. Furthermore, in small rotating machines, there are spatial limitations on the placement of the tilting pad, and it may not be possible to increase the area of ​​the inner peripheral surface of the tilting pad.

[0080] In contrast, in a first aspect of this embodiment, a tilting pad for a bearing includes an inner circumferential surface facing a rotation shaft, and a groove portion provided on the inner circumferential surface, recessed in a wedge shape with respect to the inner circumferential surface, and extending in an axial direction parallel to the rotation shaft. The tilting pad for a bearing is, for example, the tilting pad 32A described above. The rotation shaft is, for example, the rotation shaft 20 described above. The inner circumferential surface is, for example, the inner circumferential surface 32A1 described above. The groove portion is, for example, the groove portion 32A3 described above.

[0081] This allows the tilting pad for bearings to utilize the dynamic pressure due to the fluid film inside the wedge-shaped groove in addition to the dynamic pressure due to the fluid film between the inner circumferential surface and the rotating shaft. Therefore, the tilting pad for bearings can increase the radial reaction force for supporting the load (i.e., the radial load) without increasing the area of ​​the inner circumferential surface, and as a result, it is possible to prevent the tilting pad from becoming larger.

[0082] In a second aspect of this embodiment, based on the first aspect described above, the groove may have a wedge-shaped recess whose depth increases in the direction of rotation of the rotating shaft, for example, the direction of rotation DR described above.

[0083] As a result, the tilting pad for bearings uses a gap that deepens in the rotational direction to expand the lubricating fluid flowing inside the groove in the rotational direction of the rotating shaft, and then suddenly reduces the gap at the end of the groove in the rotational direction of the rotating shaft, thereby utilizing a wedge effect.As a result, the tilting pad for bearings can increase the radial reaction force for supporting the load without increasing the area of ​​the inner circumferential surface.

[0084] In a third aspect of this embodiment, based on the second aspect described above, the groove may be formed so that the end portion in the rotational direction has an inclined surface that forms an obtuse angle with respect to the inner circumferential surface. The inclined surface is, for example, the inclined surface 32A4 described above.

[0085] This allows the tilting pad for a bearing to more effectively draw in the lubricating fluid that flows between its inner circumferential surface and the rotating shaft and that flows in the direction of rotation of the rotating shaft into the groove.As a result, the tilting pad for a bearing can more effectively generate dynamic pressure due to the wedge effect of the lubricating fluid that flows in the direction of rotation of the rotating shaft inside the groove.As a result, the tilting pad for a bearing can more effectively increase the radial reaction force for supporting the load.

[0086] In addition, in a fourth aspect of this embodiment, based on any one of the first to third aspects described above, the groove portions may be provided in multiple numbers and aligned along the circumferential direction of the rotating shaft.

[0087] This allows the tilting pad for the bearing to further increase the radial reaction force for supporting the load.

[0088] In a fifth aspect of this embodiment, a bearing includes a tilting pad for the bearing of any one of the first to fourth aspects described above. The bearing is, for example, the radial bearing 32 described above.

[0089] This allows the bearing to prevent the tilting pad from becoming too large.

[0090] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0091] 1. Expansion turbine 20 Rotation axis 30 Bearing device 32 Radial bearing 32A Tilting Pad 32A1 Inner surface 32A2 Outer surface 32A3 Groove 32A4 Slope 32B Pivot 32C Elastic body 32D adjustment section

Claims

1. an inner circumferential surface facing the rotation shaft; a groove portion provided on the inner circumferential surface, recessed in a wedge shape with respect to the inner circumferential surface, and extending in an axial direction parallel to the rotation axis, Tilting pad for bearings.

2. The groove portion has a wedge-shaped recess whose depth increases as it advances in the rotation direction of the rotation shaft.

2. A tilting pad for a bearing according to claim 1.

3. The groove portion is formed so that an end portion in the rotation direction has an inclined surface at an obtuse angle with respect to the inner circumferential surface.

3. A tilting pad for a bearing according to claim 2.

4. The groove portion is provided in plurality so as to be aligned along the circumferential direction of the rotation shaft. A tilting pad for a bearing according to any one of claims 1 to 3.

5. A bearing comprising a tilting pad for a bearing according to any one of claims 1 to 3. Bearing.

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